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Deantas-Jahn C, Mendoza SN, Licona-Cassani C, Orellana C, Saa PA. Metabolic modeling of Halomonas campaniensis improves polyhydroxybutyrate production under nitrogen limitation. Appl Microbiol Biotechnol 2024; 108:310. [PMID: 38662130 PMCID: PMC11045607 DOI: 10.1007/s00253-024-13111-8] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/21/2023] [Revised: 02/25/2024] [Accepted: 03/18/2024] [Indexed: 04/26/2024]
Abstract
Poly-hydroxybutyrate (PHB) is an environmentally friendly alternative for conventional fossil fuel-based plastics that is produced by various microorganisms. Large-scale PHB production is challenging due to the comparatively higher biomanufacturing costs. A PHB overproducer is the haloalkaliphilic bacterium Halomonas campaniensis, which has low nutritional requirements and can grow in cultures with high salt concentrations, rendering it resistant to contamination. Despite its virtues, the metabolic capabilities of H. campaniensis as well as the limitations hindering higher PHB production remain poorly studied. To address this limitation, we present HaloGEM, the first high-quality genome-scale metabolic network reconstruction, which encompasses 888 genes, 1528 reactions (1257 gene-associated), and 1274 metabolites. HaloGEM not only displays excellent agreement with previous growth data and experiments from this study, but it also revealed nitrogen as a limiting nutrient when growing aerobically under high salt concentrations using glucose as carbon source. Among different nitrogen source mixtures for optimal growth, HaloGEM predicted glutamate and arginine as a promising mixture producing increases of 54.2% and 153.4% in the biomass yield and PHB titer, respectively. Furthermore, the model was used to predict genetic interventions for increasing PHB yield, which were consistent with the rationale of previously reported strategies. Overall, the presented reconstruction advances our understanding of the metabolic capabilities of H. campaniensis for rationally engineering this next-generation industrial biotechnology platform. KEY POINTS: A comprehensive genome-scale metabolic reconstruction of H. campaniensis was developed. Experiments and simulations predict N limitation in minimal media under aerobiosis. In silico media design increased experimental biomass yield and PHB titer.
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Affiliation(s)
- Carolina Deantas-Jahn
- Departamento de Ingeniería Química y Bioprocesos, Escuela de Ingeniería, Pontificia Universidad Católica de Chile, Santiago, Chile
| | - Sebastián N Mendoza
- Departamento de Ingeniería Química y Bioprocesos, Escuela de Ingeniería, Pontificia Universidad Católica de Chile, Santiago, Chile
- Systems Biology Lab, Vrije Universiteit Amsterdam, Amsterdam, Netherlands
| | - Cuauhtemoc Licona-Cassani
- Núcleo de Innovación de Sistemas Biológicos (NISB), FEMSA Biotechnology Center, Tecnológico de Monterrey, Monterrey, Mexico
- Escuela de Ingeniería y Ciencias, Tecnológico de Monterrey, Monterrey, Mexico
| | - Camila Orellana
- Departamento de Ingeniería Química y Bioprocesos, Escuela de Ingeniería, Pontificia Universidad Católica de Chile, Santiago, Chile
| | - Pedro A Saa
- Departamento de Ingeniería Química y Bioprocesos, Escuela de Ingeniería, Pontificia Universidad Católica de Chile, Santiago, Chile.
- Instituto de Ingeniería Matemática y Computacional, Pontificia Universidad Católica de Chile, Santiago, Chile.
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Xu X, Song F, Zhang G, Ma L, Yang N. Proteomic insights into the response of Halomonas sp. MNB13 to excess Mn(Ⅱ) and the role of H 2S in Mn(Ⅱ) resistance. Environ Res 2024; 246:118157. [PMID: 38199468 DOI: 10.1016/j.envres.2024.118157] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 10/15/2023] [Revised: 12/23/2023] [Accepted: 01/06/2024] [Indexed: 01/12/2024]
Abstract
Halomonas spp. are moderately halophilic bacteria with the ability to tolerate various heavy metals. However, the role of basic cellular metabolism, particularly amino acid metabolism, has not been investigated in Halomonas spp. under excess Mn(Ⅱ). The strain Halomonas sp. MNB13 was isolated from a deep-sea ferromanganese nodule and can tolerate 80 mM Mn(Ⅱ). To comprehensively explore the mechanisms underlying its resistance to excess Mn(Ⅱ), we conducted a comparative proteome analysis. The data revealed that both 10 mM and 50 mM Mn(Ⅱ) significantly up-regulated the expression of proteins involved in Mn(Ⅱ) transport (MntE), oxidative stress response (alkyl hydroperoxide reductase and the Suf system), and amino acid metabolism (arginine, cysteine, methionine, and phenylalanine). We further investigated the role of cysteine metabolism in Mn(Ⅱ) resistance by examining the function of its downstream product, H2S. Consistent with the up-regulation of cysteine desulfurase, we detected an elevated level of H2S in Halomonas sp. MNB13 cells under Mn(Ⅱ) stress, along with increased intracellular levels of H2O2 and O2•-. Upon exogenous addition of H2S, we observed a significant restoration of the growth of Halomonas sp. MNB13. Moreover, we identified decreased intracellular levels of H2O2 and O2•- in MNB13 cells, which coincided with a decreased formation of Mn-oxides during cultivation. In contrast, in cultures containing NaHS, the residual Mn(Ⅱ) levels were higher than in cultures without NaHS. Therefore, H2S improves Mn(Ⅱ) tolerance by eliminating intracellular reactive oxygen species rather than decreasing Mn(Ⅱ) concentration in solution. Our findings indicate that cysteine metabolism, particularly the intermediate H2S, plays a pivotal role in Mn(Ⅱ) resistance by mitigating the damage caused by reactive oxygen species. These findings provide new insights into the amino acid mechanisms associated with Mn(Ⅱ) resistance in bacteria.
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Affiliation(s)
- Xiuli Xu
- School of Ocean Sciences, China University of Geosciences, 29 Xueyuan Road, Beijing, 100083, China
| | - Fuhang Song
- School of Light Industry, Beijing Technology and Business University, 11 Fucheng Road, Beijing, 100048, China
| | - Guoliang Zhang
- Center of Deep Sea Research, Institute of Oceanology, Chinese Academy of Sciences, 7 Nanhai Road, Qingdao, 266071, China
| | - Linlin Ma
- Griffith Institute for Drug Discovery, School of Environment and Science, Griffith University, Brisbane, 4111, Australia
| | - Na Yang
- CAS Key Laboratory of Experimental Marine Biology, Center for Ocean Mega-Science, Institute of Oceanology, Chinese Academy of Sciences, 7 Nanhai Road, Qingdao, 266071, China; Laboratory for Marine Biology and Biotechnology, Qingdao National Laboratory for Marine Science and Technology, 1 Wenhai Road, Qingdao, 266237, China.
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Yu J, Zhang Y, Liu H, Liu Y, Mohsin A, Liu Z, Zheng Y, Xing J, Han J, Zhuang Y, Guo M, Wang Z. Temporal dynamics of stress response in Halomonas elongata to NaCl shock: physiological, metabolomic, and transcriptomic insights. Microb Cell Fact 2024; 23:88. [PMID: 38519954 PMCID: PMC10960403 DOI: 10.1186/s12934-024-02358-5] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/14/2024] [Accepted: 03/06/2024] [Indexed: 03/25/2024] Open
Abstract
BACKGROUND The halophilic bacterium Halomonas elongata is an industrially important strain for ectoine production, with high value and intense research focus. While existing studies primarily delve into the adaptive mechanisms of this bacterium under fixed salt concentrations, there is a notable dearth of attention regarding its response to fluctuating saline environments. Consequently, the stress response of H. elongata to salt shock remains inadequately understood. RESULTS This study investigated the stress response mechanism of H. elongata when exposed to NaCl shock at short- and long-time scales. Results showed that NaCl shock induced two major stresses, namely osmotic stress and oxidative stress. In response to the former, within the cell's tolerable range (1-8% NaCl shock), H. elongata urgently balanced the surging osmotic pressure by uptaking sodium and potassium ions and augmenting intracellular amino acid pools, particularly glutamate and glutamine. However, ectoine content started to increase until 20 min post-shock, rapidly becoming the dominant osmoprotectant, and reaching the maximum productivity (1450 ± 99 mg/L/h). Transcriptomic data also confirmed the delayed response in ectoine biosynthesis, and we speculate that this might be attributed to an intracellular energy crisis caused by NaCl shock. In response to oxidative stress, transcription factor cysB was significantly upregulated, positively regulating the sulfur metabolism and cysteine biosynthesis. Furthermore, the upregulation of the crucial peroxidase gene (HELO_RS18165) and the simultaneous enhancement of peroxidase (POD) and catalase (CAT) activities collectively constitute the antioxidant defense in H. elongata following shock. When exceeding the tolerance threshold of H. elongata (1-13% NaCl shock), the sustained compromised energy status, resulting from the pronounced inhibition of the respiratory chain and ATP synthase, may be a crucial factor leading to the stagnation of both cell growth and ectoine biosynthesis. CONCLUSIONS This study conducted a comprehensive analysis of H. elongata's stress response to NaCl shock at multiple scales. It extends the understanding of stress response of halophilic bacteria to NaCl shock and provides promising theoretical insights to guide future improvements in optimizing industrial ectoine production.
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Affiliation(s)
- Junxiong Yu
- State Key Laboratory of Bioreactor Engineering, East China University of Science and Technology, 130 Meilong Rd, Shanghai, 200237, China
| | - Yue Zhang
- State Key Laboratory of Bioreactor Engineering, East China University of Science and Technology, 130 Meilong Rd, Shanghai, 200237, China
| | - Hao Liu
- State Key Laboratory of Bioreactor Engineering, East China University of Science and Technology, 130 Meilong Rd, Shanghai, 200237, China
| | - Yuxuan Liu
- Department of Chemical Engineering for Energy Resources, East China University of Science and Technology, 130 Meilong Rd, Shanghai, 200237, China
| | - Ali Mohsin
- State Key Laboratory of Bioreactor Engineering, East China University of Science and Technology, 130 Meilong Rd, Shanghai, 200237, China
| | - Zebo Liu
- State Key Laboratory of Bioreactor Engineering, East China University of Science and Technology, 130 Meilong Rd, Shanghai, 200237, China
| | - Yanning Zheng
- State Key Laboratory of Microbial Resources, Institute of Microbiology, Chinese Academy of Sciences, No. 1 Beichen West Road, Chaoyang District, Beijing, 100101, China
| | - Jianmin Xing
- Institute of Process Engineering, Chinese Academy of Sciences, Beijing, 100190, PR China
| | - Jing Han
- State Key Laboratory of Microbial Resources, Institute of Microbiology, Chinese Academy of Sciences, No. 1 Beichen West Road, Chaoyang District, Beijing, 100101, China
| | - Yingping Zhuang
- State Key Laboratory of Bioreactor Engineering, East China University of Science and Technology, 130 Meilong Rd, Shanghai, 200237, China
| | - Meijin Guo
- State Key Laboratory of Bioreactor Engineering, East China University of Science and Technology, 130 Meilong Rd, Shanghai, 200237, China.
| | - Zejian Wang
- State Key Laboratory of Bioreactor Engineering, East China University of Science and Technology, 130 Meilong Rd, Shanghai, 200237, China.
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Liu Y, Song X, Yang W, Wang M, Lian G, Li ZJ. Production of polyhydroxyalkanoates by engineered Halomonas bluephagenesis using starch as a carbon source. Int J Biol Macromol 2024; 261:129838. [PMID: 38307428 DOI: 10.1016/j.ijbiomac.2024.129838] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/25/2023] [Revised: 01/17/2024] [Accepted: 01/27/2024] [Indexed: 02/04/2024]
Abstract
A novel α-amylase Amy03713 was screened and cloned from the starch utilization strain Vibrio alginolyticus LHF01. When heterologously expressed in Escherichia coli, Amy03713 exhibited the highest enzyme activity at 45 °C and pH 7, maintained >50 % of the enzyme activity in the range of 25-75 °C and pH 5-9, and sustained >80 % of the enzyme activity in 25 % (w/v) of NaCl solution, thus showing a wide range of adapted temperatures, pH, and salt concentrations. Halomonas bluephagenesis harboring amy03713 gene was able to directly utilize starch. With optimized amylase expression, H. bluephagenesis could produce poly(3-hydroxybutyrate) (PHB), poly(3-hydroxybutyrate-co-3-hydroxyvalerate) (PHBV), and poly(3-hydroxybutyrate-co-4-hydroxybutyrate) (P34HB). When cultured for PHB production, recombinant H. bluephagenesis was able to grow up to a cell dry weight of 11.26 g/L, achieving a PHB titer of 6.32 g/L, which is the highest titer that has been reported for PHB production from starch in shake flasks. This study suggests that Amy03713 is an ideal amylase for PHA production using starch as the carbon source in H. bluephagenesis.
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Affiliation(s)
- Yuzhong Liu
- Beijing Key Laboratory of Bioprocess, College of Life Science and Technology, Beijing University of Chemical Technology, Beijing 100029, People's Republic of China
| | - Xueqi Song
- Beijing Key Laboratory of Bioprocess, College of Life Science and Technology, Beijing University of Chemical Technology, Beijing 100029, People's Republic of China
| | - Weinan Yang
- Center for Synthetic and Systems Biology, School of Life Sciences, Tsinghua University, Beijing 100084, China
| | - Mengru Wang
- Beijing Key Laboratory of Bioprocess, College of Life Science and Technology, Beijing University of Chemical Technology, Beijing 100029, People's Republic of China
| | - Guoli Lian
- Beijing Key Laboratory of Bioprocess, College of Life Science and Technology, Beijing University of Chemical Technology, Beijing 100029, People's Republic of China
| | - Zheng-Jun Li
- Beijing Key Laboratory of Bioprocess, College of Life Science and Technology, Beijing University of Chemical Technology, Beijing 100029, People's Republic of China.
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Yoo Y, Young Kwon D, Jeon M, Lee J, Kwon H, Lee D, Seong Khim J, Choi YE, Kim JJ. Enhancing poly(3-hydroxybutyrate) production in halophilic bacteria through improved salt tolerance. Bioresour Technol 2024; 394:130175. [PMID: 38086463 DOI: 10.1016/j.biortech.2023.130175] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 11/06/2023] [Revised: 12/06/2023] [Accepted: 12/06/2023] [Indexed: 12/17/2023]
Abstract
Polyhydroxyalkanoates (PHA) have emerged as a promising bio-compound in the industrial application due to their potential to replace conventional petroleum-based plastics with sustainable bioplastics. This study focuses on Halomonas sp. YJPS3-3, a halophilic bacterium, and presents a novel approach to enhance PHA production by exploiting its salt tolerance toward PHA biosynthesis. Through gamma irradiation-induced mutants with enhanced salt tolerance from 15% NaCl to 20% NaCl, mutant halo6 showing a significant 11% increase in PHA yield, was achieved. Moreover, the mutants displayed not only higher PHA content but also remarkable cell morphology with elongation. In addition, this research unravels the genetic determinants behind the elevated PHA content and identifies a corresponding shift in fatty acid composition favoring PHA accumulation. This novel mutant obtained from gamma irradiation with enhanced salt tolerance in halophilic bacteria opens up new avenues not only for the bioplastic industry but also for applications in the production of high-value metabolites.
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Affiliation(s)
- Yeonjae Yoo
- Division of Environmental Science & Ecological Engineering, College of Life Sciences & Biotechnology, Korea University, Seoul 02841, Republic of Korea
| | - Dae Young Kwon
- Division of Environmental Science & Ecological Engineering, College of Life Sciences & Biotechnology, Korea University, Seoul 02841, Republic of Korea
| | - Minseo Jeon
- Advanced Radiation Technology Institute, Korea Atomic Energy Research Institute, Jeongeup 56212, Republic of Korea
| | - Jaehoon Lee
- Department of Plant Biotechnology, College of Life Sciences and Biotechnology, Korea University, Seoul 02841, Republic of Korea
| | - Haeun Kwon
- Department of Plant Biotechnology, College of Life Sciences and Biotechnology, Korea University, Seoul 02841, Republic of Korea
| | - Dongho Lee
- Department of Plant Biotechnology, College of Life Sciences and Biotechnology, Korea University, Seoul 02841, Republic of Korea
| | - Jong Seong Khim
- School of Earth and Environmental Sciences & Research Institute of Oceanography, Seoul National University, Seoul 08826, Republic of Korea
| | - Yoon-E Choi
- Division of Environmental Science & Ecological Engineering, College of Life Sciences & Biotechnology, Korea University, Seoul 02841, Republic of Korea
| | - Jae-Jin Kim
- Division of Environmental Science & Ecological Engineering, College of Life Sciences & Biotechnology, Korea University, Seoul 02841, Republic of Korea.
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6
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Ren K, Zhao Y, Chen GQ, Ao X, Wu Q. Construction of a Stable Expression System Based on the Endogenous hbpB/ hbpC Toxin-Antitoxin System of Halomonas bluephagenesis. ACS Synth Biol 2024; 13:61-67. [PMID: 38100561 DOI: 10.1021/acssynbio.3c00622] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/17/2023]
Abstract
Halomonas bluephagenesis is a halophilic bacterium capable of efficiently producing polyhydroxyalkanoates and other valuable chemicals through high salinity open fermentation, offering an appealing platform for next-generation industrial biotechnology. Various techniques have been developed to engineer Halomonas bluephagenesis, each with its inherent shortcomings. Genome editing methods often entail complex and time-consuming processes, while flexible expression systems relying on plasmids necessitate the use of antibiotics. In this study, we developed a stable recombinant plasmid vector, pHbPBC, based on a novel hbpB/hbpC toxin-antitoxin system found within the endogenous plasmid of Halomonas bluephagenesis. Remarkably, pHbPBC exhibited exceptional stability during 7 days of continuous subculture, eliminating the need for antibiotics or other selection pressures. This stability even rivaled genomic integration, all while achieving higher levels of heterologous expression. Our research introduces a novel approach for genetically modifying and harnessing nonmodel halophilic bacteria, contributing to the advancement of next-generation industrial biotechnology.
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Affiliation(s)
- Kang Ren
- MOE Key Laboratory of Bioinformatics, Center for Synthetic and Systems Biology, School of Life Sciences, Tsinghua University, Beijing 100084, China
| | - Yiqing Zhao
- Beijing No.12 High School, Beijing 100071, China
| | - Guo-Qiang Chen
- Center for Synthetic and Systems Biology, Tsinghua-Peking Center for Life Sciences, School of Life Sciences, Tsinghua University, Beijing 100084, China
| | - Xiang Ao
- MOE Key Laboratory of Bioinformatics, Center for Synthetic and Systems Biology, School of Life Sciences, Tsinghua University, Beijing 100084, China
| | - Qiong Wu
- MOE Key Laboratory of Bioinformatics, Center for Synthetic and Systems Biology, School of Life Sciences, Tsinghua University, Beijing 100084, China
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Yang F, Wang H, Zhao C, Zhang L, Liu X, Park H, Yuan Y, Ye JW, Wu Q, Chen GQ. Metabolic engineering of Halomonas bluephagenesis for production of five carbon molecular chemicals derived from L-lysine. Metab Eng 2024; 81:227-237. [PMID: 38072357 DOI: 10.1016/j.ymben.2023.12.001] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/20/2023] [Revised: 10/28/2023] [Accepted: 12/01/2023] [Indexed: 12/31/2023]
Abstract
5-Aminovaleric acid (5-AVA), 5-hydroxyvalerate (5HV), copolymer P(3HB-co-5HV) of 3-hydroxybutyrate (3HB) and 5HV were produced from L-lysine as a substrate by recombinant Halomonas bluephagenesis constructed based on codon optimization, deletions of competitive pathway and L-lysine export protein, and three copies of davBA genes encoding L-lysine monooxygenase (DavB) and 5-aminovaleramide amidohydrolase (DavA) inserted into its genome to form H. bluephagenesis YF117ΔgabT1+2, which produced 16.4 g L-1 and 67.4 g L-1 5-AVA in flask cultures and in 7 L bioreactor, respectively. It was able to de novo synthesize 5-AVA from glucose by L-lysine-overproducing H. bluephagenesis TD226. Corn steep liquor was used instead of yeast extract for cost reduction during the 5-AVA production. Using promoter engineering based on Pporin mutant library for downstream genes, H. bluephagenesis YF117 harboring pSEVA341-Pporin42-yqhDEC produced 6 g L-1 5HV in shake flask growth, while H. bluephagenesis YF117 harboring pSEVA341-Pporin42-yqhDEC-Pporin278-phaCRE-abfT synthesized 42 wt% P(3HB-co-4.8 mol% 5HV) under the same condition. Thus, H. bluephagenesis was successfully engineered to produce 5-AVA and 5HV in supernatant and intracellular P(3HB-co-5HV) utilizing L-lysine as the substrate.
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Affiliation(s)
- Fang Yang
- School of Life Sciences, Tsinghua University, Beijing, 100084, China
| | - Huan Wang
- School of Life Sciences, Tsinghua University, Beijing, 100084, China
| | - Cuihuan Zhao
- School of Life Sciences, Tsinghua University, Beijing, 100084, China
| | - Lizhan Zhang
- School of Life Sciences, Tsinghua University, Beijing, 100084, China
| | - Xu Liu
- PhaBuilder Biotech Co. Ltd., Shunyi District, Zhaoquan Ying, Beijing, 101309, China
| | - Helen Park
- School of Life Sciences, Tsinghua University, Beijing, 100084, China
| | - Yiping Yuan
- School of Life Sciences, Tsinghua University, Beijing, 100084, China
| | - Jian-Wen Ye
- School of Life Sciences, Tsinghua University, Beijing, 100084, China
| | - Qiong Wu
- School of Life Sciences, Tsinghua University, Beijing, 100084, China
| | - Guo-Qiang Chen
- School of Life Sciences, Tsinghua University, Beijing, 100084, China; Center for Synthetic and Systems Biology, Tsinghua University, Beijing, 100084, China; Tsinghua-Peking Center for Life Sciences, Beijing, China; MOE Key Lab of Industrial Biocatalysis, Dept Chemical Engineering, Tsinghua University, Beijing, 100084, China.
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8
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Park JK, Jeon JM, Yang YH, Kim SH, Yoon JJ. Efficient polyhydroxybutyrate production using acetate by engineered Halomonas sp. JJY01 harboring acetyl-CoA acetyltransferase. Int J Biol Macromol 2024; 254:127475. [PMID: 37863147 DOI: 10.1016/j.ijbiomac.2023.127475] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/11/2023] [Revised: 10/05/2023] [Accepted: 10/15/2023] [Indexed: 10/22/2023]
Abstract
Polyhydroxybutyrate (PHB) is a well-known biodegradable bioplastic synthesized by microorganisms and can be produced from volatile fatty acids (VFAs). Among VFAs acetate can be utilized by Halomonas sp. YLGW01 for growth and PHB production. In this study, Halomonas sp. JJY01 was developed through introducing acetyl-CoA acetyltransferase (atoAD) with LacIq-Ptrc promoter into Halomonas sp. YLGW01. The effect of expression of atoAD on acetate was investigated by comparison with acetate consumption and PHB production. Shake-flask study showed that Halomonas sp. JJY01 increased acetate consumption rate, PHB yield and PHB production (0.27 g/L/h, 0.075 g/g, 0.72 g/L) compared to the wild type strain (0.17 g/L/h, 0.016 g/g, 0.11 g/L). In 10 L fermenter scale fed-batch fermentation, the growth of Halomonas sp. JJY01 resulted in higher acetate consumption rate, PHB yield and PHB titer (0.55 g/L/h, 0.091 g/g, 4.6 g/L) than wild type strain (0.35 g/L/h, 0.067 h/h, 2.9 g/L). These findings demonstrate enhanced acetate utilization and PHB production through the introduction of atoAD in Halomonas strains.
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Affiliation(s)
- Jea-Kyung Park
- Green & Sustainable Materials R&D Department, Korea Institute of Industrial Technology (KITECH), Cheonan-si 31056, Republic of Korea; School of Civil and Environmental Engineering, Yonsei University, Seoul 03722, Republic of Korea
| | - Jong-Min Jeon
- Green & Sustainable Materials R&D Department, Korea Institute of Industrial Technology (KITECH), Cheonan-si 31056, Republic of Korea
| | - Yung-Hun Yang
- Department of Biological Engineering, Konkuk University, Seoul 05029, Republic of Korea
| | - Sang-Hyoun Kim
- School of Civil and Environmental Engineering, Yonsei University, Seoul 03722, Republic of Korea
| | - Jeong-Jun Yoon
- Green & Sustainable Materials R&D Department, Korea Institute of Industrial Technology (KITECH), Cheonan-si 31056, Republic of Korea.
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9
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Ma Y, Ye JW, Lin Y, Yi X, Wang X, Wang H, Huang R, Wu F, Wu Q, Liu X, Chen GQ. Flux optimization using multiple promoters in Halomonas bluephagenesis as a model chassis of the next generation industrial biotechnology. Metab Eng 2024; 81:249-261. [PMID: 38159902 DOI: 10.1016/j.ymben.2023.12.011] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/15/2023] [Revised: 12/16/2023] [Accepted: 12/24/2023] [Indexed: 01/03/2024]
Abstract
Predictability and robustness are challenges for bioproduction because of the unstable intracellular synthetic activities. With the deeper understanding of the gene expression process, fine-tuning has become a meaningful tool for biosynthesis optimization. This study characterized several gene expression elements and constructed a multiple inducible system that responds to ten different small chemical inducers in halophile bacterium Halomonas bluephagenesis. Genome insertion of regulators was conducted for the purpose of gene cluster stabilization and regulatory plasmid simplification. Additionally, dynamic ranges of the multiple inducible systems were tuned by promoter sequence mutations to achieve diverse scopes for high-resolution gene expression control. The multiple inducible system was successfully employed to precisely control chromoprotein expression, lycopene and poly-3-hydroxybutyrate (PHB) biosynthesis, resulting in colorful bacterial pictures, optimized cell growth, lycopene and PHB accumulation. This study demonstrates a desirable approach for fine-tuning of rational and efficient gene expressions, displaying the significance for metabolic pathway optimization.
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Affiliation(s)
- Yueyuan Ma
- School of Life Sciences, Tsinghua University, Beijing, 100084, China
| | - Jian-Wen Ye
- School of Life Sciences, Tsinghua University, Beijing, 100084, China
| | - Yina Lin
- School of Life Sciences, Tsinghua University, Beijing, 100084, China
| | - Xueqing Yi
- School of Life Sciences, Tsinghua University, Beijing, 100084, China
| | - Xuan Wang
- School of Life Sciences, Tsinghua University, Beijing, 100084, China
| | - Huan Wang
- School of Life Sciences, Tsinghua University, Beijing, 100084, China
| | - Ruiyan Huang
- Garrison Forest School, Owings Mills, MD, 21117, USA
| | - Fuqing Wu
- School of Life Sciences, Tsinghua University, Beijing, 100084, China
| | - Qiong Wu
- School of Life Sciences, Tsinghua University, Beijing, 100084, China
| | - Xu Liu
- PhaBuilder Biotech Co. Ltd., Beijing, 101309, China
| | - Guo-Qiang Chen
- School of Life Sciences, Tsinghua University, Beijing, 100084, China; Center for Synthetic and Systems Biology, Tsinghua University, Beijing, 100084, China; MOE Key Laboratory for Industrial Biocatalysts, Dept Chemical Engineering, Tsinghua University, Beijing, 100084, China; Tsinghua-Peking Center for Life Sciences, Beijing, 100084, China.
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Hernández-Soto LM, Martínez-Abarca F, Ramírez-Saad H, López-Pérez M, Aguirre-Garrido JF. Genome analysis of haloalkaline isolates from the soda saline crater lake of Isabel Island; comparative genomics and potential metabolic analysis within the genus Halomonas. BMC Genomics 2023; 24:696. [PMID: 37986038 PMCID: PMC10662389 DOI: 10.1186/s12864-023-09800-9] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/23/2023] [Accepted: 11/10/2023] [Indexed: 11/22/2023] Open
Abstract
BACKGROUND Isabel Island is a Mexican volcanic island primarily composed of basaltic stones. It features a maar known as Laguna Fragatas, which is classified as a meromictic thalassohaline lake. The constant deposition of guano in this maar results in increased levels of phosphorus, nitrogen, and carbon. The aim of this study was to utilize high-quality genomes from the genus Halomonas found in specialized databases as a reference for genome mining of moderately halophilic bacteria isolated from Laguna Fragatas. This research involved genomic comparisons employing phylogenetic, pangenomic, and metabolic-inference approaches. RESULTS The Halomonas genus exhibited a large open pangenome, but several genes associated with salt metabolism and homeostatic regulation (ectABC and betABC), nitrogen intake through nitrate and nitrite transporters (nasA, and narGI), and phosphorus uptake (pstABCS) were shared among the Halomonas isolates. CONCLUSIONS The isolated bacteria demonstrate consistent adaptation to high salt concentrations, and their nitrogen and phosphorus uptake mechanisms are highly optimized. This optimization is expected in an extremophile environment characterized by minimal disturbances or abrupt seasonal variations. The primary significance of this study lies in the dearth of genomic information available for this saline and low-disturbance environment. This makes it important for ecosystem conservation and enabling an exploration of its biotechnological potential. Additionally, the study presents the first two draft genomes of H. janggokensis.
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Affiliation(s)
- Luis Mario Hernández-Soto
- Doctorado en Ciencias Biológicas y de La Salud, Universidad Autónoma Metropolitana, Mexico City, Mexico
| | - Francisco Martínez-Abarca
- Estructura, Dinámica y Función de Genomas de Rizobacterias, Departamento de Microbiología del Suelo y Sistemas Simbióticos, Estación Experimental del Zaidín-CSIC, Granada, Spain
| | - Hugo Ramírez-Saad
- Departamento Sistemas Biológicos, Universidad Autónoma Metropolitana-Xochimilco, Ciudad de Mexico, México
| | - Marcos López-Pérez
- Departamento de Ciencias Ambientales, Universidad Autónoma Metropolitana-Lerma, Estado de México, Lerma, México
| | - José Félix Aguirre-Garrido
- Departamento de Ciencias Ambientales, Universidad Autónoma Metropolitana-Lerma, Estado de México, Lerma, México.
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11
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Wang Z, Li Y, Gao X, Xing J, Wang R, Zhu D, Shen G. Comparative genomic analysis of Halomonas campaniensis wild-type and ultraviolet radiation-mutated strains reveal genomic differences associated with increased ectoine production. Int Microbiol 2023; 26:1009-1020. [PMID: 37067733 PMCID: PMC10622362 DOI: 10.1007/s10123-023-00356-y] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/01/2022] [Revised: 04/01/2023] [Accepted: 04/05/2023] [Indexed: 04/18/2023]
Abstract
Ectoine is a natural amino acid derivative and one of the most widely used compatible solutes produced by Halomonas species that affects both cellular growth and osmotic equilibrium. The positive effects of UV mutagenesis on both biomass and ectoine content production in ectoine-producing strains have yet to be reported. In this study, the wild-type H. campaniensis strain XH26 (CCTCCM2019776) was subjected to UV mutagenesis to increase ectoine production. Eight rounds of mutagenesis were used to generate mutated XH26 strains with different UV-irradiation exposure times. Ectoine extract concentrations were then evaluated among all strains using high-performance liquid chromatography analysis, alongside whole genome sequencing with the PacBio RS II platform and comparison of the wild-type strain XH26 and the mutant strain G8-52 genomes. The mutant strain G8-52 (CCTCCM2019777) exhibited the highest cell growth rate and ectoine yields among mutated strains in comparison with strain XH26. Further, ectoine levels in the aforementioned strain significantly increased to 1.51 ± 0.01 g L-1 (0.65 g g-1 of cell dry weight), representing a twofold increase compared to wild-type cells (0.51 ± 0.01 g L-1) when grown in culture medium for ectoine accumulation. Concomitantly, electron microscopy revealed that mutated strain G8-52 cells were obviously shorter than wild-type strain XH26 cells. Moreover, strain G8-52 produced a relatively stable ectoine yield (1.50 g L-1) after 40 days of continuous subculture. Comparative genomics analysis suggested that strain XH26 harbored 24 mutations, including 10 nucleotide insertions, 10 nucleotide deletions, and unique single nucleotide polymorphisms. Notably, the genes orf00723 and orf02403 (lipA) of the wild-type strain mutated to davT and gabD in strain G8-52 that encoded for 4-aminobutyrate-2-oxoglutarate transaminase and NAD-dependent succinate-semialdehyde dehydrogenase, respectively. Consequently, these genes may be involved in increased ectoine yields. These results suggest that continuous multiple rounds of UV mutation represent a successful strategy for increasing ectoine production, and that the mutant strain G8-52 is suitable for large-scale fermentation applications.
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Affiliation(s)
- Zhibo Wang
- Research Center of Basic Medical Science, Medical College of Qinghai University, Xining, 810016, China
| | - Yongzhen Li
- Research Center of Basic Medical Science, Medical College of Qinghai University, Xining, 810016, China
| | - Xiang Gao
- Research Center of Basic Medical Science, Medical College of Qinghai University, Xining, 810016, China
| | - Jiangwa Xing
- Research Center of Basic Medical Science, Medical College of Qinghai University, Xining, 810016, China
| | - Rong Wang
- Research Center of Basic Medical Science, Medical College of Qinghai University, Xining, 810016, China
| | - Derui Zhu
- Research Center of Basic Medical Science, Medical College of Qinghai University, Xining, 810016, China
| | - Guoping Shen
- Research Center of Basic Medical Science, Medical College of Qinghai University, Xining, 810016, China.
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12
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Xie Y, Tian X, He Y, Dong S, Zhao K. Nitrogen removal capability and mechanism of a novel heterotrophic nitrification-aerobic denitrification bacterium Halomonas sp. DN3. Bioresour Technol 2023; 387:129569. [PMID: 37517711 DOI: 10.1016/j.biortech.2023.129569] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 06/15/2023] [Revised: 07/23/2023] [Accepted: 07/25/2023] [Indexed: 08/01/2023]
Abstract
Recently, the functional microorganisms capable of eliminating nitrogenous waste have been applied in mariculture systems. As a potential candidate for treating mariculture wastewater, strain DN3 eliminated 100% of ammonia and nitrate and 96.61%-100% of nitrite within 72 h, when single nitrogen sources at concentrations of 0-50 mg/L. Strain DN3 also exhibited the efficient removal performance of mixed-form nitrogen (ammonia, nitrate, and nitrite) at salinity 30 ‰, C/N ratio 20, and 180 rpm. The nitrogen assimilation pathway dominated inorganic nitrogen metabolism, with less nitrogen (14.23%-25.02% of TN) lost into the air via nitrification and denitrification, based on nitrogen balance analysis. Moreover, the bacterial nitrification pathway was explored by enzymatic assays and inhibition assays. These complex nitrogen assimilation and dissimilation processes were further revealed by bacterial genome analysis. These results provide important insight into nitrogen metabolism of Halomonas sp. and theoretical support for treating mariculture wastewater with strain DN3.
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Affiliation(s)
- Yumeng Xie
- The Key Laboratory of Mariculture (Ocean University of China), Ministry of Education, Qingdao 266000, PR China
| | - Xiangli Tian
- The Key Laboratory of Mariculture (Ocean University of China), Ministry of Education, Qingdao 266000, PR China; Function Laboratory for Marine Fisheries Science and Food Production Processes, Qingdao National Laboratory for Marine Science and Technology, Qingdao 266000, PR China.
| | - Yu He
- The Key Laboratory of Mariculture (Ocean University of China), Ministry of Education, Qingdao 266000, PR China
| | - Shuanglin Dong
- The Key Laboratory of Mariculture (Ocean University of China), Ministry of Education, Qingdao 266000, PR China; Function Laboratory for Marine Fisheries Science and Food Production Processes, Qingdao National Laboratory for Marine Science and Technology, Qingdao 266000, PR China
| | - Kun Zhao
- The Key Laboratory of Mariculture (Ocean University of China), Ministry of Education, Qingdao 266000, PR China
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13
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Tang H, Li YQ, Wang MJ, Wang Y, Luo CB. Valorization of lignin-derived compounds into poly(3-hydroxybutyrate-co-3-hydroxyvalerate) by engineered Halomonas sp. Y3. Int J Biol Macromol 2023; 249:126079. [PMID: 37536413 DOI: 10.1016/j.ijbiomac.2023.126079] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/24/2023] [Revised: 07/25/2023] [Accepted: 07/29/2023] [Indexed: 08/05/2023]
Abstract
Poly(3-hydroxybutyrate-co-3-hydroxyvalerate) (PHBV) is a biopolyester with great potential, but its high production cost via the propionate-dependent pathway has hindered its development. Herein, we engineer Halomonas sp. Y3 to achieve efficient conversion of various LDCs into PHBV without propionate supplement. Initially, we successfully achieve PHBV production without propionate supplement by overexpressing threonine synthesis. The resulting biopolyester exhibits a 3 HV proportion of up to 7.89 mol%, comparable to commercial PHBV (8 mol%) available from Sigma Aldrich (403105). To further enhance PHBV production, we rationally design the reconstruction of aromatic compound catabolism. The engineered strain Y3_18 efficiently assimilates all LDCs containing syringyl (S), guaiacyl (G), and p-hydroxyphenyl-type (H) units. From 1 g/L of S-, G-, and H-type LDCs, Y3_18 produces PHBV at levels of 449 mg/L, 488 mg/L, and 716 mg/L, respectively, with yields of 44.9 % (g/g), 48.8 % (g/g), and 71.6 % (g/g). Moreover, to improve PHBV yield from lignin, we integrate laccase-secretion and PHBV production modules. This integration leads to the accumulation of 425.84 mg/L of PHBV with a yield of 21.29 % (g/g) and a 3 HV proportion of 6.38 mol%. By harnessing the capabilities of Halomonas sp. Y3, we demonstrate an efficient and sustainable approach for PHBV production from a variety of LDCs.
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Affiliation(s)
- Hao Tang
- College of Life Science, Leshan Normal University, Leshan 614000, China
| | - Yuan-Qiu Li
- College of Life Science, Leshan Normal University, Leshan 614000, China
| | - Ming-Jun Wang
- College of Life Science, Leshan Normal University, Leshan 614000, China
| | - Yan Wang
- College of Life Science, Leshan Normal University, Leshan 614000, China.
| | - Chao-Bing Luo
- College of Life Science, Leshan Normal University, Leshan 614000, China.
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14
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Zhang L, Lin Y, Yi X, Huang W, Hu Q, Zhang Z, Wu F, Ye JW, Chen GQ. Engineering low-salt growth Halomonas Bluephagenesis for cost-effective bioproduction combined with adaptive evolution. Metab Eng 2023; 79:146-158. [PMID: 37543135 DOI: 10.1016/j.ymben.2023.08.001] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/26/2023] [Revised: 08/01/2023] [Accepted: 08/03/2023] [Indexed: 08/07/2023]
Abstract
Halophilic Halomonas bluephagenesis has been engineered to produce various added-value bio-compounds with reduced costs. However, the salt-stress regulatory mechanism remained unclear. H. bluephagenesis was randomly mutated to obtain low-salt growing mutants via atmospheric and room temperature plasma (ARTP). The resulted H. bluephagenesis TDH4A1B5 was constructed with the chromosomal integration of polyhydroxyalkanoates (PHA) synthesis operon phaCAB and deletion of phaP1 gene encoding PHA synthesis associated protein phasin, forming H. bluephagenesis TDH4A1B5P, which led to increased production of poly(3-hydroxybutyrate) (PHB) and poly(3-hydroxybutyrate-co-4-hydrobutyrate) (P34HB) by over 1.4-fold. H. bluephagenesis TDH4A1B5P also enhanced production of ectoine and threonine by 50% and 77%, respectively. A total 101 genes related to salinity tolerance was identified and verified via comparative genomic analysis among four ARTP mutated H. bluephagenesis strains. Recombinant H. bluephagenesis TDH4A1B5P was further engineered for PHA production utilizing sodium acetate or gluconate as sole carbon source. Over 33% cost reduction of PHA production could be achieved using recombinant H. bluephagenesis TDH4A1B5P. This study successfully developed a low-salt tolerant chassis H. bluephagenesis TDH4A1B5P and revealed salt-stress related genes of halophilic host strains.
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Affiliation(s)
- Lizhan Zhang
- School of Life Sciences, Tsinghua University, Beijing, 100084, China
| | - Yina Lin
- School of Life Sciences, Tsinghua University, Beijing, 100084, China
| | - Xueqing Yi
- School of Life Sciences, Tsinghua University, Beijing, 100084, China
| | - Wuzhe Huang
- PhaBuilder Biotech Co. Ltd., Shunyi District, Zhaoquan Ying, Beijing, 101309, China
| | - Qitiao Hu
- School of Life Sciences, Tsinghua University, Beijing, 100084, China
| | - Zhongnan Zhang
- School of Life Sciences, Tsinghua University, Beijing, 100084, China
| | - Fuqing Wu
- School of Life Sciences, Tsinghua University, Beijing, 100084, China
| | - Jian-Wen Ye
- School of Life Sciences, Tsinghua University, Beijing, 100084, China
| | - Guo-Qiang Chen
- School of Life Sciences, Tsinghua University, Beijing, 100084, China; Center for Synthetic and Systems Biology, Tsinghua University, Beijing, 100084, China; Tsinghua-Peking Center for Life Sciences, Beijing, China; MOE Key Lab of Industrial Biocatalysis, Dept Chemical Engineering, Tsinghua University, Beijing, 100084, China.
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15
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Aytar Celik P, Barut D, Enuh BM, Erdogan Gover K, Nural Yaman B, Burcin Mutlu M, Cabuk A. A novel higher polyhydroxybutyrate producer Halomonas halmophila 18H with unique cell factory attributes. Bioresour Technol 2023; 372:128669. [PMID: 36702321 DOI: 10.1016/j.biortech.2023.128669] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 12/17/2022] [Revised: 01/19/2023] [Accepted: 01/20/2023] [Indexed: 06/18/2023]
Abstract
For cost-competitive biosynthesis of polyhydroxybutyrate (PHB), the screening of efficient producers and characterization of their genomic potential is fundamental. In this study, 94 newly isolated halophilic strains from Turkish salterns were screened for their polyhydroxyalkanoates (PHAs) biosynthesis capabilities through fermentation. Halomonas halmophila 18H was found to be the highest PHB producer, yielding 63.72 % of its biomass as PHB. The PHB produced by this strain was physically and chemically characterized using various techniques. Its genome was also sequenced and found to be large (6,713,657 bp) and have a GC content of 59.9 %. Halomonas halmophila 18H was also found to have several copies of PHB biosynthesis genes, as well as 20 % more protein-coding genes and 1075 singletons compared to other high PHB producers. These unique genomic features make it a promising cell factory for the simultaneous production of PHAs and other biotechnologically important secondary metabolites.
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Affiliation(s)
- Pinar Aytar Celik
- Environmental Protection and Control Program, Eskisehir Osmangazi University, 26110 Eskisehir, Turkey; Department of Biotechnology and Biosafety, Graduate School of Natural and Applied Sciences, Eskisehir Osmangazi University, 26040 Eskisehir, Turkey.
| | - Dilan Barut
- Department of Biotechnology and Biosafety, Graduate School of Natural and Applied Sciences, Eskisehir Osmangazi University, 26040 Eskisehir, Turkey
| | - Blaise Manga Enuh
- Department of Biotechnology and Biosafety, Graduate School of Natural and Applied Sciences, Eskisehir Osmangazi University, 26040 Eskisehir, Turkey
| | - Kubra Erdogan Gover
- Department of Biotechnology and Biosafety, Graduate School of Natural and Applied Sciences, Eskisehir Osmangazi University, 26040 Eskisehir, Turkey
| | - Belma Nural Yaman
- Department of Biotechnology and Biosafety, Graduate School of Natural and Applied Sciences, Eskisehir Osmangazi University, 26040 Eskisehir, Turkey; Department of Biomedical Engineering, Eskisehir Osmangazi University, 26040 Eskisehir, Turkey
| | - Mehmet Burcin Mutlu
- Department of Biology, Faculty of Science, Eskisehir Technical University, Eskisehir, Turkey
| | - Ahmet Cabuk
- Department of Biotechnology and Biosafety, Graduate School of Natural and Applied Sciences, Eskisehir Osmangazi University, 26040 Eskisehir, Turkey; Department of Biology, Faculty of Science, Eskisehir Osmangazi University, Eskisehir, Turkey
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16
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Li YQ, Wang MJ, Luo CB. Highly efficient polyhydroxyalkanoate production from lignin using genetically engineered Halomonas sp. Y3. Bioresour Technol 2023; 370:128526. [PMID: 36572161 DOI: 10.1016/j.biortech.2022.128526] [Citation(s) in RCA: 3] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 11/22/2022] [Revised: 12/20/2022] [Accepted: 12/21/2022] [Indexed: 06/17/2023]
Abstract
Lignin degradation represents a significant challenge in biological valorization, but it is suffering from insufficiency, putting barriers to efficient lignin conversion. Herein, the study first develops a highly efficient laccase secretion apparatus, enabling high enzyme activity of 184 U/mL, complementing the biochemical limits on lignin depolymerization well in Halomonas sp. Y3. Further engineering of PHA biosynthesis produces a significantly high PHA titer of 286, 742, and 868 mg/L from alkaline lignin, catechol, and protocatechuate, respectively. The integration of laccase-secretion and PHA production modules enables a record titer of 693 and 1209 mg/L in converting lignin and lignin-containing stream to PHA, respectively. The titer is improved furtherly to 740 and 1314 mg/L by developing a non-sterilized fermentation. This study advances a cheaper and greener production of valuable chemicals from lignin by constructing a biosynthetic platform for PHA production and provides novel insight into the lignin conversion by extremophilic microbes.
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Affiliation(s)
- Yuan-Qiu Li
- College of Life Science, Leshan Normal University, Leshan 614000, China; College of Life Sciences, Capital Normal University, Beijing 100064, China
| | - Ming-Jun Wang
- College of Life Science, Leshan Normal University, Leshan 614000, China
| | - Chao-Bing Luo
- College of Life Science, Leshan Normal University, Leshan 614000, China.
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17
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Christensen M, Chiciudean I, Jablonski P, Tanase AM, Shapaval V, Hansen H. Towards high-throughput screening (HTS) of polyhydroxyalkanoate (PHA) production via Fourier transform infrared (FTIR) spectroscopy of Halomonas sp. R5-57 and Pseudomonas sp. MR4-99. PLoS One 2023; 18:e0282623. [PMID: 36888636 PMCID: PMC9994712 DOI: 10.1371/journal.pone.0282623] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/10/2022] [Accepted: 02/20/2023] [Indexed: 03/09/2023] Open
Abstract
High-throughput screening (HTS) methods for characterization of microbial production of polyhydroxyalkanoates (PHA) are currently under investigated, despite the advent of such systems in related fields. In this study, phenotypic microarray by Biolog PM1 screening of Halomonas sp. R5-57 and Pseudomonas sp. MR4-99 identified 49 and 54 carbon substrates to be metabolized by these bacteria, respectively. Growth on 15 (Halomonas sp. R5-57) and 14 (Pseudomonas sp. MR4-99) carbon substrates was subsequently characterized in 96-well plates using medium with low nitrogen concentration. Bacterial cells were then harvested and analyzed for putative PHA production using two different Fourier transform infrared spectroscopy (FTIR) systems. The FTIR spectra obtained from both strains contained carbonyl-ester peaks indicative of PHA production. Strain specific differences in the carbonyl-ester peak wavenumber indicated that the PHA side chain configuration differed between the two strains. Confirmation of short chain length PHA (scl-PHA) accumulation in Halomonas sp. R5-57 and medium chain length PHA (mcl-PHA) in Pseudomonas sp. MR4-99 was done using Gas Chromatography-Flame Ionization Detector (GC-FID) analysis after upscaling to 50 mL cultures supplemented with glycerol and gluconate. The strain specific PHA side chain configurations were also found in FTIR spectra of the 50 mL cultures. This supports the hypothesis that PHA was also produced in the cells cultivated in 96-well plates, and that the HTS approach is suitable for analysis of PHA production in bacteria. However, the carbonyl-ester peaks detected by FTIR are only indicative of PHA production in the small-scale cultures, and appropriate calibration and prediction models based on combining FTIR and GC-FID data needs to be developed and optimized by performing more extensive screenings and multivariate analyses.
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Affiliation(s)
- Mikkel Christensen
- Department of Chemistry, UiT The Arctic University of Norway, Tromso, Norway
- * E-mail: (MC); (HH)
| | - Iulia Chiciudean
- Department of Genetics, Faculty of Biology, University of Bucharest, Bucharest, Romania
| | | | - Ana-Maria Tanase
- Department of Genetics, Faculty of Biology, University of Bucharest, Bucharest, Romania
| | - Volha Shapaval
- Faculty of Science and Technology, Norwegian University of Life Sciences, Aas, Norway
| | - Hilde Hansen
- Department of Chemistry, UiT The Arctic University of Norway, Tromso, Norway
- * E-mail: (MC); (HH)
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18
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Tang H, Wang MJ, Gan XF, Li YQ. Funneling lignin-derived compounds into polyhydroxyalkanoate by Halomonas sp. Y3. Bioresour Technol 2022; 362:127837. [PMID: 36031122 DOI: 10.1016/j.biortech.2022.127837] [Citation(s) in RCA: 10] [Impact Index Per Article: 5.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 07/19/2022] [Revised: 08/21/2022] [Accepted: 08/22/2022] [Indexed: 06/15/2023]
Abstract
Lignin-derived compounds (LDCs) biological funneling for polyhydroxyalkanoate (PHA) synthesis has been attractive but elusive. Herein, the Halomonas sp. Y3 is isolated and developed for PHA production from LDCs. Of the tested 13 LDCs, 4-hydroxybenzoic acid (4-HBA), protocatechuate (PA), catechol (CAT), and vanillic acid (VA) exhibit a hyper-degradation and production with 87.2 %, 85.8 %, 84.7 %, and 83.4 % TOC removal rate and 535.2 mg/L, 506.5 mg/L, 435.6 mg/L, and 440.8 mg/L PHA concentration, respectively. The Halomonas sp. Y3 genome is sequenced by identifying numerous genes responsible for LDCs funneling, stress response, and PHA biosynthesis. An open unsterilized fermentation with optimal conditions of pH 9.0 and NaCl 60 g/L is investigated, achieving a completely aseptic effect and significantly improved PHA production from LDCs. Overall, the results indicate that the Halomonas sp. Y3 is an ideal candidate for LDC bioconversion and exhibits a great potential to realize black liquor valorization.
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Affiliation(s)
- Hao Tang
- Bamboo Diseases and Pests Control and Resources Development Key Laboratory of Sichuan Province, Leshan Normal University, Leshan 614000, China
| | - Ming-Jun Wang
- Bamboo Diseases and Pests Control and Resources Development Key Laboratory of Sichuan Province, Leshan Normal University, Leshan 614000, China
| | - Xiao-Feng Gan
- Bamboo Diseases and Pests Control and Resources Development Key Laboratory of Sichuan Province, Leshan Normal University, Leshan 614000, China
| | - Yuan-Qiu Li
- Bamboo Diseases and Pests Control and Resources Development Key Laboratory of Sichuan Province, Leshan Normal University, Leshan 614000, China; College of Life Sciences, Capital Normal University, Beijing 100048, China.
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19
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Zhang L, Ye JW, Zhang X, Huang W, Zhang Z, Lin Y, Zhang G, Wu F, Wang Z, Wu Q, Chen GQ. Effective production of Poly(3-hydroxybutyrate-co-4-hydroxybutyrate) by engineered Halomonas bluephagenesis grown on glucose and 1,4-Butanediol. Bioresour Technol 2022; 355:127270. [PMID: 35526716 DOI: 10.1016/j.biortech.2022.127270] [Citation(s) in RCA: 5] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 04/10/2022] [Revised: 05/01/2022] [Accepted: 05/02/2022] [Indexed: 06/14/2023]
Abstract
Halomonas bluephagenesis has been engineered to produce flexible copolymers P34HB or poly(3-hydroxybutyrate-co-4-hydroxybutyrate) from glucose and petrol-chemical precursor, γ-butyrolactone. Herein, gene cluster aldD-dhaT was constructed in recombinant H. bluephagenesis for catalyzing 1,4-butanediol (BDO) into 4-hydroxybutyrate, which could grow to 86 g L-1 dry cell mass (DCM) containing 77 wt% P(3HB-co-14 mol% 4HB) in 7-L bioreactor fed with glucose and bio-based BDO. Furthermore, 4HB monomer ratio could be increased to 16 mol% by engineered H. bluephagenesis TDH4-WZY254 with defected outer-membrane. Upon deletion of 4HB degradation pathway, followed by aldD-dhaT integration, the resulted H. bluephagenesis TDB141ΔAC was grown to 95 g L-1 DCM containing 79 wt% P(3HB-co-14 mol% 4HB) with a BDO conversion efficiency of 86% under fed-batch fermentation. Notably, 4HB molar ratio can be significantly improved to 21 mol% with negligible effects on cell growth and P34HB synthesis by adding 50% more BDO. This study successfully demonstrated a fully bio-based P34HB effectively produced by H. bluephagenesis.
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Affiliation(s)
- Lizhan Zhang
- School of Life Sciences, Tsinghua University, Beijing 100084, China
| | - Jian-Wen Ye
- School of Biology and Biological Engineering, South China University of Technology, Guangzhou 510006, China; Guangdong Key Laboratory of Fermentation and Enzyme Engineering, School of Biology and Biological Engineering, South China University of Technology, Guangzhou, China; Guangdong Research Center of Industrial Enzyme and Green Manufacturing Technology, School of Biology and Biological Engineering, South China University of Technology, Guangzhou, China
| | - Xu Zhang
- School of Life Sciences, Tsinghua University, Beijing 100084, China; PhaBuilder Biotech Co. Ltd., Shunyi District, Zhaoquan Ying, Beijing 101309, China; Tsinghua-Peking Center for Life Sciences, Beijing, China
| | - Wuzhe Huang
- PhaBuilder Biotech Co. Ltd., Shunyi District, Zhaoquan Ying, Beijing 101309, China
| | - Zhongnan Zhang
- School of Life Sciences, Tsinghua University, Beijing 100084, China
| | - Yina Lin
- School of Life Sciences, Tsinghua University, Beijing 100084, China; Center for Synthetic and Systems Biology, Tsinghua University, Beijing 100084, China; Tsinghua-Peking Center for Life Sciences, Beijing, China
| | - Ge Zhang
- School of Life Sciences, Tsinghua University, Beijing 100084, China
| | - Fuqing Wu
- School of Life Sciences, Tsinghua University, Beijing 100084, China
| | - Ziyu Wang
- School of Life Sciences, Tsinghua University, Beijing 100084, China
| | - Qiong Wu
- School of Life Sciences, Tsinghua University, Beijing 100084, China
| | - Guo-Qiang Chen
- School of Life Sciences, Tsinghua University, Beijing 100084, China; Center for Synthetic and Systems Biology, Tsinghua University, Beijing 100084, China; PhaBuilder Biotech Co. Ltd., Shunyi District, Zhaoquan Ying, Beijing 101309, China; Tsinghua-Peking Center for Life Sciences, Beijing, China.
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Zhao C, Zheng T, Feng Y, Wang X, Zhang L, Hu Q, Chen J, Wu F, Chen GQ. Engineered Halomonas spp. for production of l-Lysine and cadaverine. Bioresour Technol 2022; 349:126865. [PMID: 35183730 DOI: 10.1016/j.biortech.2022.126865] [Citation(s) in RCA: 13] [Impact Index Per Article: 6.5] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 01/26/2022] [Revised: 02/12/2022] [Accepted: 02/14/2022] [Indexed: 06/14/2023]
Abstract
Cadaverine, a derivative of l-lysine, has been used as a monomer for the synthesis of bio-based nylon-5,6. This study engineered Halomonas bluephagenesis TD1.0 by blocking the feedback inhibition, overexpressing the key l-lysine synthesis genes, strengthening the l-lysine export system and increasing the supply of oxaloacetate for production of l-lysine in the supernatant and PHB in the cells. Subsequently, cadaverine biosynthetic pathway was constructed in H. campaniensis LC-9 to improve the efficiency of de novo cadaverine biosynthesis which combines l-lysine producing H. bluephagenesis TDL8-68-259 and cadaverine producing H. campaniensis LC-9-ldcC-lysP. When H. campaniensis LC-9-ldcC-lysP was used as a whole cell catalysis for cadaverine production, the conversion efficiency of l-lysine to cadaverine reached 100% in the presence of 0.05% Triton X-100 for cell membrane permeability enhancement, resulting in 118 g L-1 cadaverine formed in the fermentor. Thus, Halomonas spp. have been successfully constructed for l-lysine and cadaverine production.
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Affiliation(s)
- Cuihuan Zhao
- Center for Synthetic and Systems Biology, School of Life Sciences, Tsinghua University, Beijing 100084, PR China; Tsinghua-Peking Center for Life Sciences, Beijing 100084, PR China
| | - Taoran Zheng
- Center for Synthetic and Systems Biology, School of Life Sciences, Tsinghua University, Beijing 100084, PR China; Beijing PhaBuilder Biotechnology Co., LTD, Shunyi District, 101399, PR China
| | - Yinghao Feng
- Center for Synthetic and Systems Biology, School of Life Sciences, Tsinghua University, Beijing 100084, PR China
| | - Xuan Wang
- Center for Synthetic and Systems Biology, School of Life Sciences, Tsinghua University, Beijing 100084, PR China; Tsinghua-Peking Center for Life Sciences, Beijing 100084, PR China
| | - Lizhan Zhang
- Center for Synthetic and Systems Biology, School of Life Sciences, Tsinghua University, Beijing 100084, PR China
| | - Qitiao Hu
- Center for Synthetic and Systems Biology, School of Life Sciences, Tsinghua University, Beijing 100084, PR China
| | - Jinchun Chen
- Center for Synthetic and Systems Biology, School of Life Sciences, Tsinghua University, Beijing 100084, PR China
| | - Fuqing Wu
- Center for Synthetic and Systems Biology, School of Life Sciences, Tsinghua University, Beijing 100084, PR China; MOE Key Lab of Industrial Biocatalysts, Department of Chemical Engineering, Tsinghua University, Beijing 100084, PR China
| | - Guo-Qiang Chen
- Center for Synthetic and Systems Biology, School of Life Sciences, Tsinghua University, Beijing 100084, PR China; Tsinghua-Peking Center for Life Sciences, Beijing 100084, PR China; MOE Key Lab of Industrial Biocatalysts, Department of Chemical Engineering, Tsinghua University, Beijing 100084, PR China.
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21
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Cheffi M, Maalej A, Mahmoudi A, Hentati D, Marques AM, Sayadi S, Chamkha M. Lipopeptides production by a newly Halomonas venusta strain: Characterization and biotechnological properties. Bioorg Chem 2021; 109:104724. [PMID: 33618256 DOI: 10.1016/j.bioorg.2021.104724] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/26/2020] [Revised: 01/30/2021] [Accepted: 02/02/2021] [Indexed: 11/26/2022]
Abstract
A halotolerant marine strain PHKT of Halomonas venusta was isolated from contaminated seawater as an efficient biosurfactant producer candidate, on low-value substrate (glycerol). The produced biosurfactants (Bios-PHKT) were characterized as lipopeptides molecules, belonging to surfactin and pumilacidin families, by using Thin Layer Chromatography (TLC), Fourier Transform Infrared Spectroscopy (FT-IR) and Tandem Mass Spectrometry (MALDI-TOF/MS-MS). Bios-PHKT has a critical micelle concentration (CMC) of 125 mg/L, and showed a high steadiness against a wide spectrum of salinity (0-120 g/L NaCl), temperature (4-121 °C) and pH (2-12), supporting its powerful tensioactive properties under various environmental conditions. Likewise, the cytotoxic test revealed that the biosurfactant Bios-PHKT, at concentrations lower than 125 µg/mL, was not cytotoxic for human HEK-293 cells since the cell survival is over than 80%. Furthermore, Bios-PHKT lipopeptides showed excellent anti-adhesive and anti-biofilm activities, being able to avoid and disrupt the biofilm formation by certain pathogenic microorganisms. In addition, the biosurfactant Bios-PHKT showed a remarkable anti-proliferative activity towards tumor B16 melanoma cell line. Besides, Bios-PHKT exhibited an excellent in vitro and in vivo wound healing process. In light of these promising findings, Bios-PHKT could be successfully used in different biotechnological applications.
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Affiliation(s)
- Meriam Cheffi
- Laboratory of Environmental Bioprocesses, Centre of Biotechnology of Sfax, University of Sfax, PO Box 1177, 3018 Sfax, Tunisia
| | - Amina Maalej
- Laboratory of Environmental Bioprocesses, Centre of Biotechnology of Sfax, University of Sfax, PO Box 1177, 3018 Sfax, Tunisia
| | - Asma Mahmoudi
- Laboratory of Environmental Bioprocesses, Centre of Biotechnology of Sfax, University of Sfax, PO Box 1177, 3018 Sfax, Tunisia
| | - Dorra Hentati
- Laboratory of Environmental Bioprocesses, Centre of Biotechnology of Sfax, University of Sfax, PO Box 1177, 3018 Sfax, Tunisia
| | - Ana Maria Marques
- Section of Microbiology, Department of Biology, Health and Environment, Faculty of Pharmacy, University of Barcelona, Joan XXIII s/n, 08028 Barcelona, Spain
| | - Sami Sayadi
- Centre for Sustainable Development, College of Arts and Sciences, Qatar University, Doha 2713, Qatar.
| | - Mohamed Chamkha
- Laboratory of Environmental Bioprocesses, Centre of Biotechnology of Sfax, University of Sfax, PO Box 1177, 3018 Sfax, Tunisia.
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22
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Abstract
3-Hydroxypropionic acid (3HP), an important three carbon (C3) chemical, is designated as one of the top platform chemicals with an urgent need for improved industrial production. Halomonas bluephagenesis shows the potential as a chassis for competitive bioproduction of various chemicals due to its ability to grow under an open, unsterile and continuous process. Here, we report the strategy for producing 3HP and its copolymer poly(3-hydroxybutyrate-co-3-hydroxypropionate) (P3HB3HP) by the development of H. bluephagenesis. The transcriptome analysis reveals its 3HP degradation and synthesis pathways involving endogenous synthetic enzymes from 1,3-propanediol. Combing the optimized expression of aldehyde dehydrogenase (AldDHb), an engineered H. bluephagenesis strain of whose 3HP degradation pathway is deleted and that overexpresses alcohol dehydrogenases (AdhP) on its genome under a balanced redox state, is constructed with an enhanced 1.3-propanediol-dependent 3HP biosynthetic pathway to produce 154 g L-1 of 3HP with a yield and productivity of 0.93 g g-1 1,3-propanediol and 2.4 g L-1 h-1, respectively. Moreover, the strain could also accumulate 60% poly(3-hydroxybutyrate-co-32-45% 3-hydroxypropionate) in the dry cell mass, demonstrating to be a suitable chassis for hyperproduction of 3HP and P3HB3HP.
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Affiliation(s)
- Xiao-Ran Jiang
- Department of Microbiology, Army Medical University, Chongqing, China
- School of Life Sciences, Tsinghua University, Beijing, China
| | - Xu Yan
- School of Life Sciences, Tsinghua University, Beijing, China
- Center for Synthetic and Systems Biology, School of Life Sciences, Tsinghua University, Beijing, China
| | - Lin-Ping Yu
- School of Life Sciences, Tsinghua University, Beijing, China
| | - Xin-Yi Liu
- School of Life Sciences, Tsinghua University, Beijing, China
- Center for Synthetic and Systems Biology, School of Life Sciences, Tsinghua University, Beijing, China
| | - Guo-Qiang Chen
- School of Life Sciences, Tsinghua University, Beijing, China.
- Center for Synthetic and Systems Biology, School of Life Sciences, Tsinghua University, Beijing, China.
- MOE Key Lab for Industrial Biocatalysis, Department of Chemical Engineering, Tsinghua University, Beijing, China.
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23
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Li S, Shang Y, Zhao Q, Liu Y, Dong X, Wang W, Yang C. Promoter engineering for high ectoine production in a lower saline medium by Halomonas hydrothermalis Y2. Biotechnol Lett 2021; 43:825-834. [PMID: 33502660 DOI: 10.1007/s10529-021-03084-3] [Citation(s) in RCA: 7] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/02/2020] [Accepted: 01/13/2021] [Indexed: 11/26/2022]
Abstract
OBJECTIVES For the stress from fermenters, downstream processing equipment, and wastewater treatment to be alleviated, lowering salt-dependence in the ectoine synthesis process is of great significance in the moderately halotolerant Halomonas hydrothermalis Y2. RESULTS In H. hydrothermalis Y2, the σ70- and σ38-controlled promoters of ectA are predicted to be involved in the osmotic regulation of ectoine synthesis. By substituting the ectA promoter with a promoter P265 that identified in the outer membrane pore protein E of H. hydrothermalis Y2, the salt dependence of ectoine synthesis was significantly decreased. In the 500-ml flask containing various NaCl contents, the engineered strain (p/Y2/△ectD/△doeA) showed a remarkably enhanced ability in ectoine synthesis, especially under lower saline stress. After a 36-h fed-batch fermentation in the 1-l fermenter, p/Y2/△ectD/△doeA synthesized 11.5 g ectoine l-1 in the presence of 60 g NaCl-1 l, with a high 0.32 g ectoine l-1 h-1 productivity, a specific productivity of 512.2 mg ectoine per g cell dry weight (CDW)-1, and an excretion ratio of 67 % ectoine. CONCLUSIONS As no impaired growth was observed in strain p/Y2/△ectD/△doeA while ectoine synthesis was increased, this promoter engineering strategy provides a practical protocol for lowering the salt-dependence of ectoine synthesis in this moderately halotolerant strain.
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Affiliation(s)
- Shannan Li
- State Key Laboratory of Microbial Technology, Institute of Microbial Technology, Shandong University, Qingdao, 266237, People's Republic of China
| | - Yan Shang
- State Key Laboratory of Microbial Technology, Institute of Microbial Technology, Shandong University, Qingdao, 266237, People's Republic of China
| | - Qi Zhao
- State Key Laboratory of Microbial Technology, Institute of Microbial Technology, Shandong University, Qingdao, 266237, People's Republic of China
| | - Yuanxiang Liu
- State Key Laboratory of Microbial Technology, Institute of Microbial Technology, Shandong University, Qingdao, 266237, People's Republic of China
| | - Xueqian Dong
- State Key Laboratory of Microbial Technology, Institute of Microbial Technology, Shandong University, Qingdao, 266237, People's Republic of China
| | - Wenkai Wang
- State Key Laboratory of Microbial Technology, Institute of Microbial Technology, Shandong University, Qingdao, 266237, People's Republic of China
| | - Chunyu Yang
- State Key Laboratory of Microbial Technology, Institute of Microbial Technology, Shandong University, Qingdao, 266237, People's Republic of China.
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24
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Athmika, Ghate SD, Arun AB, Rao SS, Kumar STA, Kandiyil MK, Saptami K, Rekha PD. Genome analysis of a halophilic bacterium Halomonas malpeensis YU-PRIM-29 T reveals its exopolysaccharide and pigment producing capabilities. Sci Rep 2021; 11:1749. [PMID: 33462335 PMCID: PMC7814019 DOI: 10.1038/s41598-021-81395-1] [Citation(s) in RCA: 9] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/12/2020] [Accepted: 01/04/2021] [Indexed: 11/08/2022] Open
Abstract
Halomonas malpeensis strain YU-PRIM-29T is a yellow pigmented, exopolysaccharide (EPS) producing halophilic bacterium isolated from the coastal region. To understand the biosynthesis pathways involved in the EPS and pigment production, whole genome analysis was performed. The complete genome sequencing and the de novo assembly were carried out using Illumina sequencing and SPAdes genome assembler (ver 3.11.1) respectively followed by detailed genome annotation. The genome consists of 3,607,821 bp distributed in 18 contigs with 3337 protein coding genes and 53% of the annotated CDS are having putative functions. Gene annotation disclosed the presence of genes involved in ABC transporter-dependent pathway of EPS biosynthesis. As the ABC transporter-dependent pathway is also implicated in the capsular polysaccharide (CPS) biosynthesis, we employed extraction protocols for both EPS (from the culture supernatants) and CPS (from the cells) and found that the secreted polysaccharide i.e., EPS was predominant. The EPS showed good emulsifying activities against the petroleum hydrocarbons and its production was dependent on the carbon source supplied. The genome analysis also revealed genes involved in industrially important metabolites such as zeaxanthin pigment, ectoine and polyhydroxyalkanoate (PHA) biosynthesis. To confirm the genome data, we extracted these metabolites from the cultures and successfully identified them. The pigment extracted from the cells showed the distinct UV-Vis spectra having characteristic absorption peak of zeaxanthin (λmax 448 nm) with potent antioxidant activities. The ability of H. malpeensis strain YU-PRIM-29T to produce important biomolecules makes it an industrially important bacterium.
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Affiliation(s)
- Athmika
- Yenepoya Research Centre, Yenepoya (Deemed to be University), University Road, Deralakatte, Mangalore, 575018, India
| | - Sudeep D Ghate
- Yenepoya Research Centre, Yenepoya (Deemed to be University), University Road, Deralakatte, Mangalore, 575018, India
| | - A B Arun
- Yenepoya Research Centre, Yenepoya (Deemed to be University), University Road, Deralakatte, Mangalore, 575018, India
| | - Sneha S Rao
- Yenepoya Research Centre, Yenepoya (Deemed to be University), University Road, Deralakatte, Mangalore, 575018, India
| | - S T Arun Kumar
- Yenepoya Research Centre, Yenepoya (Deemed to be University), University Road, Deralakatte, Mangalore, 575018, India
| | - Mrudula Kinarulla Kandiyil
- Yenepoya Research Centre, Yenepoya (Deemed to be University), University Road, Deralakatte, Mangalore, 575018, India
| | - Kanekar Saptami
- Yenepoya Research Centre, Yenepoya (Deemed to be University), University Road, Deralakatte, Mangalore, 575018, India
| | - P D Rekha
- Yenepoya Research Centre, Yenepoya (Deemed to be University), University Road, Deralakatte, Mangalore, 575018, India.
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25
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Zhai L, Xie J, Feng H, Sun S, Cheng K, Yao S. Mechanism of TonB-dependent transport system in Halomonas alkalicola CICC 11012s in response to alkaline stress. Extremophiles 2020; 25:39-49. [PMID: 33123748 DOI: 10.1007/s00792-020-01209-6] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/09/2020] [Accepted: 10/14/2020] [Indexed: 11/25/2022]
Abstract
Halomonas alkalicola CICC 11012s can grow at pH 12.5, the highest pH at which the organisms in the genus Halomonas can grow. Genomic analysis reveals that H. alkalicola adapts to alkaline stress using a variety of adaptive strategies; however, the detailed mechanism for its growth at high-alkaline conditions has not been elucidated. Therefore, in this study, the adaptations of H. alkalicola in response to extreme alkaline stress were investigated. A sharp decrease of alkaliphilic tolerance was observed in mutants E. coli ΔEctonB and H. alkalicola ΔHatonB. Expressions of the gene clusters encoding TonB-dependent transport system and iron complex transport system in H. alkalicola grown under extreme alkaline conditions were markedly up-regulated. We then compared the intracellular ionic iron content and iron-chelating ability of mutant strain with those of wild-type strain to understand the influence of TonB-dependent transport system on the alkaline responses. The results indicated that the presence of TonB-dependent transport system increased the alkaline tolerance of H. alkalicola grown at high-alkaline conditions, but had no effects when the strain was grown at neutral pH and low-alkaline conditions. Meanwhile, the presence of this system increased the transport and accumulation of ionic irons to maintain intracellular metabolic homeostasis, which in turn could increase the tolerance of the strain to extreme alkaline conditions. Based on the results, we established a model representing the interactions between TonB-dependent transport system, alkaline tolerance, and intracellular ionic iron that could help deepen the understanding of the alkaline response mechanism of alkaliphilic bacteria.
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Affiliation(s)
- Lei Zhai
- China Center of Industrial Culture Collection (CICC), China National Research Institute of Food and Fermentation Industries, Building 6, No. 24 Yard, Jiuxianqiao Middle Road, Chaoyang District, Beijing, China
| | - Jiuyan Xie
- China Center of Industrial Culture Collection (CICC), China National Research Institute of Food and Fermentation Industries, Building 6, No. 24 Yard, Jiuxianqiao Middle Road, Chaoyang District, Beijing, China
| | - Huijun Feng
- China Center of Industrial Culture Collection (CICC), China National Research Institute of Food and Fermentation Industries, Building 6, No. 24 Yard, Jiuxianqiao Middle Road, Chaoyang District, Beijing, China
| | - Sijia Sun
- China Center of Industrial Culture Collection (CICC), China National Research Institute of Food and Fermentation Industries, Building 6, No. 24 Yard, Jiuxianqiao Middle Road, Chaoyang District, Beijing, China
| | - Kun Cheng
- China Center of Industrial Culture Collection (CICC), China National Research Institute of Food and Fermentation Industries, Building 6, No. 24 Yard, Jiuxianqiao Middle Road, Chaoyang District, Beijing, China
| | - Su Yao
- China Center of Industrial Culture Collection (CICC), China National Research Institute of Food and Fermentation Industries, Building 6, No. 24 Yard, Jiuxianqiao Middle Road, Chaoyang District, Beijing, China.
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26
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Lu P, Wang W, Zhang G, Li W, Jiang A, Cao M, Zhang X, Xing K, Peng X, Yuan B, Feng Z. Isolation and characterization marine bacteria capable of degrading lignin-derived compounds. PLoS One 2020; 15:e0240187. [PMID: 33027312 PMCID: PMC7540876 DOI: 10.1371/journal.pone.0240187] [Citation(s) in RCA: 9] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/25/2019] [Accepted: 09/22/2020] [Indexed: 11/30/2022] Open
Abstract
Lignin, a characteristic component of terrestrial plants. Rivers transport large amounts of vascular plant organic matter into the oceans where lignin can degrade over time; however, microorganisms involved in this degradation have not been identified. In this study, several bacterial strains were isolated from marine samples using the lignin-derived compound vanillic acid (4-hydroxy-3-methoxybenzoic acid) as the sole carbon and energy source. The optimum growth temperature for all isolates ranged from 30 to 35°C. All isolates grew well in a wide NaCl concentration range of 0 to over 50 g/L, with an optimum concentration of 22.8 g/L, which is the same as natural seawater. Phylogenetic analysis indicates that these strains are the members of Halomonas, Arthrobacter, Pseudoalteromonas, Marinomonas, and Thalassospira. These isolates are also able to use other lignin-derived compounds, such as 4-hydroxybenzoic acid, ferulic acid, syringic acid, and benzoic acid. Vanillic acid was detected in all culture media when isolates were grown on ferulic acid as the sole carbon source; however, no 4-hydroxy-3-methoxystyrene was detected, indicating that ferulic acid metabolism by these strains occurs via the elimination of two side chain carbons. Furthermore, the isolates exhibit 3,4-dioxygenase or 4,5-dioxygenase activity for protocatechuic acid ring-cleavage, which is consistent with the genetic sequences of related genera. This study was conducted to isolate and characterize marine bacteria of degrading lignin-derived compounds, thereby revealing the degradation of aromatic compounds in the marine environment and opening up new avenues for the development and utilization of marine biological resources.
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Affiliation(s)
- Peng Lu
- College of Life Sciences, Anhui Normal University, Wuhu, China
| | - Weinan Wang
- School of Life Sciences, Jiangsu Normal University, Xuzhou, China
| | - Guangxi Zhang
- School of Life Sciences, Jiangsu Normal University, Xuzhou, China
| | - Wen Li
- School of Life Sciences, Jiangsu Normal University, Xuzhou, China
| | - Anjie Jiang
- School of Life Sciences, Jiangsu Normal University, Xuzhou, China
| | - Mengjiao Cao
- School of Life Sciences, Jiangsu Normal University, Xuzhou, China
| | - Xiaoyan Zhang
- School of Life Sciences, Jiangsu Normal University, Xuzhou, China
| | - Ke Xing
- School of Life Sciences, Jiangsu Normal University, Xuzhou, China
| | - Xue Peng
- School of Life Sciences, Jiangsu Normal University, Xuzhou, China
| | - Bo Yuan
- School of Life Sciences, Jiangsu Normal University, Xuzhou, China
- * E-mail: (BY); (ZF)
| | - Zhaozhong Feng
- School of Life Sciences, Jiangsu Normal University, Xuzhou, China
- * E-mail: (BY); (ZF)
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27
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Chen PW, Cui ZY, Ng HS, Chi-Wei Lan J. Exploring the additive bio-agent impacts upon ectoine production by Halomonas salina DSM5928 T using corn steep liquor and soybean hydrolysate as nutrient supplement. J Biosci Bioeng 2020; 130:195-199. [PMID: 32370929 DOI: 10.1016/j.jbiosc.2020.03.011] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/28/2019] [Revised: 02/27/2020] [Accepted: 03/21/2020] [Indexed: 11/20/2022]
Abstract
Ectoine production using inexpensive and renewable biomass resources has attracted great interest among the researchers due to the low yields of ectoine in current fermentation approaches that complicate the large-scale production of ectoine. In this study, ectoine was produced from corn steep liquor (CSL) and soybean hydrolysate (SH) in replacement to yeast extract as the nitrogen sources for the fermentation process. To enhance the bacterial growth and ectoine production, biotin was added to the Halomonas salina fermentation media. In addition, the effects addition of surfactants such as Tween 80 and saponin on the ectoine production were also investigated. Results showed that both the CSL and SH can be used as the nitrogen source substitutes in the fermentation media. Higher amount of ectoine (1781.9 mg L-1) was produced in shake flask culture with SH-containing media as compared to CSL-containing media. A total of 2537.0 mg L-1 of ectoine was produced at pH 7 when SH-containing media was applied in the 2 L batch fermentation. Moreover, highest amount of ectoine (1802.0 mg L-1) was recorded in the SH-containing shake flask culture with addition of 0.2 μm mL-1 biotin. This study demonstrated the efficacy of industrial waste as the nutrient supplement for the fermentation of ectoine production.
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Affiliation(s)
- Po-Wei Chen
- Biorefinery and Bioprocess Engineering Laboratory, Department of Chemical Engineering and Materials Science, Yuan Ze University, Taoyuan 32003, Taiwan
| | - Zi-Yu Cui
- Biorefinery and Bioprocess Engineering Laboratory, Department of Chemical Engineering and Materials Science, Yuan Ze University, Taoyuan 32003, Taiwan
| | - Hui Suan Ng
- Faculty of Applied Sciences, UCSI University, UCSI Heights, Cheras, Kuala Lumpur 56000, Malaysia
| | - John Chi-Wei Lan
- Biorefinery and Bioprocess Engineering Laboratory, Department of Chemical Engineering and Materials Science, Yuan Ze University, Taoyuan 32003, Taiwan; Graduate School of Biotechnology and Bioengineering, Yuan Ze University, Taoyuan 32003, Taiwan.
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28
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Mais CN, Hermann L, Altegoer F, Seubert A, Richter AA, Wernersbach I, Czech L, Bremer E, Bange G. Degradation of the microbial stress protectants and chemical chaperones ectoine and hydroxyectoine by a bacterial hydrolase-deacetylase complex. J Biol Chem 2020; 295:9087-9104. [PMID: 32404365 PMCID: PMC7335791 DOI: 10.1074/jbc.ra120.012722] [Citation(s) in RCA: 11] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/19/2020] [Revised: 05/06/2020] [Indexed: 12/12/2022] Open
Abstract
When faced with increased osmolarity in the environment, many bacterial cells accumulate the compatible solute ectoine and its derivative 5-hydroxyectoine. Both compounds are not only potent osmostress protectants, but also serve as effective chemical chaperones stabilizing protein functionality. Ectoines are energy-rich nitrogen and carbon sources that have an ecological impact that shapes microbial communities. Although the biochemistry of ectoine and 5-hydroxyectoine biosynthesis is well understood, our understanding of their catabolism is only rudimentary. Here, we combined biochemical and structural approaches to unravel the core of ectoine and 5-hydroxy-ectoine catabolisms. We show that a conserved enzyme bimodule consisting of the EutD ectoine/5-hydroxyectoine hydrolase and the EutE deacetylase degrades both ectoines. We determined the high-resolution crystal structures of both enzymes, derived from the salt-tolerant bacteria Ruegeria pomeroyi and Halomonas elongata These structures, either in their apo-forms or in forms capturing substrates or intermediates, provided detailed insights into the catalytic cores of the EutD and EutE enzymes. The combined biochemical and structural results indicate that the EutD homodimer opens the pyrimidine ring of ectoine through an unusual covalent intermediate, N-α-2 acetyl-l-2,4-diaminobutyrate (α-ADABA). We found that α-ADABA is then deacetylated by the zinc-dependent EutE monomer into diaminobutyric acid (DABA), which is further catabolized to l-aspartate. We observed that the EutD-EutE bimodule synthesizes exclusively the α-, but not the γ-isomers of ADABA or hydroxy-ADABA. Of note, α-ADABA is known to induce the MocR/GabR-type repressor EnuR, which controls the expression of many ectoine catabolic genes clusters. We conclude that hydroxy-α-ADABA might serve a similar function.
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Affiliation(s)
- Christopher-Nils Mais
- Philipps-University Marburg, Center for Synthetic Microbiology (SYNMIKRO) & Faculty of Chemistry, Marburg, Germany
| | - Lucas Hermann
- Philipps-University Marburg, Center for Synthetic Microbiology (SYNMIKRO) & Faculty of Biology, Marburg, Germany
| | - Florian Altegoer
- Philipps-University Marburg, Center for Synthetic Microbiology (SYNMIKRO) & Faculty of Chemistry, Marburg, Germany
| | - Andreas Seubert
- Philipps-University Marburg, Faculty of Chemistry, Marburg, Germany
| | - Alexandra A Richter
- Philipps-University Marburg, Center for Synthetic Microbiology (SYNMIKRO) & Faculty of Biology, Marburg, Germany
| | - Isa Wernersbach
- Philipps-University Marburg, Center for Synthetic Microbiology (SYNMIKRO) & Faculty of Chemistry, Marburg, Germany
| | - Laura Czech
- Philipps-University Marburg, Center for Synthetic Microbiology (SYNMIKRO) & Faculty of Biology, Marburg, Germany
| | - Erhard Bremer
- Philipps-University Marburg, Center for Synthetic Microbiology (SYNMIKRO) & Faculty of Biology, Marburg, Germany.
| | - Gert Bange
- Philipps-University Marburg, Center for Synthetic Microbiology (SYNMIKRO) & Faculty of Chemistry, Marburg, Germany.
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29
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Reshetnikov AS, Rozova ON, Trotsenko YA, But SY, Khmelenina VN, Mustakhimov II. Ectoine degradation pathway in halotolerant methylotrophs. PLoS One 2020; 15:e0232244. [PMID: 32353000 PMCID: PMC7192451 DOI: 10.1371/journal.pone.0232244] [Citation(s) in RCA: 12] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/05/2019] [Accepted: 04/10/2020] [Indexed: 12/03/2022] Open
Abstract
Background Microorganisms living in saline environments are forced to regulate turgor via the synthesis of organic osmoprotective compounds. Microbial adaptation to fluctuations in external salinity includes degradation of compatible solutes. Here we have examined the biochemical pathway of degradation of the cyclic imino acid ectoine, the major osmoprotector in halotolerant methane-utilizing bacteria. Methods The BLAST search of the genes involved in ectoine degradation in the halotolerant methanotroph Methylotuvimicrobium alcaliphilum 20Z was performed with the reference sequences of Halomonas elongata. The genes for the key enzymes of the pathway were disrupted by insertion mutagenesis and the cellular metabolites in the methanol extracts of mutant cells were analyzed by HPLC. The doeA gene from Mm. alcaliphilum 20Z was heterologously expressed in Escherichia coli to identify the product of ectoine hydrolysis catalyzed by ectoine hydrolase DoeA. Results We have shown that the halotolerant methanotroph Mm. alcaliphilum 20Z possesses the doeBDAC gene cluster coding for putative ectoine hydrolase (DoeA), Nα-acetyl-L-2,4-diaminobutyrate deacetylase (DoeB), diaminobutyrate transaminase (DoeD) and aspartate-semialdehyde dehydrogenase (DoeC). The deletion of the doeA gene resulted in accumulation of the higher level of ectoine compared to the wild type strain. Nγ-acetyl-L-2,4-diaminobutyrate (Nγ-acetyl-DAB), a substrate for ectoine synthase, was found in the cytoplasm of the wild type strain. Nα-acetyl-L-2,4-diaminobutyrate (Nα-acetyl-DAB), a substrate for the DoeB enzyme, appeared in the cells as a result of exposure of the doeB mutant to low osmotic pressure. The genes for the enzymes involved in ectoine degradation were found in all aerobic methylotrophs capable of ectoine biosynthesis. These results provide the first evidence for the in vivo operation of the ectoine degradation pathway in methanotrophs and thus expand our understanding of the regulation mechanisms of bacterial osmoadaptation. Conclusions During adaptation to the changes in external osmolarity, halophilic and halotolerant methylotrophs cleave ectoine, thereby entering the carbon and nitrogen of the compatible solute to the central metabolic pathways. The biochemical route of ectoine degradation in the halotolerant methanotroph Mm. alcaliphilum 20Z is similar to that in heterotrophic halophiles. We have shown that ectoine hydrolase DoeA in this methanotroph hydrolyzes ectoine with the formation of the only isomer: Nα-acetyl-DAB. All aerobic methylotrophs capable of ectoine biosynthesis harbor the genetic determinants for ectoine degradation.
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Affiliation(s)
- Aleksander S. Reshetnikov
- Federal Research Center «Pushchino Scientific Center for Biological Research of the Russian Academy of Sciences», G.K. Skryabin Institute of Biochemistry and Physiology of Microorganisms of the Russian Academy of Sciences, Pushchino, Russian Federation
| | - Olga N. Rozova
- Federal Research Center «Pushchino Scientific Center for Biological Research of the Russian Academy of Sciences», G.K. Skryabin Institute of Biochemistry and Physiology of Microorganisms of the Russian Academy of Sciences, Pushchino, Russian Federation
| | - Yuri A. Trotsenko
- Federal Research Center «Pushchino Scientific Center for Biological Research of the Russian Academy of Sciences», G.K. Skryabin Institute of Biochemistry and Physiology of Microorganisms of the Russian Academy of Sciences, Pushchino, Russian Federation
| | - Sergey Yu. But
- Federal Research Center «Pushchino Scientific Center for Biological Research of the Russian Academy of Sciences», G.K. Skryabin Institute of Biochemistry and Physiology of Microorganisms of the Russian Academy of Sciences, Pushchino, Russian Federation
| | - Valentina N. Khmelenina
- Federal Research Center «Pushchino Scientific Center for Biological Research of the Russian Academy of Sciences», G.K. Skryabin Institute of Biochemistry and Physiology of Microorganisms of the Russian Academy of Sciences, Pushchino, Russian Federation
- * E-mail:
| | - Ildar I. Mustakhimov
- Federal Research Center «Pushchino Scientific Center for Biological Research of the Russian Academy of Sciences», G.K. Skryabin Institute of Biochemistry and Physiology of Microorganisms of the Russian Academy of Sciences, Pushchino, Russian Federation
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Govarthanan M, Khalifa AY, Kamala-Kannan S, Srinivasan P, Selvankumar T, Selvam K, Kim W. Significance of allochthonous brackish water Halomonas sp. on biodegradation of low and high molecular weight polycyclic aromatic hydrocarbons. Chemosphere 2020; 243:125389. [PMID: 31765893 DOI: 10.1016/j.chemosphere.2019.125389] [Citation(s) in RCA: 35] [Impact Index Per Article: 8.8] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 10/22/2019] [Revised: 11/11/2019] [Accepted: 11/14/2019] [Indexed: 06/10/2023]
Abstract
The present study is aimed to isolate and identify polycyclic aromatic hydrocarbons (PAHs) degrading bacteria from brackish water and to assess the biodegradation efficiency against low and high molecular weight PAHs. Among 15 isolates, the isolate designated as RM effectively degraded 100 mg/L of phenanthrene (Phe) (67.0%), pyrene (Pyr) (63.0%), naphthalene (NaP) (60.0%), and benzo [a]pyrene (BaP) (58.0%) after 7 days of incubation. Carbon sources, pH, and salinity of the culture medium were optimized to enhance the growth and PAHs biodegradation of the isolate RM. Sucrose was found to be an excellent carbon source to enhance PAHs biodegradation (Phe, 75.0; Pyr, 68.5; NaP, 62.5; and BaP, 59.5%). Furthermore, the isolate showed enhanced degradation at pH 7.0 and 4% salinity. The isolate RM was identified as Halomonas sp. based on partial 16S rDNA gene sequence analysis. The results indicated that the isolate RM (i.e., Halomonas sp.) has the potential to be used in remediation of oil spills in the marine ecosystem.
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Affiliation(s)
- M Govarthanan
- Department of Environmental Engineering, Kyungpook National University, Daegu, 41566, Republic of Korea.
| | - Ashraf Yz Khalifa
- Biological Sciences Department, College of Science, King Faisal University, Saudi Arabia; Botany and Microbiology Department, Faculty of Science, University of Beni-Suef, Beni-Suef, Egypt
| | - S Kamala-Kannan
- Division of Biotechnology, College of Environmental and Bioresource Sciences, Chonbuk National University, Iksan, 54596, Republic of Korea
| | - P Srinivasan
- PG& Research Department of Biotechnology, Mahendra Arts and Science College (Autonomous), Kalippatti, Namakkal, 637501, Tamil Nadu, India
| | - T Selvankumar
- PG& Research Department of Biotechnology, Mahendra Arts and Science College (Autonomous), Kalippatti, Namakkal, 637501, Tamil Nadu, India
| | - K Selvam
- PG& Research Department of Biotechnology, Mahendra Arts and Science College (Autonomous), Kalippatti, Namakkal, 637501, Tamil Nadu, India
| | - Woong Kim
- Department of Environmental Engineering, Kyungpook National University, Daegu, 41566, Republic of Korea.
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Wang C, Huang Y, Zhang Z, Hao H, Wang H. Absence of the nahG-like gene caused the syntrophic interaction between Marinobacter and other microbes in PAH-degrading process. J Hazard Mater 2020; 384:121387. [PMID: 31648897 DOI: 10.1016/j.jhazmat.2019.121387] [Citation(s) in RCA: 27] [Impact Index Per Article: 6.8] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 08/26/2019] [Revised: 09/26/2019] [Accepted: 10/02/2019] [Indexed: 06/10/2023]
Abstract
In this study, Marinobacter sp. N4 isolated from the halophilic consortium CY-1 was found to degrade phenanthrene as a sole carbon source with the accumulation of 1-Hydroxy-2-naphthoic acid (1H2N). With the assistance of Halomonas sp. G29, phenanthrene could be completely mineralized. The hpah1 and hpah2 gene cluster was amplified from the genome of strain N4, that were responsible for upstream and downstream of PAH degradation. Strain N4 was predicted for the transformation from phenanthrene to 1H2N, and strain G29 could transform the produced 1H2N into 1,2-dihydroxynaphthalene (1,2-DHN). The produced 1,2-DHN could be further transformed into salicylic acid (SALA) by strain N4. SALA could be catalyzed into catechol by strain G29 and further utilized by strains N4 and G29 via the catechol 2,3-dioxygenase pathway and catechol 1,2-dioxygenase pathway, respectively. NahG, encoding salicylate hydroxylase, was absent from the hpah2 gene cluster and predicted to be the reason for 1H2N accumulation in the PAH-degrading process by pure culture of strain N4. The syntrophic interaction mode among Marinobacter and other microbes was also predicted. According to our knowledge, this is the first report of the PAH-degrading gene cluster in Marinobacter and the syntrophic interaction between Marinobacter and other microbes in the PAH-degrading process.
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Affiliation(s)
- Chongyang Wang
- State Key Joint Laboratory of Environment Simulation and Pollution Control, School of Environment, Tsinghua University, Beijing, 100084, PR China.
| | - Yong Huang
- State Key Joint Laboratory of Environment Simulation and Pollution Control, School of Environment, Tsinghua University, Beijing, 100084, PR China.
| | - Zuotao Zhang
- State Key Joint Laboratory of Environment Simulation and Pollution Control, School of Environment, Tsinghua University, Beijing, 100084, PR China.
| | - Han Hao
- State Key Joint Laboratory of Environment Simulation and Pollution Control, School of Environment, Tsinghua University, Beijing, 100084, PR China.
| | - Hui Wang
- State Key Joint Laboratory of Environment Simulation and Pollution Control, School of Environment, Tsinghua University, Beijing, 100084, PR China.
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Mostafa YS, Alrumman SA, Otaif KA, Alamri SA, Mostafa MS, Sahlabji T. Production and Characterization of Bioplastic by Polyhydroxybutyrate Accumulating Erythrobacter aquimaris Isolated from Mangrove Rhizosphere. Molecules 2020; 25:E179. [PMID: 31906348 PMCID: PMC6983239 DOI: 10.3390/molecules25010179] [Citation(s) in RCA: 38] [Impact Index Per Article: 9.5] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/29/2019] [Revised: 12/20/2019] [Accepted: 12/31/2019] [Indexed: 01/12/2023] Open
Abstract
The synthesis of bioplastic from marine microbes has a great attendance in the realm of biotechnological applications for sustainable eco-management. This study aims to isolate novel strains of poly-β-hydroxybutyrate (PHB)-producing bacteria from the mangrove rhizosphere, Red Sea, Saudi Arabia, and to characterize the extracted polymer. The efficient marine bacterial isolates were identified by the phylogenetic analysis of the 16S rRNA genes as Tamlana crocina, Bacillus aquimaris, Erythrobacter aquimaris, and Halomonas halophila. The optimization of PHB accumulation by E. aquimaris was achieved at 120 h, pH 8.0, 35 °C, and 2% NaCl, using glucose and peptone as the best carbon and nitrogen sources at a C:N ratio of 9.2:1. The characterization of the extracted biopolymer by Fourier-transform infrared spectroscopy (FTIR), Nuclear magnetic resonance (NMR), and Gas chromatography-mass spectrometry (GC-MS) proves the presence of hydroxyl, methyl, methylene, methine, and ester carbonyl groups, as well as derivative products of butanoic acid, that confirmed the structure of the polymer as PHB. This is the first report on E. aquimaris as a PHB producer, which promoted the hypothesis that marine rhizospheric bacteria were a new area of research for the production of biopolymers of commercial value.
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Affiliation(s)
- Yasser S. Mostafa
- Department of Biology, College of Science, King Khalid University, P.O. Box 9004, Abha 61413, Saudi Arabia; (S.A.A.); (K.A.O.); (S.A.A.)
| | - Sulaiman A. Alrumman
- Department of Biology, College of Science, King Khalid University, P.O. Box 9004, Abha 61413, Saudi Arabia; (S.A.A.); (K.A.O.); (S.A.A.)
| | - Kholod A. Otaif
- Department of Biology, College of Science, King Khalid University, P.O. Box 9004, Abha 61413, Saudi Arabia; (S.A.A.); (K.A.O.); (S.A.A.)
| | - Saad A. Alamri
- Department of Biology, College of Science, King Khalid University, P.O. Box 9004, Abha 61413, Saudi Arabia; (S.A.A.); (K.A.O.); (S.A.A.)
- Prince Sultan Bin Abdulaziz Center for Environmental and Tourism Research and Studies, King Khalid University, P.O. Box 9004, Abha 61413, Saudi Arabia
| | - Mohamed S. Mostafa
- Department of Chemistry, Faculty of Science, Jazan University, P.O. Box 114, Jazan 45142, Saudi Arabia;
| | - Taher Sahlabji
- Department of Chemistry, College of Science, King Khalid University, P.O. Box 9004, Abha 61413, Saudi Arabia;
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Ren J, Wei C, Ma H, Dai M, Fan J, Liu Y, Wu Y, Han R. The Nitrogen-Removal Efficiency of a Novel High-Efficiency Salt-Tolerant Aerobic Denitrifier, Halomonas Alkaliphile HRL-9, Isolated from a Seawater Biofilter. Int J Environ Res Public Health 2019; 16:ijerph16224451. [PMID: 31766146 PMCID: PMC6888400 DOI: 10.3390/ijerph16224451] [Citation(s) in RCA: 9] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 10/17/2019] [Revised: 11/05/2019] [Accepted: 11/07/2019] [Indexed: 11/16/2022]
Abstract
Aerobic denitrification microbes have great potential to solve the problem of NO3--N accumulation in industrialized recirculating aquaculture systems (RASs). A novel salt-tolerant aerobic denitrifier was isolated from a marine recirculating aquaculture system (RAS) and identified as Halomonas alkaliphile HRL-9. Its aerobic denitrification performance in different dissolved oxygen concentrations, temperatures, and C/N ratios was studied. Investigations into nitrogen balance and nitrate reductase genes (napA and narG) were also carried out. The results showed that the optimal conditions for nitrate removal were temperature of 30 °C, a shaking speed of 150 rpm, and a C/N ratio of 10. For nitrate nitrogen (NO3--N) (initial concentration 101.8 mg·L-1), the sole nitrogen source of the growth of HRL-9, the maximum NO3--N removal efficiency reached 98.0% after 24 h and the maximum total nitrogen removal efficiency was 77.3% after 48 h. Nitrogen balance analysis showed that 21.7% of NO3--N was converted into intracellular nitrogen, 3.3% of NO3--N was converted into other nitrification products (i.e., nitrous nitrogen, ammonium nitrogen, and organic nitrogen), and 74.5% of NO3--N might be converted to gaseous products. The identification of functional genes confirmed the existence of the napA gene in strain HRL-9, but no narG gene was found. These results confirm that the aerobic denitrification strain, Halomonas alkaliphile HRL-9, which has excellent aerobic denitrification abilities, can also help us understand the microbiological mechanism and transformation pathway of aerobic denitrification in RASs.
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Affiliation(s)
- Jilong Ren
- School of Marine Technology and Environment, Dalian Ocean University, Dalian 116023, China; (J.R.); (C.W.); (H.M.); (M.D.); (J.F.); (Y.L.)
- Key Laboratory of Environment Controlled Aquaculture, Ministry of Education, Dalian Ocean University, 52 Heishijiao Street, Dalian 116023, China
| | - Chenzheng Wei
- School of Marine Technology and Environment, Dalian Ocean University, Dalian 116023, China; (J.R.); (C.W.); (H.M.); (M.D.); (J.F.); (Y.L.)
- Key Laboratory of Environment Controlled Aquaculture, Ministry of Education, Dalian Ocean University, 52 Heishijiao Street, Dalian 116023, China
| | - Hongjing Ma
- School of Marine Technology and Environment, Dalian Ocean University, Dalian 116023, China; (J.R.); (C.W.); (H.M.); (M.D.); (J.F.); (Y.L.)
- Key Laboratory of Environment Controlled Aquaculture, Ministry of Education, Dalian Ocean University, 52 Heishijiao Street, Dalian 116023, China
| | - Mingyun Dai
- School of Marine Technology and Environment, Dalian Ocean University, Dalian 116023, China; (J.R.); (C.W.); (H.M.); (M.D.); (J.F.); (Y.L.)
- Key Laboratory of Environment Controlled Aquaculture, Ministry of Education, Dalian Ocean University, 52 Heishijiao Street, Dalian 116023, China
| | - Jize Fan
- School of Marine Technology and Environment, Dalian Ocean University, Dalian 116023, China; (J.R.); (C.W.); (H.M.); (M.D.); (J.F.); (Y.L.)
- Key Laboratory of Environment Controlled Aquaculture, Ministry of Education, Dalian Ocean University, 52 Heishijiao Street, Dalian 116023, China
| | - Ying Liu
- School of Marine Technology and Environment, Dalian Ocean University, Dalian 116023, China; (J.R.); (C.W.); (H.M.); (M.D.); (J.F.); (Y.L.)
- Key Laboratory of Environment Controlled Aquaculture, Ministry of Education, Dalian Ocean University, 52 Heishijiao Street, Dalian 116023, China
| | - Yinghai Wu
- College of Marine and Civil Engineering, Dalian Ocean University, Dalian 116023, China;
- South China Institute of Environmental Science, Ministry of Ecology and Environment, Guangzhou 510655, China
| | - Rui Han
- School of Marine Technology and Environment, Dalian Ocean University, Dalian 116023, China; (J.R.); (C.W.); (H.M.); (M.D.); (J.F.); (Y.L.)
- Key Laboratory of Environment Controlled Aquaculture, Ministry of Education, Dalian Ocean University, 52 Heishijiao Street, Dalian 116023, China
- Correspondence:
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Fariq A, Yasmin A, Jamil M. Production, characterization and antimicrobial activities of bio-pigments by Aquisalibacillus elongatus MB592, Salinicoccus sesuvii MB597, and Halomonas aquamarina MB598 isolated from Khewra Salt Range, Pakistan. Extremophiles 2019; 23:435-449. [PMID: 31065815 DOI: 10.1007/s00792-019-01095-7] [Citation(s) in RCA: 28] [Impact Index Per Article: 5.6] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/16/2018] [Accepted: 04/25/2019] [Indexed: 11/27/2022]
Abstract
Hypersaline ecosystems offer unique habitats to microbial populations capable of withstanding extreme stress conditions and producing novel metabolites of commercial importance. Herein, we have characterized for the first time the production of bioactive pigments from newly isolated halophilic bacterial species. Halophilic bacteria were isolated from Khewra Salt Range of Pakistan. Three distinctly colored isolates were selected for pigment production. Selected colonies were identified as Aquisalibacillus elongatus MB592, Salinicoccus sesuvii MB597, and Halomonas aquamarina MB598 based on morphological, biochemical, and physiological evidences as well as 16S rRNA analysis. The optimum pigment production observed at mesophilic condition, nearly neutral pH, and moderate salinity was validated using response surface methodology. Different analytical techniques (UV spectroscopy, infrared spectroscopy, and HPLC) characterized these purified pigments as derivatives of bacterioruberin carotenoids. Antioxidant activity of pigments revealed up to 85% free-radical scavenging activity at the concentration of 30 µg ml-1. Pigments also showed significant antimicrobial activity against Bacillus subtilis, Bacillus pumilus, Enterococcus faecalis, Bacillus cereus, Klebsiella pneumoniae, Alcaligenes faecalis, Pseudomonas geniculata, Enterococcus faecium, Aspergillus fumigatus, Aspergillus flavus, Fusarium solani, and Mucor spp., suggesting potential biomedical applications.
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Affiliation(s)
- Anila Fariq
- Microbiology and Biotechnology Research Lab, Department of Environmental Sciences, Fatima Jinnah Women University, Rawalpindi, 46000, Pakistan
- Department of Biotechnology, Fatima Jinnah Women University, Rawalpindi, 46000, Pakistan
| | - Azra Yasmin
- Microbiology and Biotechnology Research Lab, Department of Environmental Sciences, Fatima Jinnah Women University, Rawalpindi, 46000, Pakistan.
- Department of Biotechnology, Fatima Jinnah Women University, Rawalpindi, 46000, Pakistan.
| | - Muhammad Jamil
- Department of Botany, University of Sargodha, Sargodha, Pakistan
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Potts LD, Perez Calderon LJ, Gubry-Rangin C, Witte U, Anderson JA. Characterisation of microbial communities of drill cuttings piles from offshore oil and gas installations. Mar Pollut Bull 2019; 142:169-177. [PMID: 31232291 DOI: 10.1016/j.marpolbul.2019.03.014] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 11/13/2018] [Revised: 03/03/2019] [Accepted: 03/08/2019] [Indexed: 06/09/2023]
Abstract
Drill cuttings (DC) are produced during hydrocarbon drilling operations and are composed of subsurface rock coated with hydrocarbons and drilling fluids. Historic disposal of DC at sea has resulted in the formation of large piles on the seabed that may be left in situ following infrastructure decommissioning. This study provides a first insight into the microbial abundance, diversity and community structure of two DC piles from North Sea oil and gas installations. The abundance of both bacteria and archaea was lower in DC than in surrounding natural sediments. Microbial diversity and richness within DC were low but increased with distance from the piles. Microbial community structure was significantly different in DC piles compared to nearby natural sediments. DC bacterial communities were dominated by Halomonas, Dietzia and Dethiobacter. The presence of such organisms suggests a potential function of hydrocarbon degradation ability and may play an active role in DC pile remediation.
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Affiliation(s)
- Lloyd D Potts
- School of Biological Sciences, University of Aberdeen, Aberdeen, United Kingdom; Chemical and Materials Engineering, School of Engineering, University of Aberdeen, Aberdeen, United Kingdom.
| | - Luis J Perez Calderon
- School of Biological Sciences, University of Aberdeen, Aberdeen, United Kingdom; Chemical and Materials Engineering, School of Engineering, University of Aberdeen, Aberdeen, United Kingdom
| | - Cecile Gubry-Rangin
- School of Biological Sciences, University of Aberdeen, Aberdeen, United Kingdom
| | - Ursula Witte
- School of Biological Sciences, University of Aberdeen, Aberdeen, United Kingdom
| | - James A Anderson
- Chemical and Materials Engineering, School of Engineering, University of Aberdeen, Aberdeen, United Kingdom
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Romano I, Abbate M, Poli A, D'Orazio L. Bio-cleaning of nitrate salt efflorescence on stone samples using extremophilic bacteria. Sci Rep 2019; 9:1668. [PMID: 30733526 PMCID: PMC6367513 DOI: 10.1038/s41598-018-38187-x] [Citation(s) in RCA: 13] [Impact Index Per Article: 2.6] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/29/2018] [Accepted: 12/21/2018] [Indexed: 11/16/2022] Open
Abstract
For the first time, we propose the use of an extremophilic bacterium to remove nitrate salt efflorescence from the surfaces of stone samples. A haloalkaliphilic bacterium was selected "ad hoc" for its ability to reduce nitrates; i.e. Halomonas campaniensis sp. nov., strain 5AGT (DSM 15293T, ATCC BAA-966T). Quantitative monitoring of nitrate content, on untreated and treated surfaces of stone samples artificially enriched with nitrate, as a function of incubation/treatment time, was carried out by molecular spectroscopy. The results obtained reveal the good performance of Halomonas campaniensis bacterium in decreasing nitrate concentration on stone surfaces both in a controlled laboratory environment for temperature and relative humidity and in a real outdoor environmental conditions.
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Affiliation(s)
- Ida Romano
- Institute of Biomolecular Chemistry of Consiglio Nazionale delle Ricerche, 80078, Pozzuoli, Naples, Italy
| | - Mario Abbate
- Institute for Polymers, Composites and Biomaterials of Consiglio Nazionale delle Ricerche, 80078, Pozzuoli, Naples, Italy
| | - Annarita Poli
- Institute of Biomolecular Chemistry of Consiglio Nazionale delle Ricerche, 80078, Pozzuoli, Naples, Italy
| | - Loredana D'Orazio
- Institute for Polymers, Composites and Biomaterials of Consiglio Nazionale delle Ricerche, 80078, Pozzuoli, Naples, Italy.
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Jiang XR, Yao ZH, Chen GQ. Controlling cell volume for efficient PHB production by Halomonas. Metab Eng 2017; 44:30-37. [PMID: 28918285 DOI: 10.1016/j.ymben.2017.09.004] [Citation(s) in RCA: 58] [Impact Index Per Article: 8.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/28/2017] [Revised: 09/08/2017] [Accepted: 09/11/2017] [Indexed: 01/27/2023]
Abstract
Bacterial morphology is decided by cytoskeleton protein MreB and cell division protein FtsZ encoded by essential genes mreB and ftsZ, respectively. Inactivating mreB and ftsZ lead to increasing cell sizes and cell lengths, respectively, yet seriously reduce cell growth ability. Here we develop a temperature-responsible plasmid expression system for compensated expression of relevant gene(s) in mreB or ftsZ disrupted recombinants H. campaniensis LS21, allowing mreB or ftsZ disrupted recombinants to grow normally at 30°C in a bioreactor for 12h so that a certain cell density can be reached, followed by 36h cell size expansions or cell shape elongations at elevated 37°C at which the mreB and ftsZ encoded plasmid pTKmf failed to replicate in the recombinants and thus lost themselves. Finally, 80% PHB yield increase was achieved via controllable morphology manipulated H. campaniensis LS21. It is concluded that controllable expanding cell volumes (widths or lengths) provides more spaces for accumulating more inclusion body polyhydroxybutyrate (PHB) and the resulting cell gravity precipitation benefits the final separation of cells and product during downstream.
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Affiliation(s)
- Xiao-Ran Jiang
- MOE Key Lab of Bioinformatics, School of Life Sciences, Tsinghua-Peking Center for Life Sciences, Tsinghua University, Beijing 100084, China
| | - Zhi-Hao Yao
- MOE Key Lab of Bioinformatics, School of Life Sciences, Tsinghua-Peking Center for Life Sciences, Tsinghua University, Beijing 100084, China
| | - Guo-Qiang Chen
- MOE Key Lab of Bioinformatics, School of Life Sciences, Tsinghua-Peking Center for Life Sciences, Tsinghua University, Beijing 100084, China; Center for Synthetic and Systems Biology, Tsinghua University, Beijing 100084, China; Center for Nano and Micro Mechanics, Tsinghua University, Beijing 100084, China; MOE Key Laboratory for Industrial Biocatalysis, Tsinghua University, Beijing 100084, China.
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Wang T, Li J, Zhang LH, Yu Y, Zhu YM. Simultaneous heterotrophic nitrification and aerobic denitrification at high concentrations of NaCl and ammonia nitrogen by Halomonas bacteria. Water Sci Technol 2017; 76:386-395. [PMID: 28726704 DOI: 10.2166/wst.2017.214] [Citation(s) in RCA: 12] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/07/2023]
Abstract
To improve the efficiency of simultaneous heterotrophic nitrification and aerobic denitrification (SND) at high concentrations of NaCl and ammonia nitrogen (NH4+-N), we investigated the SND characteristics of Halomonas bacteria with the ability to synthesize the compatible solute ectoine. Halomonas sp. strain B01, which was isolated, screened and identified in this study, could simultaneously remove nitrogen (N) by SND and synthesize ectoine under high NaCl conditions. Gene cloning and sequencing analysis indicated that this bacterial genome contains ammonia monooxygenase (amoA) and nitrate reductase (narH) genes. Optimal conditions for N removal in a solution containing 600 mg/L NH4+-N were as follows: sodium succinate supplied as organic carbon (C) source at a C/N ratio of 5, pH 8 and shaking culture at 90 rpm. The N removal rate was 96.0% under these conditions. The SND by Halomonas sp. strain B01 was performed in N removal medium containing 60 g/L NaCl and 4,000 mg/L NH4+-N; after 180 h the residual total inorganic N concentration was 21.7 mg/L and the N removal rate was 99.2%. Halomonas sp. strain B01, with the ability to synthesize the compatible solute ectoine, could simultaneously tolerate high concentrations of NaCl and NH4+-N and efficiently perform N removal by SND.
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Affiliation(s)
- Te Wang
- Environmental Science and Engineering College, Dalian Maritime University, Dalian 116026, China E-mail:
| | - Jian Li
- Environmental Science and Engineering College, Dalian Maritime University, Dalian 116026, China E-mail:
| | - Ling Hua Zhang
- Environmental Science and Engineering College, Dalian Maritime University, Dalian 116026, China E-mail:
| | - Ying Yu
- Environmental Science and Engineering College, Dalian Maritime University, Dalian 116026, China E-mail:
| | - Yi Min Zhu
- Environmental Science and Engineering College, Dalian Maritime University, Dalian 116026, China E-mail:
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Bharti N, Barnawal D, Maji D, Kalra A. Halotolerant PGPRs Prevent Major Shifts in Indigenous Microbial Community Structure Under Salinity Stress. Microb Ecol 2015; 70:196-208. [PMID: 25542205 DOI: 10.1007/s00248-014-0557-4] [Citation(s) in RCA: 14] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 04/24/2014] [Accepted: 12/09/2014] [Indexed: 05/27/2023]
Abstract
The resilience of soil microbial populations and processes to environmental perturbation is of increasing interest as alteration in rhizosphere microbial community dynamics impacts the combined functions of plant-microbe interactions. The present study was conducted to investigate the effect of inoculation with halotolerant rhizobacteria Bacillus pumilus (STR2), Halomonas desiderata (STR8), and Exiguobacterium oxidotolerans (STR36) on the indigenous root-associated microbial (bacterial and fungal) communities in maize under non-saline and salinity stress. Plants inoculated with halotolerant rhizobacteria recorded improved growth as illustrated by significantly higher shoot and root dry weight and elongation in comparison to un-inoculated control plants under both non-saline and saline conditions. Additive main effect and multiplicative interaction ordination analysis revealed that plant growth promoting rhizobacteria (PGPR) inoculations as well as salinity are major drivers of microbial community shift in maize rhizosphere. Salinity negatively impacts microbial community as analysed through diversity indices; among the PGPR-inoculated plants, STR2-inoculated plants recorded higher values of diversity indices. As observed in the terminal-restriction fragment length polymorphism analysis, the inoculation of halotolerant rhizobacteria prevents major shift of the microbial community structure, thus enhancing the resilience capacity of the microbial communities.
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Affiliation(s)
- Nidhi Bharti
- Microbial Technology Department, CSIR-Central Institute of Medicinal and Aromatic Plants, P.O. CIMAP, Lucknow, 226015, India
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De Vitis V, Guidi B, Contente ML, Granato T, Conti P, Molinari F, Crotti E, Mapelli F, Borin S, Daffonchio D, Romano D. Marine microorganisms as source of stereoselective esterases and ketoreductases: kinetic resolution of a prostaglandin intermediate. Mar Biotechnol (NY) 2015; 17:144-152. [PMID: 25266054 DOI: 10.1007/s10126-014-9602-z] [Citation(s) in RCA: 14] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 05/21/2014] [Accepted: 08/08/2014] [Indexed: 06/03/2023]
Abstract
A screening among bacterial strains isolated from water-brine interface of the deep hypersaline anoxic basins (DHABs) of the Eastern Mediterranean was carried out for the biocatalytical resolution of racemic propyl ester of anti-2-oxotricyclo[2.2.1.0]heptan-7-carboxylic acid (R,S)-1, a key intermediate for the synthesis of D-cloprostenol. Bacillus horneckiae 15A gave highly stereoselective reduction of (R,S)-1, whereas Halomonas aquamarina 9B enantioselectively hydrolysed (R,S)-1; in both cases, enantiomerically pure unreacted (R)-1 could be easily recovered and purified at molar conversion below 57-58%, showing the potential of DHAB extremophile microbiome and marine-derived enzymes in stereoselective biocatalysis.
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Affiliation(s)
- Valerio De Vitis
- Department of Food Environmental and Nutritional Sciences (DEFENS), University of Milan, via Mangiagalli 25, 20133, Milan, Italy
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Okaiyeto K, Nwodo UU, Mabinya LV, Okoh AI. Characterization and Flocculating Properties of a Biopolymer Produced by Halomonas sp. Okoh. Water Environ Res 2015; 87:298-303. [PMID: 26462073 DOI: 10.2175/106143015x14212658613479] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/05/2023]
Abstract
The flocculating efficiency and physiochemical properties of purified bioflocculant produced by Halomonas sp. Okoh were investigated. Approximately 1.213 g/L of bioflocculant was recovered after fermentation under predetermined ambient conditions. Jar test experimentation revealed optimum bioflocculant concentration as 0.2 mg/mL with flocculation activity of 66.1%. The thermostable bioflocculant retained high flocculation activity after heat treatment at 100 °C for 30 minutes; flocculation activity of 74% was achieved. Chemical analysis showed that the bioflocculant was composed of sugar (26.5%), protein (2.64%), and uronic acid (13.3%). The Fourier infrared spectroscopy spectrum of the purified bioflocculant revealed the presence of hydroxyl and carboxylic functional groups. Thermogravimetric analyses showed a varied decomposition step, thus, an indication of varied composition. Scanning electron micrograph revealed the amorphous structure of the bioflocculant. These results suggest potential applicability of the bioflocculant produced by Halomonas sp. Okoh industrially.
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Affiliation(s)
- Kunle Okaiyeto
- Applied and Environmental Microbiology Research Group, Department of Biochemistry and Microbiology, University of Fort Hare, Alice 5700, South Africa
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Biswas J, Ganguly J, Paul AK. Partial characterization of an extracellular polysaccharide produced by the moderately halophilic bacterium Halomonas xianhensis SUR308. Biofouling 2015; 31:735-744. [PMID: 26577604 DOI: 10.1080/08927014.2015.1106479] [Citation(s) in RCA: 11] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/05/2023]
Abstract
A moderately halophilic bacterium, Halomonas xianhensis SUR308 (Genbank Accession No. KJ933394) was isolated from a multi-pond solar saltern at Surala, Ganjam district, Odisha, India. The isolate produced a significant amount (7.87 g l(-1)) of extracellular polysaccharides (EPS) when grown in malt extract-yeast extract medium supplemented with 2.5% NaCl, 0.5% casein hydrolysate and 3% glucose. The EPS was isolated and purified following the conventional method of precipitation and dialysis. Chromatographic analysis (paper, GC and GC-MS) of the hydrolyzed EPS confirmed its heteropolymeric nature and showed that it is composed mainly of glucose (45.74 mol%), galactose (33.67 mol %) and mannose (17.83 mol%). Fourier-transform infrared spectroscopy indicated the presence of methylene and carboxyl groups as characteristic functional groups. In addition, its proton nuclear magnetic resonance spectrum revealed functional groups specific for extracellular polysaccharides. X-ray diffraction analysis revealed the amorphous nature (CIxrd, 0.56) of the EPS. It was thermostable up to 250 °C and displayed pseudoplastic rheology and remarkable stability against pH and salts. These unique properties of the EPS produced by H. xianhensis indicate its potential to act as an agent for detoxification, emulsification and diverse biological activities.
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Affiliation(s)
- Jhuma Biswas
- a Microbiology Laboratory, Department of Botany , University of Calcutta , Kolkata , India
| | - J Ganguly
- b Natural Polysaccharide Laboratory, Department of Chemistry , Indian Institute of Engineering Science and Technology , Shibpur , India
| | - A K Paul
- a Microbiology Laboratory, Department of Botany , University of Calcutta , Kolkata , India
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Chandra P, Singh DP. Removal of Cr (VI) by a halotolerant bacterium Halomonas sp. CSB 5 isolated from sāmbhar salt lake Rajastha (India). Cell Mol Biol (Noisy-le-grand) 2014; 60:64-72. [PMID: 25535715] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/25/2014] [Accepted: 07/29/2014] [Indexed: 06/04/2023]
Abstract
A halotolerant chromate reducing bacterium CSB 5 isolated from the Sambhar Salt Lake (Rajasthan) was identified as Halomonas sp. CSB 5 by 16SrDNA sequence analysis. The isolate could tolerate up to 25% NaCl (w/v) and100 μg mL-1of Chromium hexavalent in the complex medium (CM). Removal of Cr (VI) at concentration of 20, 40 and 60 μg mL-1 was found to be 98%, 90.2%, and 65.7% within a period of 60 hour.Effect of factors like pH and temperature on the total removal of Cr (VI) at 60μg mL-1concentration showed maximum removal at pH 8.0 (77.9 %) and temperature 35°C (82.6%) in 60 hour. The maximum intracellular uptake and surface adsorption (3.22 ± 0.09 and 14.16 ± 0.49 μg mg-1 dry wt.) in CMB 5 bacterium was observed at 75 μg mL-1 of Cr (VI) concentration in 45 min.The results showed that contribution of surface binding was about 4-5 fold higher than the intracellular uptake. Bacterium showed concentration dependent increase in the chromate reductase activity with saturating rate at 60 μg mL-1 concentration of chromium. The values of Km and Vmax with NADH of the bacterium was found to be 0.818 μg mL-1 and 0.085 μg mL-1.min-1.mg-1 protein, respectively. Fourier Transform Infrared Spectroscopy (FTIR) analysis of Cr (VI) binding on membrane surface showed changes in wavenumber between 3300-2800 cm-1due to involvement of proteins and fatty acids in the binding of Cr (VI). The absorption peaks at wavenumbers 1654.9, 1580.3 cm-1, 1248 and 1085.6 cm-1 shifted to lower frequencies due to interaction of Cr (VI) with functional groups like amides and phosphodiester. These results suggested that the isolated CSB 5 bacterium can be used as potential bioremediating agent for removal of Cr (VI) in salt loaded waste water.
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Affiliation(s)
- P Chandra
- Babasaheb Bhimrao Ambedkar University Department of Environmental Science Lucknow India
| | - D P Singh
- Babasaheb Bhimrao Ambedkar University Department of Environmental Science Lucknow India dpsingh_lko@yahoo.com
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Kulkarni SO, Kanekar PP, Jog JP, Sarnaik SS, Nilegaonkar SS. Production of copolymer, poly (hydroxybutyrate-co-hydroxyvalerate) by Halomonas campisalis MCM B-1027 using agro-wastes. Int J Biol Macromol 2014; 72:784-9. [PMID: 25277119 DOI: 10.1016/j.ijbiomac.2014.09.028] [Citation(s) in RCA: 37] [Impact Index Per Article: 3.7] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/19/2014] [Revised: 09/07/2014] [Accepted: 09/22/2014] [Indexed: 11/15/2022]
Abstract
For cost effective production of PHA, agro-wastes like fruit peels, bagasse and deoiled cakes were screened as a sole source of carbon. Halomonas campisalis MCM B-1027, which was isolated from one of the extreme environment, i.e. Lonar Lake, India, was explored for the production of PHA using fruit peels and bagasse having fermentable sugars. Among the agro-wastes tested, 1% (v/v) aqueous extract of bagasse was found to be the optimum carbon source with 47% PHA production on dry cell weight basis. Significant amount of total sugars are utilized and converted into cell mass and PHA, e.g. 62% sugar utilized from bagasse extract, 84% from orange peel extract and 71% from banana peel extract as compared to 51% in case of maltose. Hence the cost of production would be positively reduced. The detailed characterization of PHA formed by H. campisalis using bagasse extract as sole carbon source revealed that the organism produces a copolymer of PHB-co-PHV (94.4:5.6) having molecular weight M(w) 1.394 × 10(6) and melting temperature 168.9 °C. Production of PHA by H. campisalis using aqueous extract of fruit peels and a copolymer PHB-co-PHV using aqueous extract of bagasse is presumably the first report.
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Affiliation(s)
- S O Kulkarni
- Microbial Sciences Division, MACS-Agharkar Research Institute, G.G. Agarkar Road, Pune 411004, India.
| | - P P Kanekar
- Microbial Sciences Division, MACS-Agharkar Research Institute, G.G. Agarkar Road, Pune 411004, India
| | - J P Jog
- Microbial Sciences Division, MACS-Agharkar Research Institute, G.G. Agarkar Road, Pune 411004, India
| | - S S Sarnaik
- Microbial Sciences Division, MACS-Agharkar Research Institute, G.G. Agarkar Road, Pune 411004, India
| | - S S Nilegaonkar
- Microbial Sciences Division, MACS-Agharkar Research Institute, G.G. Agarkar Road, Pune 411004, India
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Desale P, Patel B, Singh S, Malhotra A, Nawani N. Plant growth promoting properties of Halobacillus sp. and Halomonas sp. in presence of salinity and heavy metals. J Basic Microbiol 2014. [PMID: 23775888 DOI: 10.1002/jobm.20120077] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 05/13/2023]
Abstract
Salinity and heavy metal stress are challenging problems in agriculture. Here we report the plant growth promoting ability of three moderate halophiles, Halobacillus sp. ADN1, Halomonas sp. MAN5, and Halobacillus sp. MAN6, in presence of both salinity and heavy metal stress. Halobacillus sp. ADN1, Halomonas sp. MAN5, and Halobacillus sp. MAN6 can tolerate 25, 21, and 29% NaCl, respectively and grow in presence of 1 mM cobalt, cadmium, and nickel and 0.04 mM mercury and 0.03 mM silver. Halobacillus sp. ADN1, Halomonas sp. MAN5, and Halobacillus sp. MAN6 produced 152.5, 95.3, and 167.3 µg/ml indole acetic acid (IAA) and could solubilize 61, 53, and 75 parts per million (ppm) phosphate, respectively in the presence of 15% NaCl. The production of IAA and solubilization of phosphate was well retained in the presence of salinity and heavy metals like 1 mM cadmium, 0.7 mM nickel, 0.04 mM mercury, and 0.03 mM silver. Besides, the strains showed amylase and protease activities and could produce hydrogen cyanide and ammonia in presence of salinity and heavy metals. A mixture of three strains enhanced the root growth of Sesuvium portulacastrum under saline and heavy metal stress, where the root length increased nearly 4.5 ± 0.6 times and root dry weight increased 5.4 ± 0.5 times as compared to control. These strains can thus be useful in microbial assisted phytoremediation of polluted saline soils.
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Affiliation(s)
- Prithviraj Desale
- Dr. D. Y. Patil Biotechnology and Bioinformatics Institute, Dr. D. Y. Patil Vidyapeeth, Pune, 411033, India
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Meng L, Hong S, Liu H, Huang H, Sun H, Xu T, Jiang J. Cloning and identification of Group 1 mrp operon encoding a novel monovalent cation/proton antiporter system from the moderate halophile Halomonas zhaodongensis. Extremophiles 2014; 18:963-72. [PMID: 24996797 DOI: 10.1007/s00792-014-0666-5] [Citation(s) in RCA: 12] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/10/2014] [Accepted: 06/05/2014] [Indexed: 11/26/2022]
Abstract
The novel species Halomonas zhaodongensis NEAU-ST10-25(T) recently identified by our group is a moderate halophile which can grow at the range of 0-2.5 M NaCl (optimum 0.5 M) and pH 6-12 (optimum pH 9). To explore its halo-alkaline tolerant mechanism, genomic DNA was screened from NEAU-ST10-25(T) in this study for Na(+)(Li(+))/H(+) antiporter genes by selection in Escherichia coli KNabc lacking three major Na(+)(Li(+))/H(+) antiporters. One mrp operon could confer tolerance of E. coli KNabc to 0.8 M NaCl and 100 mM LiCl, and an alkaline pH. This operon was previously mainly designated mrp (also mnh, pha or sha) due to its multiple resistance and pH-related activity. Here, we will also use mrp to designate the homolog from H. zhaodongensis (Hz_mrp). Sequence analysis and protein alignment showed that Hz_mrp should belong to Group 1 mrp operons. Further phylogenetic analysis reveals that Hz_Mrp system should represent a novel sub-class of Group 1 Mrp systems. This was confirmed by a significant difference in pH-dependent activity profile or the specificity and affinity for the transported monovalent cations between Hz_Mrp system and all the known Mrp systems. Therefore, we propose that Hz_Mrp should be categorized as a novel Group 1 Mrp system.
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Affiliation(s)
- Lin Meng
- Department of Microbiology and Biotechnology, College of Life Sciences, Northeast Agricultural University, Harbin, 150030, People's Republic of China
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Kawata Y, Ando H, Matsushita I, Tsubota J. Efficient secretion of (R)-3-hydroxybutyric acid from Halomonas sp. KM-1 by nitrate fed-batch cultivation with glucose under microaerobic conditions. Bioresour Technol 2014; 156:400-403. [PMID: 24503050 DOI: 10.1016/j.biortech.2014.01.073] [Citation(s) in RCA: 13] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 12/23/2013] [Accepted: 01/19/2014] [Indexed: 06/03/2023]
Abstract
To establish a sustainable society, commodity chemicals need to be developed from biomass resources. Recently, (R)-3-hydroxybutyric acid ((R)-3-HB), a monomer of bioplastic poly-(R)-3-hydroxybutyric acid (PHB), has attracted attention for its possible use in the chemical industry. Halophilic bacteria have been considered for bioprocess applications due to certain characteristics such as the ability to grow in media containing high levels of the starting carbon source and the ability to be rarely contaminated. A halophilic bacterium Halomonas sp. KM-1 stores PHB intracellularly under aerobic conditions and secretes (R)-3-HB under microaerobic conditions. In this study, we optimized culture conditions to maximize (R)-3-HB secretion by KM-1 cells. By a simple nitrate fed-batch cultivation, Halomonas sp. KM-1 secreted 40.3g/L (R)-3-HB with a productivity of 0.48g L(-1)h(-1) with 20% (w/v) glucose. This level is one of the highest recorded productivity of (R)-3-HB to date.
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Affiliation(s)
- Yoshikazu Kawata
- Health Research Institute, National Institute of Advanced Industrial Science and Technology (AIST), 1-8-31 Midorigaoka, Ikeda, Osaka 563-8577, Japan.
| | - Hitoshi Ando
- Health Research Institute, National Institute of Advanced Industrial Science and Technology (AIST), 1-8-31 Midorigaoka, Ikeda, Osaka 563-8577, Japan
| | - Isao Matsushita
- Energy Technology Laboratories, OSAKA GAS CO., LTD., 6-19-9 Torishima, Konohana-ku, Osaka 554-0051, Japan
| | - Jun Tsubota
- Energy Technology Laboratories, OSAKA GAS CO., LTD., 6-19-9 Torishima, Konohana-ku, Osaka 554-0051, Japan
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Alquier M, Kassim C, Bertron A, Sablayrolles C, Rafrafi Y, Albrecht A, Erable B. Halomonas desiderata as a bacterial model to predict the possible biological nitrate reduction in concrete cells of nuclear waste disposals. J Environ Manage 2014; 132:32-41. [PMID: 24275342 DOI: 10.1016/j.jenvman.2013.10.013] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 07/01/2013] [Revised: 10/11/2013] [Accepted: 10/14/2013] [Indexed: 06/02/2023]
Abstract
After closure of a waste disposal cell in a repository for radioactive waste, resaturation is likely to cause the release of soluble species contained in cement and bituminous matrices, such as ionic species (nitrates, sulfates, calcium and alkaline ions, etc.), organic matter (mainly organic acids), or gases (from steel containers and reinforced concrete structures as well as from radiolysis within the waste packages). However, in the presence of nitrates in the near-field of waste, the waste cell can initiate oxidative conditions leading to enhanced mobility of redox-sensitive radionuclides (RN). In biotic conditions and in the presence of organic matter and/or hydrogen as electron donors, nitrates may be microbiologically reduced, allowing a return to reducing conditions that promote the safety of storage. Our work aims to analyze the possible microbial reactivity of nitrates at the bitumen - concrete interface in conditions as close as possible to radioactive waste storage conditions in order (i) to evaluate the nitrate reaction kinetics; (ii) to identify the by-products (NO2(-), NH4(+), N2, N2O, etc.); and (iii) to discriminate between the roles of planktonic bacteria and those adhering as a biofilm structure in the denitrifying activity. Leaching experiments on solid matrices (bitumen and cement pastes) were first implemented to define the physicochemical conditions that microorganisms are likely to meet at the bitumen-concrete interface, e.g. highly alkaline pH conditions (10 < pH < 11) imposed by the cement matrix. The screening of a range of anaerobic denitrifying bacterial strains led us to select Halomonas desiderata as a model bacterium capable of catalyzing the reaction of nitrate reduction in these particular conditions of pH. The denitrifying activity of H. desiderata was quantified in a batch bioreactor in the presence of solid matrices and/or leachate from bitumen and cement matrices. Denitrification was relatively fast in the presence of cement matrix (<100 h) and 2-3 times slower in the presence of bituminous matrix (pH 9.7). The maximal rate of denitrification was approximately 0.063 mM h(-1) and some traces of nitrite were detected for a few hours (<2%). Overall, the presence of solid cement promoted the kinetics of denitrification. The inspection of the solid surfaces at the end of the experiment revealed the presence of a biofilm of H. desiderata on the cement paste surface. These attached bacteria showed a comparable denitrifying activity to planktonic bacterial culture. However, no colonization of bitumen was observed either by SEM or by epifluorescence microscopy.
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Affiliation(s)
- Marjorie Alquier
- Laboratoire de Génie Chimique, Univ. de Toulouse, INPT, UPS, CNRS, 4, allée Emile Monso, F-31030 Toulouse, France
| | - Caroline Kassim
- Laboratoire de Génie Chimique, Univ. de Toulouse, INPT, UPS, CNRS, 4, allée Emile Monso, F-31030 Toulouse, France
| | - Alexandra Bertron
- Laboratoire Matériaux et Durabilité des Constructions, Univ. de Toulouse, UPS, INSA, 135, avenue de Rangueil, F-31 077 Toulouse Cedex 04, France
| | - Caroline Sablayrolles
- Laboratoire de Chimie Agro-Industrielle, Univ. de Toulouse, INPT, INRA, 4 allée Emile Monso, BP 44 362, 31432 Toulouse Cedex 4, France
| | - Yan Rafrafi
- Laboratoire de Génie Chimique, Univ. de Toulouse, INPT, UPS, CNRS, 4, allée Emile Monso, F-31030 Toulouse, France
| | - Achim Albrecht
- Andra, 1-7, rue Jean-Monnet, 92298 Châtenay-Malabry, France
| | - Benjamin Erable
- Laboratoire de Génie Chimique, Univ. de Toulouse, INPT, UPS, CNRS, 4, allée Emile Monso, F-31030 Toulouse, France.
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49
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Zhang H, Wang Z, Wang L, Mu R, Zou Z, Yuan K, Wang Y, Wu H, Jiang J, Yang L. Cloning and identification of a novel NhaD-type Na+/H+ antiporter from metagenomic DNA of the halophilic bacteria in soil samples around Daban Salt Lake. Extremophiles 2013; 18:89-98. [PMID: 24297704 DOI: 10.1007/s00792-013-0600-2] [Citation(s) in RCA: 10] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/06/2013] [Accepted: 11/14/2013] [Indexed: 11/25/2022]
Abstract
In this study, metagenomic DNA was screened for the Na(+)/H(+) antiporter gene from the halophilic bacteria in Daban Salt Lake by selection in Escherichia coli KNabc lacking three major Na(+)/H(+) antiporters. One gene designated as Hb_nhaD encoding a novel NhaD-type Na(+)/H(+) antiporter was finally cloned. The presence of Hb_NhaD conferred tolerance of E. coli KNabc to up to 0.5 M NaCl and 0.2 M LiCl, and an alkaline pH. Hb_NhaD has the highest identity (70.6%) with a putative NhaD-type Na(+)/H(+) antiporter from an uncharacterized Clostridiaceae species, and also has lower identity with known NhaD-type Na(+)/H(+) antiporters from Halomonas elongata (20.8%), Alkalimonas amylolytica (19.0%), Vibrio parahaemolyticus (18.9%) and Vibrio cholerae (18.7 %). pH-dependent Na(+)(Li(+))/H(+) antiport activity was detected from everted membrane vesicles prepared from E. coli KNabc carrying Hb_nhaD. Hb_NhaD exhibited very high Na(+)(Li(+))/H(+) antiport activity over a wide pH range from 6.5 to 9.0 with the highest activity at pH 7.0 which is significantly different from those of the above known NhaD-type Na(+)/H(+) antiporters. Also, the apparent K m values of Hb_NhaD for Na(+) and Li(+) at pH 7.0 were determined to be 1.31 and 2.16, respectively. Based on the above results, we proposed that Hb_NhaD should be categorized as a novel NhaD-type Na(+)/H(+) antiporter.
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Affiliation(s)
- Hua Zhang
- Rubber Research Institute, Chinese Academy of Tropical Agricultural Sciences, and Key Laboratory of Rubber Biology and Genetic Resource Utilization, Ministry of Agriculture, Hainan, 571737, Hainan, People's Republic of China
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50
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Okaiyeto K, Nwodo UU, Mabinya LV, Okoh AI. Characterization of a bioflocculant produced by a consortium of Halomonas sp. Okoh and Micrococcus sp. Leo. Int J Environ Res Public Health 2013; 10:5097-110. [PMID: 24135818 PMCID: PMC3823338 DOI: 10.3390/ijerph10105097] [Citation(s) in RCA: 50] [Impact Index Per Article: 4.5] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 08/02/2013] [Revised: 09/25/2013] [Accepted: 10/01/2013] [Indexed: 11/16/2022]
Abstract
The physicochemical and flocculating properties of a bioflocculant produced by a bacterial consortium composed of Halomonas sp. Okoh and Micrococcus sp. Leo were investigated. The purified bioflocculant was cation and pH dependent, and optimally flocculated kaolin clay suspension at a dosage of 0.1 mg/mL. The flocculating activity of the bioflocculant was stimulated in the presence of Ca2+, Mn2+, Al3+ and had a wide pH range of 2–10, with the highest flocculating activity of 86% at pH 8. The bioflocculant was thermostable and retained more than 70% of its flocculating activity after being heated at 80 °C for 30 min. Thermogravimetric analyses revealed a partial thermal decomposition of the biofloculant at 400 °C. The infrared spectrum showed the presence of hydroxyl, carboxyl and amino moieties as functional groups. The bioflocculant produced by the bacterial consortium appears to hold promising alternative to inorganic and synthetic organic flocculants that are widely used in wastewater treatment.
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Affiliation(s)
- Kunle Okaiyeto
- Applied and Environmental Microbiology Research Group (AEMREG), Department of Biochemistry and Microbiology, University of Fort Hare, Alice 5700, South Africa.
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