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Cai Y, Chen X, Qi H, Bu F, Shaaban M, Peng QA. Genome analysis of Shewanella putrefaciens 4H revealing the potential mechanisms for the chromium remediation. BMC Genomics 2024; 25:136. [PMID: 38308218 PMCID: PMC10837877 DOI: 10.1186/s12864-024-10031-9] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/04/2023] [Accepted: 01/19/2024] [Indexed: 02/04/2024] Open
Abstract
Microbial remediation of heavy metal polluted environment is ecofriendly and cost effective. Therefore, in the present study, Shewanella putrefaciens stain 4H was previously isolated by our group from the activated sludge of secondary sedimentation tank in a dyeing wastewater treatment plant. The bacterium was able to reduce chromate effectively. The strains showed significant ability to reduce Cr(VI) in the pH range of 8.0 to 10.0 (optimum pH 9.0) and 25-42 ℃ (optimum 30 ℃) and were able to reduce 300 mg/L of Cr(VI) in 72 h under parthenogenetic anaerobic conditions. In this paper, the complete genome sequence was obtained by Nanopore sequencing technology and analyzed chromium metabolism-related genes by comparative genomics The genomic sequence of S. putrefaciens 4H has a length of 4,631,110 bp with a G + C content of 44.66% and contains 4015 protein-coding genes and 3223, 2414, 2343 genes were correspondingly annotated into the COG, KEGG, and GO databases. The qRT-PCR analysis showed that the expression of chrA, mtrC, and undA genes was up-regulated under Cr(VI) stress. This study explores the Chromium Metabolism-Related Genes of S. putrefaciens 4H and will help to deepen our understanding of the mechanisms of Cr(VI) tolerance and reduction in this strain, thus contributing to the better application of S. putrefaciens 4H in the field of remediation of chromium-contaminated environments.
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Affiliation(s)
- Yajun Cai
- College of Environmental Engineering, Wuhan Textile University, Wuhan, 430200, China
- Clean Production of Textile Printing and Dyeing Engineering Research Center of Ministry of Education, Wuhan, 430200, China
| | - Xu Chen
- College of Environmental Engineering, Wuhan Textile University, Wuhan, 430200, China
| | - Hanghang Qi
- College of Environmental Engineering, Wuhan Textile University, Wuhan, 430200, China
| | - Fantong Bu
- College of Environmental Engineering, Wuhan Textile University, Wuhan, 430200, China
| | - Muhammad Shaaban
- College of Agriculture, Henan University of Science and Technology, Luoyang, China
| | - Qi-An Peng
- College of Environmental Engineering, Wuhan Textile University, Wuhan, 430200, China.
- Clean Production of Textile Printing and Dyeing Engineering Research Center of Ministry of Education, Wuhan, 430200, China.
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2
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Huang Y, Tang J, Zhang B, Long ZE, Ni H, Fu X, Zou L. Influencing factors and mechanism of Cr(VI) reduction by facultative anaerobic Exiguobacterium sp. PY14. Front Microbiol 2023; 14:1242410. [PMID: 37637125 PMCID: PMC10449125 DOI: 10.3389/fmicb.2023.1242410] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/19/2023] [Accepted: 07/21/2023] [Indexed: 08/29/2023] Open
Abstract
Microbial reduction is an effective way to deal with hexavalent chromium [Cr(VI)] contamination in the environment, which can significantly mitigate the biotoxicity and migration of this pollutant. The present study investigated the influence of environmental factors on aqueous Cr(VI) removal by a newly isolated facultative anaerobic bacterium, Exiguobacterium sp. PY14, and revealed the reduction mechanism. This strain with a minimum inhibitory concentration of 400 mg/L showed the strongest Cr(VI) removal capacity at pH 8.0 because of its basophilic nature, which was obviously depressed by increasing the Cr(VI) initial concentration under both aerobic and anaerobic conditions. In contrast, the removal rate constant for 50 mg/L of Cr(VI) under anaerobic conditions (1.82 × 10-2 h-1) was 3.3 times that under aerobic conditions. The co-existence of Fe(III) and Cu(II) significantly promoted the removal of Cr(VI), while Ag(I), Pb(II), Zn(II), and Cd(II) inhibited it. Electron-shuttling organics such as riboflavin, humic acid, and anthraquinone-2,6-disulfonate promoted the Cr(VI) removal to varying degrees, and the enhancement was more significant under anaerobic conditions. The removal of aqueous Cr(VI) by strain PY14 was demonstrated to be due to cytoplasmic rather than extracellular reduction by analyzing the contributions of different cell components, and the end products existed in the aqueous solution in the form of organo-Cr(III) complexes. Several possible genes involved in Cr(VI) metabolism, including chrR and chrA that encode well-known Chr family proteins responsible for chromate reduction and transport, respectively, were identified in the genome of PY14, which further clarified the Cr(VI) reduction pathway of this strain. The research progress in the influence of crucial environmental factors and biological reduction mechanisms will help promote the potential application of Exiguobacterium sp. PY14 with high adaptability to environmental stress in Cr(VI) removal in the actual environment.
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Affiliation(s)
- Yunhong Huang
- Nanchang Key Laboratory of Microbial Resources Exploitation and Utilization from Poyang Lake Wetland, College of Life Sciences, Jiangxi Normal University, Nanchang, China
| | - Jie Tang
- Nanchang Key Laboratory of Microbial Resources Exploitation and Utilization from Poyang Lake Wetland, College of Life Sciences, Jiangxi Normal University, Nanchang, China
| | - Bei Zhang
- College of Art and Design, Jiangxi Institute of Fashion Technology, Nanchang, China
| | - Zhong-Er Long
- Nanchang Key Laboratory of Microbial Resources Exploitation and Utilization from Poyang Lake Wetland, College of Life Sciences, Jiangxi Normal University, Nanchang, China
| | - Haiyan Ni
- Nanchang Key Laboratory of Microbial Resources Exploitation and Utilization from Poyang Lake Wetland, College of Life Sciences, Jiangxi Normal University, Nanchang, China
| | - Xueqin Fu
- Nanchang Key Laboratory of Microbial Resources Exploitation and Utilization from Poyang Lake Wetland, College of Life Sciences, Jiangxi Normal University, Nanchang, China
| | - Long Zou
- Nanchang Key Laboratory of Microbial Resources Exploitation and Utilization from Poyang Lake Wetland, College of Life Sciences, Jiangxi Normal University, Nanchang, China
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3
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Rahman Z, Thomas L, Chetri SPK, Bodhankar S, Kumar V, Naidu R. A comprehensive review on chromium (Cr) contamination and Cr(VI)-resistant extremophiles in diverse extreme environments. ENVIRONMENTAL SCIENCE AND POLLUTION RESEARCH INTERNATIONAL 2023; 30:59163-59193. [PMID: 37046169 DOI: 10.1007/s11356-023-26624-y] [Citation(s) in RCA: 4] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 11/01/2022] [Accepted: 03/20/2023] [Indexed: 05/10/2023]
Abstract
Chromium (Cr) compounds are usually toxins and exist abundantly in two different forms, Cr(VI) and Cr(III), in nature. Their contamination in any environment is a major problem. Many extreme environments including cold climate, warm climate, acidic environment, basic/alkaline environment, hypersaline environment, radiation, drought, high pressure, and anaerobic conditions have accumulated elevated Cr contamination. These harsh physicochemical conditions associated with Cr(VI) contamination damage biological systems in various ways. However, several unique microorganisms belonging to phylogenetically distant taxa (bacteria, fungi, and microalgae) owing to different and very distinct physiological characteristics can withstand extremities of Cr(VI) in different physicochemical environments. These challenging situations offer great potential and extended proficiencies in extremophiles for environmental and biotechnological applications. On these issues, the present review draws attention to Cr(VI) contamination from diverse extreme environmental regions. The study gives a detailed account on the ecology and biogeography of Cr(VI)-resistant microorganisms in inhospitable environments, and their use for detoxifying Cr(VI) and other applications. The study also focuses on physiological, multi-omics, and genetic engineering approaches of Cr(VI)-resistant extremophiles.
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Affiliation(s)
- Zeeshanur Rahman
- Department of Botany, Zakir Husain Delhi College, University of Delhi, Delhi, India.
| | - Lebin Thomas
- Department of Botany, Hansraj College, University of Delhi, Delhi, India
| | - Siva P K Chetri
- Department of Botany, Dimoria College, Gauhati University, Guwahati, Assam, India
| | - Shrey Bodhankar
- Department of Agriculture Microbiology, School of Agriculture Sciences, Anurag University, Hyderabad, Telangana, India
| | - Vikas Kumar
- Department of Botany, University of Lucknow, Lucknow, Uttar Pradesh, India
| | - Ravi Naidu
- Global Centre for Environmental Remediation, University of Newcastle, Newcastle, Australia
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4
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Gu Y, Chen X, Liu L, Wang S, Yu X, Jia Z, Zhou X. Cr(VI)-bioremediation mechanism of a novel strain Bacillus paramycoides Cr6 with the powerful ability to remove Cr(VI) from contaminated water. JOURNAL OF HAZARDOUS MATERIALS 2023; 455:131519. [PMID: 37207478 DOI: 10.1016/j.jhazmat.2023.131519] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 11/18/2022] [Revised: 03/23/2023] [Accepted: 04/25/2023] [Indexed: 05/21/2023]
Abstract
This research provided an excellent novel hexavalent chromium (Cr(VI))-removal bacterium, Bacillus paramycoides Cr6, and investigated its removal mechanism from the perspective of molecular biology. Cr6 could resist up to 2500 mg/L Cr(VI), and the removal rate of 2000 mg/L Cr(VI) reached 67.3% under the optimal culture conditions of 220 r/min, pH 8 and 31 ℃. When the initial concentration of Cr(VI) was 200 mg/L, Cr6 had a removal rate of 100% within 18 h. The differential transcriptome analysis identified two key structural genes named bcr005 and bcb765 of Cr6, which were upregulated by Cr(VI). Their functions were predicted and further confirmed by bioinformatic analyses and in vitro experiments. bcr005 encodes Cr(VI)-reductase BCR005, and bcb765 encodes Cr(VI)-binding protein BCB765. Real-time fluorescent quantitative PCRs were performed, and the data illustrated a parallel pathway (one is Cr(VI) reduction, and the other is Cr(VI) immobilisation) of Cr6 to remove Cr(VI), which relies on the synergistic expression of the genes bcr005 and bcb765 induced by different concentrations of Cr(VI). In summary, a deeper molecular mechanism of Cr(VI) microorganism removal was elaborated; Bacillus paramycoides Cr6 was an exceptional novel Cr(VI)-removed bacterial resource, while BCR005 and BCB765 were two new-found efficient enzymes that have potential practical applications for sustainable microbial remediation of Cr-contaminated water.
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Affiliation(s)
- Yawen Gu
- Analytical and Testing Center of Hebei Province, Hebei University of Science and Technology, No.26 of Yuxiang street, Shijiazhuang 050018, Hebei Province, China
| | - Xiaoxia Chen
- Analytical and Testing Center of Hebei Province, Hebei University of Science and Technology, No.26 of Yuxiang street, Shijiazhuang 050018, Hebei Province, China
| | - Liqiang Liu
- College of Food Science and Biology, Hebei University of Science and Technology, No.26 of Yuxiang street, Shijiazhuang 050018, Hebei Province, China
| | - Saifei Wang
- Analytical and Testing Center of Hebei Province, Hebei University of Science and Technology, No.26 of Yuxiang street, Shijiazhuang 050018, Hebei Province, China
| | - Xinran Yu
- College of Food Science and Biology, Hebei University of Science and Technology, No.26 of Yuxiang street, Shijiazhuang 050018, Hebei Province, China
| | - Zhenhua Jia
- Biology Institute, Hebei Academy of Sciences, No.46 of Youyi south street, Shijiazhuang 050081, Hebei Province, China
| | - Xiaohui Zhou
- College of Food Science and Biology, Hebei University of Science and Technology, No.26 of Yuxiang street, Shijiazhuang 050018, Hebei Province, China.
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5
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Ramli NN, Othman AR, Kurniawan SB, Abdullah SRS, Hasan HA. Metabolic pathway of Cr(VI) reduction by bacteria: A review. Microbiol Res 2023; 268:127288. [PMID: 36571921 DOI: 10.1016/j.micres.2022.127288] [Citation(s) in RCA: 7] [Impact Index Per Article: 7.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/27/2022] [Revised: 10/26/2022] [Accepted: 12/15/2022] [Indexed: 12/23/2022]
Abstract
Heavy metal wastes, particularly hexavalent chromium [Cr(VI)], are generated from anthropogenic activities, and their increasing abundance has been a research concern due to their toxicity, genotoxicity, carcinogenicity and mutagenicity. Exposure to these dangerous pollutants could lead to chronic infections and even mortality in humans and animals. Bioremediation using microorganisms, particularly bacteria, has gained considerable interest because it can remove contaminants naturally and is safe to the surrounding environment. Bacteria, such as Pseudomonas putida and Bacillus subtilis, can reduce the toxic Cr(VI) to the less toxic trivalent chromium Cr(III) through mechanisms including biotransformation, biosorption and bioaccumulation. These mechanisms are mostly linked to chromium reductase and nitroreductase enzymes, which are involved in the Cr(VI) reduction pathway. However, relevant data on the nitroreductase route remain insufficient. Thus, this work proposes an alternative metabolic pathway of nitroreductase, wherein nitrate activates the reaction and indirectly reduces toxic chromium. This nitroreductase pathway occurs concurrently with the chromium reduction pathway.
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Affiliation(s)
- Nur Nadhirah Ramli
- Department of Chemical and Process Engineering, Faculty of Engineering and Built Environment, Universiti Kebangsaan Malaysia, 43600 UKM Bangi, Selangor, Malaysia.
| | - Ahmad Razi Othman
- Department of Chemical and Process Engineering, Faculty of Engineering and Built Environment, Universiti Kebangsaan Malaysia, 43600 UKM Bangi, Selangor, Malaysia.
| | - Setyo Budi Kurniawan
- Department of Chemical and Process Engineering, Faculty of Engineering and Built Environment, Universiti Kebangsaan Malaysia, 43600 UKM Bangi, Selangor, Malaysia
| | - Siti Rozaimah Sheikh Abdullah
- Department of Chemical and Process Engineering, Faculty of Engineering and Built Environment, Universiti Kebangsaan Malaysia, 43600 UKM Bangi, Selangor, Malaysia
| | - Hassimi Abu Hasan
- Department of Chemical and Process Engineering, Faculty of Engineering and Built Environment, Universiti Kebangsaan Malaysia, 43600 UKM Bangi, Selangor, Malaysia; Research Centre for Sustainable Process Technology (CESPRO), Faculty of Engineering and Built Environment, Universiti Kebangsaan Malaysia, 43600 UKM Bangi, Selangor, Malaysia
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6
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Su YQ, Min SN, Jian XY, Guo YC, He SH, Huang CY, Zhang Z, Yuan S, Chen YE. Bioreduction mechanisms of high-concentration hexavalent chromium using sulfur salts by photosynthetic bacteria. CHEMOSPHERE 2023; 311:136861. [PMID: 36243096 DOI: 10.1016/j.chemosphere.2022.136861] [Citation(s) in RCA: 6] [Impact Index Per Article: 6.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 05/10/2022] [Revised: 08/06/2022] [Accepted: 10/10/2022] [Indexed: 06/16/2023]
Abstract
Eliminating "sulfur starvation" caused by competition for sulfate transporters between chromate and sulfate is crucial to enhance the content of sulfur-containing compounds and improve the tolerance and reduction capability of Cr(VI) in bacteria. In this study, the effects of sulfur salts on the Cr(VI) bioremediation and the possible mechanism were investigated in Rhodobacter sphaeroides SC01 by cell imaging, spectroscopy, and biochemical measurements. The results showed that, when the concentration of metabisulfite was 2.0 g L-1, and the initial OD600 was 0.33, the reduction rate of R. sphaeroides SC01 reached up to 91.3% for 500 mg L-1 Cr(VI) exposure at 96 h. Moreover, thiosulfate and sulfite also markedly increased the concentration of reduced Cr(VI) in R. sphaeroides SC01. Furthermore, the characterization results revealed that -OH, -CONH, -COOH, -SO3, -PO3, and -S-S- played a major role in the adsorption of Cr, and Cr(III) reduced by bacteria was bioprecipitated in the production of Cr2P3S9 and CrPS4. In addition, R. sphaeroids SC01 combined with metabisulfite significantly increased the activity of glutathione peroxidase and the content of glutathione (GSH) and total sulfhydryl while decreasing reactive oxygen species (ROS) accumulation and cell death induced by Cr(VI) toxic. Overall, the results of this research revealed a highly efficient and reliable strategy for Cr(VI) removal by photosynthetic bacteria combined with sulfur salts in high-concentration Cr(VI)-contaminated wastewater.
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Affiliation(s)
- Yan-Qiu Su
- College of Life Science, Sichuan Normal University, Chengdu, China.
| | - Shuang-Nan Min
- College of Life Science, Sichuan Normal University, Chengdu, China
| | - Xin-Yi Jian
- College of Life Science, Sichuan Normal University, Chengdu, China
| | - Yuan-Cheng Guo
- College of Life Science, Sichuan Normal University, Chengdu, China
| | - Shu-Hao He
- College of Life Science, Sichuan Normal University, Chengdu, China
| | - Chun-Yi Huang
- College of Life Science, Sichuan Normal University, Chengdu, China
| | - Zheng Zhang
- College of Life Science, Sichuan Normal University, Chengdu, China
| | - Shu Yuan
- College of Resources, Sichuan Agricultural University, Chengdu, China
| | - Yang-Er Chen
- College of Life Sciences, Sichuan Agricultural University, Ya'an, China.
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7
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Tufail MA, Iltaf J, Zaheer T, Tariq L, Amir MB, Fatima R, Asbat A, Kabeer T, Fahad M, Naeem H, Shoukat U, Noor H, Awais M, Umar W, Ayyub M. Recent advances in bioremediation of heavy metals and persistent organic pollutants: A review. THE SCIENCE OF THE TOTAL ENVIRONMENT 2022; 850:157961. [PMID: 35963399 DOI: 10.1016/j.scitotenv.2022.157961] [Citation(s) in RCA: 25] [Impact Index Per Article: 12.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 05/07/2022] [Revised: 08/02/2022] [Accepted: 08/06/2022] [Indexed: 06/15/2023]
Abstract
Heavy metals and persistent organic pollutants are causing detrimental effects on the environment. The seepage of heavy metals through untreated industrial waste destroys the crops and lands. Moreover, incineration and combustion of several products are responsible for primary and secondary emissions of pollutants. This review has gathered the remediation strategies, current bioremediation technologies, and their primary use in both in situ and ex situ methods, followed by a detailed explanation for bioremediation over other techniques. However, an amalgam of bioremediation techniques and nanotechnology could be a breakthrough in cleaning the environment by degrading heavy metals and persistant organic pollutants.
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Affiliation(s)
| | - Jawaria Iltaf
- Institute of Chemistry, University of Sargodha, 40100, Pakistan
| | - Tahreem Zaheer
- Department of Biological Physics, Eötvös Loránd University, Pázmány Péter sétány 1/A, 1117 Budapest, Hungary
| | - Leeza Tariq
- Centre of Excellence in Molecular Biology, University of the Punjab, Lahore 53700, Pakistan
| | - Muhammad Bilal Amir
- Key Laboratory of Insect Ecology and Molecular Biology, College of Plant Health and Medicine, Qingdao Agricultural University, Qingdao 266109, China
| | - Rida Fatima
- School of Science, Department of Chemistry, University of Management and Technology, Lahore, Pakistan
| | - Ayesha Asbat
- Department of Pharmacy, The University of Lahore, Lahore, Pakistan
| | - Tahira Kabeer
- Center of Agriculture Biochemistry and Biotechnology CABB, University of Agriculture, Faisalabad, Pakistan
| | - Muhammad Fahad
- Department of Plant Breeding and Genetics, Bahauddin Zakariya University, Multan, Pakistan
| | - Hamna Naeem
- Department of Environmental Sciences, Fatima Jinnah Women University, The Mall, 46000 Rawalpindi, Pakistan
| | - Usama Shoukat
- Integrated Genomics Cellular Development Biology Lab, Department of Entomology, University of Agriculture, Faisalabad, Pakistan
| | - Hazrat Noor
- Department of Microbiology, Faculty of Biological Sciences, Quaid-i-Azam University, Islamabad 45320, Pakistan
| | - Muhammad Awais
- International Center for Chemical and Biological Sciences, University of Karachi, Karachi 75270, Pakistan
| | - Wajid Umar
- Institute of Environmental Science, Hungarian University of Agriculture and Life Sciences, Gödöllő 2100, Hungary
| | - Muhaimen Ayyub
- Institute of Soil and Environmental Sciences, University of Agriculture Faisalabad, Pakistan
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Zhou Z, Zhu L, Dong Y, You L, Zheng S, Wang G, Xia X. Identification of a Novel Chromate and Selenite Reductase FesR in Alishewanella sp. WH16-1. Front Microbiol 2022; 13:834293. [PMID: 35350625 PMCID: PMC8957926 DOI: 10.3389/fmicb.2022.834293] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/13/2021] [Accepted: 02/10/2022] [Indexed: 12/04/2022] Open
Abstract
A ferredoxin protein (AAY72_06850, named FesR) was identified to associate with chromate [Cr(VI)] resistance in Alishewanella sp. WH16-1. FesR and its similar proteins were phylogenetically separated from other reductase families. Unlike the reported Cr(VI) and selenite [Se(IV)] reductases, two 4Fe-4S clusters and one flavin adenine dinucleotide (FAD) -binding domain were found in the FesR sequence. The experiment in vivo showed that the mutant strain ΔfesR had lost partial Cr(VI) and Se(IV) reduction capacities compared to the wild-type and complemented strains. Furthermore, overexpression in Escherichia coli and enzymatic tests in vitro showed FesR were involved in Cr(VI) and Se(IV) reduction. 4Fe-4S cluster in purified FesR was detected by ultraviolet-visible spectrum (UV-VIS) and Electron Paramagnetic Resonance (EPR). The Km values of FesR for Cr(VI) and Se(IV) reduction were 1682.0 ± 126.2 and 1164.0 ± 89.4 μmol/L, and the Vmax values for Cr(VI) and Se(IV) reduction were 4.1 ± 0.1 and 9.4 ± 0.3 μmol min–1 mg–1, respectively. Additionally, site-directed mutagenesis and redox potential analyses showed that 4Fe-4S clusters were essential to FesR, and FAD could enhance the enzyme efficiencies of FesR as intracellular electron transporters. To the best of our knowledge, FesR is a novel Cr(VI) and Se(IV) reductase.
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Affiliation(s)
- Zijie Zhou
- State Key Laboratory of Agricultural Microbiology, College of Life Science and Technology, Huazhong Agricultural University, Wuhan, China
| | - Lin Zhu
- State Key Laboratory of Agricultural Microbiology, College of Life Science and Technology, Huazhong Agricultural University, Wuhan, China
| | - Yixuan Dong
- State Key Laboratory of Agricultural Microbiology, College of Life Science and Technology, Huazhong Agricultural University, Wuhan, China
| | - Lexing You
- College of Geography and Environmental Sciences, Zhejiang Normal University, Jinhua, China
| | - Shixue Zheng
- State Key Laboratory of Agricultural Microbiology, College of Life Science and Technology, Huazhong Agricultural University, Wuhan, China
| | - Gejiao Wang
- State Key Laboratory of Agricultural Microbiology, College of Life Science and Technology, Huazhong Agricultural University, Wuhan, China
| | - Xian Xia
- State Key Laboratory of Agricultural Microbiology, College of Life Science and Technology, Huazhong Agricultural University, Wuhan, China.,Hubei Key Laboratory of Edible Wild Plants Conservation & Utilization, Huangshi Key Laboratory of Lake Environmental Protection and Sustainable Utilization of Resources, Hubei Engineering Research Center of Characteristic Wild Vegetable Breeding and Comprehensive Utilization Technology, College of Life Sciences, Hubei Normal University, Huangshi, China
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9
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Glodowska M, Welte CU, Kurth JM. Metabolic potential of anaerobic methane oxidizing archaea for a broad spectrum of electron acceptors. Adv Microb Physiol 2022; 80:157-201. [PMID: 35489791 DOI: 10.1016/bs.ampbs.2022.01.003] [Citation(s) in RCA: 4] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/27/2023]
Abstract
Methane (CH4) is a potent greenhouse gas significantly contributing to the climate warming we are currently facing. Microorganisms play an important role in the global CH4 cycle that is controlled by the balance between anaerobic production via methanogenesis and CH4 removal via methanotrophic oxidation. Research in recent decades advanced our understanding of CH4 oxidation, which until 1976 was believed to be a strictly aerobic process. Anaerobic oxidation of methane (AOM) coupled to sulfate reduction is now known to be an important sink of CH4 in marine ecosystems. Furthermore, in 2006 it was discovered that anaerobic CH4 oxidation can also be coupled to nitrate reduction (N-DAMO), demonstrating that AOM may be much more versatile than previously thought and linked to other electron acceptors. In consequence, an increasing number of studies in recent years showed or suggested that alternative electron acceptors can be used in the AOM process including FeIII, MnIV, AsV, CrVI, SeVI, SbV, VV, and BrV. In addition, humic substances as well as biochar and perchlorate (ClO4-) were suggested to mediate AOM. Anaerobic methanotrophic archaea, the so-called ANME archaea, are key players in the AOM process, yet we are still lacking deeper understanding of their metabolism, electron acceptor preferences and their interaction with other microbial community members. It is still not clear whether ANME archaea can oxidize CH4 and reduce metallic electron acceptors independently or via electron transfer to syntrophic partners, interspecies electron transfer, nanowires or conductive pili. Therefore, the aim of this review is to summarize and discuss the current state of knowledge about ANME archaea, focusing on their physiology, metabolic flexibility and potential to use various electron acceptors.
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Affiliation(s)
- Martyna Glodowska
- Department of Microbiology, Radboud Institute for Biological and Environmental Sciences, Radboud University, Nijmegen, The Netherlands.
| | - Cornelia U Welte
- Department of Microbiology, Radboud Institute for Biological and Environmental Sciences, Radboud University, Nijmegen, The Netherlands.
| | - Julia M Kurth
- Department of Microbiology, Radboud Institute for Biological and Environmental Sciences, Radboud University, Nijmegen, The Netherlands
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10
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Huang Q, Zhang X, Chen Q, Tian S, Tong W, Zhang W, Chen Y, Ma M, Chen B, Wang B, Wang JB. Discovery of a P450-Catalyzed Oxidative Defluorination Mechanism toward Chiral Organofluorines: Uncovering a Hidden Pathway. ACS Catal 2021. [DOI: 10.1021/acscatal.1c05510] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/14/2022]
Affiliation(s)
- Qun Huang
- Key Laboratory of Chemical Biology and Traditional Chinese Medicine Research (Ministry of Education) and Key Laboratory of Phytochemistry R&D of Hunan Province, College of Chemistry and Chemical Engineering, Hunan Normal University, 410081 Changsha, People’s Republic of China
| | - Xuan Zhang
- State Key Laboratory of Physical Chemistry of Solid Surfaces and Fujian Provincial Key Laboratory of Theoretical and Computational Chemistry, College of Chemistry and Chemical Engineering, Xiamen University, 360015 Xiamen, People’s Republic of China
| | - Qianqian Chen
- State Key Laboratory of Physical Chemistry of Solid Surfaces and Fujian Provincial Key Laboratory of Theoretical and Computational Chemistry, College of Chemistry and Chemical Engineering, Xiamen University, 360015 Xiamen, People’s Republic of China
| | - Shaixiao Tian
- Key Laboratory of Chemical Biology and Traditional Chinese Medicine Research (Ministry of Education) and Key Laboratory of Phytochemistry R&D of Hunan Province, College of Chemistry and Chemical Engineering, Hunan Normal University, 410081 Changsha, People’s Republic of China
| | - Wei Tong
- Key Laboratory of Chemical Biology and Traditional Chinese Medicine Research (Ministry of Education) and Key Laboratory of Phytochemistry R&D of Hunan Province, College of Chemistry and Chemical Engineering, Hunan Normal University, 410081 Changsha, People’s Republic of China
| | - Wei Zhang
- Key Laboratory of Chemical Biology and Traditional Chinese Medicine Research (Ministry of Education) and Key Laboratory of Phytochemistry R&D of Hunan Province, College of Chemistry and Chemical Engineering, Hunan Normal University, 410081 Changsha, People’s Republic of China
| | - Yingzhuang Chen
- Key Laboratory of Chemical Biology and Traditional Chinese Medicine Research (Ministry of Education) and Key Laboratory of Phytochemistry R&D of Hunan Province, College of Chemistry and Chemical Engineering, Hunan Normal University, 410081 Changsha, People’s Republic of China
| | - Ming Ma
- Key Laboratory of Chemical Biology and Traditional Chinese Medicine Research (Ministry of Education) and Key Laboratory of Phytochemistry R&D of Hunan Province, College of Chemistry and Chemical Engineering, Hunan Normal University, 410081 Changsha, People’s Republic of China
| | - Bo Chen
- Key Laboratory of Chemical Biology and Traditional Chinese Medicine Research (Ministry of Education) and Key Laboratory of Phytochemistry R&D of Hunan Province, College of Chemistry and Chemical Engineering, Hunan Normal University, 410081 Changsha, People’s Republic of China
| | - Binju Wang
- State Key Laboratory of Physical Chemistry of Solid Surfaces and Fujian Provincial Key Laboratory of Theoretical and Computational Chemistry, College of Chemistry and Chemical Engineering, Xiamen University, 360015 Xiamen, People’s Republic of China
| | - Jian-bo Wang
- Key Laboratory of Chemical Biology and Traditional Chinese Medicine Research (Ministry of Education) and Key Laboratory of Phytochemistry R&D of Hunan Province, College of Chemistry and Chemical Engineering, Hunan Normal University, 410081 Changsha, People’s Republic of China
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11
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Su YQ, Yuan S, Guo YC, Tan YY, Mao HT, Cao Y, Chen YE. Highly efficient and sustainable removal of Cr (VI) in aqueous solutions by photosynthetic bacteria supplemented with phosphor salts. CHEMOSPHERE 2021; 283:131031. [PMID: 34134043 DOI: 10.1016/j.chemosphere.2021.131031] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 11/08/2020] [Revised: 04/06/2021] [Accepted: 05/22/2021] [Indexed: 06/12/2023]
Abstract
Photosynthetic bacteria have flexible metabolisms and strong environmental adaptability, and require cheap, but plentiful, energy supplements, which all enable their use in Cr(VI)-remediation. In this study, the effects of culture conditions on the total Cr removal rate were investigated for a newly identified strain of Rhodobacter sphaeroides SC01. The subcellular distribution and Cr(VI) reduction ability of four different cellular fractions were evaluated by scanning electron microscopy and transmission electron microscopy. Experiments indicated that the optimal culture conditions for total Cr removal included a culture temperature of 35 °C, pH of 7.20, an NaCl concentration of 5 g L-1, a light intensity of 4000 lx, and an initial cell concentration (OD680) of 0.15. In addition, most Cr was found in the cell membrane in the form of Cr (III) after reduction, while cell membranes had the highest Cr(VI) reduction rate (99%) compared to other cellular components. In addition, the physical and chemical properties of SC01 cells were characterized by FTIR, XPS, and XRD analyses, confirming that Cr was successfully absorbed on bacterial cell surfaces. CrPO4‧6H2O and Cr5(P3O10)3 precipitates were particularly identified by XRD analysis. After screening supplementation with five phosphor salts, Cr(VI) reduction due to bioprecipitation was improved by the addition of Na4P2O7 and (NaPO3)6 salts, with the Cr(VI)-reduction rate combined with Na4P2O7 addition being 15% higher than that of the control. Thus, this study proposes a new Cr(VI)-removal strategy based on the combined use of photosynthetic bacteria and phosphor salts, which importantly increases its potential application in treating wastewater.
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Affiliation(s)
- Yan-Qiu Su
- College of Life Science, Sichuan Normal University, Chengdu, China.
| | - Shu Yuan
- College of Life Sciences, Sichuan Agricultural University, Ya'an, China
| | - Yuan-Cheng Guo
- College of Life Science, Sichuan Normal University, Chengdu, China
| | - Yong-Yao Tan
- College of Life Science, Sichuan Normal University, Chengdu, China
| | - Hao-Tian Mao
- College of Life Sciences, Sichuan Agricultural University, Ya'an, China
| | - Yi Cao
- Microbiology and Metabolic Engineering of Key Laboratory of Sichuan Province, College of Life Sciences, Sichuan University, Chengdu, China
| | - Yang-Er Chen
- College of Life Sciences, Sichuan Agricultural University, Ya'an, China.
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12
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Yu Z, Pei Y, Zhao S, Kakade A, Khan A, Sharma M, Zain H, Feng P, Ji J, Zhou T, Wang H, Wu J, Li X. Metatranscriptomic analysis reveals active microbes and genes responded to short-term Cr(VI) stress. ECOTOXICOLOGY (LONDON, ENGLAND) 2021; 30:1527-1537. [PMID: 33123966 DOI: 10.1007/s10646-020-02290-5] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Accepted: 10/10/2020] [Indexed: 06/11/2023]
Abstract
Heavy metals have been severely polluting the environment. However, the response mechanism of microbial communities to short-term heavy metals stress remains unclear. In this study, metagenomics (MG) and metatranscriptomics (MT) was performed to observe the microbial response to short-term Cr(VI) stress. MG data showed that 99.1% of species were similar in the control and Cr(VI) treated groups. However, MT data demonstrated that 83% of the microbes were active in which 58.7% increased, while the relative abundance of 41.3% decreased after short-term Cr(VI) incubation. The MT results also revealed 9% of microbes were dormant in samples. Genes associated with oxidative stress, Cr(VI) transport, resistance, and reduction, as well as genes with unknown functions were 2-10 times upregulated after Cr(VI) treatment. To further confirm the function of unknown genes, two genes (314 and 494) were selected to detect the Cr(VI) resistance and reduction ability. The results showed that these genes significantly increased the Cr(VI) remediation ability of Escherichia coli. MT results also revealed an increase in the expression of some rare genera (at least two times) after Cr(VI) treatment, indicating these rare species played a crucial role in microbial response to short-term Cr(VI) stress. In summary, MT is an efficient way to understand the role of active and dormant microbes in specific environmental conditions.
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Affiliation(s)
- Zhengsheng Yu
- Ministry of Education Key Laboratory of Cell Activities and Stress Adaptations, School of Life Sciences, Lanzhou University, Tianshuinanlu #222, Lanzhou, 730000, Gansu, PR China
- Gansu Key Laboratory of Biomonitoring and Bioremediation for Environment Pollution, School of Life Science, Lanzhou University, Tianshuinanlu #222, Lanzhou, 730000, Gansu, PR China
| | - Yaxin Pei
- Ministry of Education Key Laboratory of Cell Activities and Stress Adaptations, School of Life Sciences, Lanzhou University, Tianshuinanlu #222, Lanzhou, 730000, Gansu, PR China
- Gansu Key Laboratory of Biomonitoring and Bioremediation for Environment Pollution, School of Life Science, Lanzhou University, Tianshuinanlu #222, Lanzhou, 730000, Gansu, PR China
| | - Shuai Zhao
- Gansu Key Laboratory of Biomonitoring and Bioremediation for Environment Pollution, School of Life Science, Lanzhou University, Tianshuinanlu #222, Lanzhou, 730000, Gansu, PR China
| | - Apurva Kakade
- Gansu Key Laboratory of Biomonitoring and Bioremediation for Environment Pollution, School of Life Science, Lanzhou University, Tianshuinanlu #222, Lanzhou, 730000, Gansu, PR China
| | - Aman Khan
- Ministry of Education Key Laboratory of Cell Activities and Stress Adaptations, School of Life Sciences, Lanzhou University, Tianshuinanlu #222, Lanzhou, 730000, Gansu, PR China
| | - Monika Sharma
- Gansu Key Laboratory of Biomonitoring and Bioremediation for Environment Pollution, School of Life Science, Lanzhou University, Tianshuinanlu #222, Lanzhou, 730000, Gansu, PR China
| | - Hajira Zain
- Gansu Key Laboratory of Biomonitoring and Bioremediation for Environment Pollution, School of Life Science, Lanzhou University, Tianshuinanlu #222, Lanzhou, 730000, Gansu, PR China
| | - Pengya Feng
- Gansu Key Laboratory of Biomonitoring and Bioremediation for Environment Pollution, School of Life Science, Lanzhou University, Tianshuinanlu #222, Lanzhou, 730000, Gansu, PR China
| | - Jing Ji
- Ministry of Education Key Laboratory of Cell Activities and Stress Adaptations, School of Life Sciences, Lanzhou University, Tianshuinanlu #222, Lanzhou, 730000, Gansu, PR China
- Gansu Key Laboratory of Biomonitoring and Bioremediation for Environment Pollution, School of Life Science, Lanzhou University, Tianshuinanlu #222, Lanzhou, 730000, Gansu, PR China
| | - Tuoyu Zhou
- Ministry of Education Key Laboratory of Cell Activities and Stress Adaptations, School of Life Sciences, Lanzhou University, Tianshuinanlu #222, Lanzhou, 730000, Gansu, PR China
| | - Haoyang Wang
- McMaster University, 1280 Main Street West, Hamilton, ON, Canada
| | - Jingyuan Wu
- The First Clinical Medical College, Lanzhou University, Tianshuinanlu #222, Lanzhou, 730000, Gansu, PR China
| | - Xiangkai Li
- Ministry of Education Key Laboratory of Cell Activities and Stress Adaptations, School of Life Sciences, Lanzhou University, Tianshuinanlu #222, Lanzhou, 730000, Gansu, PR China.
- Gansu Key Laboratory of Biomonitoring and Bioremediation for Environment Pollution, School of Life Science, Lanzhou University, Tianshuinanlu #222, Lanzhou, 730000, Gansu, PR China.
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13
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Li SW, Wen Y, Leng Y. Transcriptome analysis provides new insights into the tolerance and reduction of Lysinibacillus fusiformis 15-4 to hexavalent chromium. Appl Microbiol Biotechnol 2021; 105:7841-7855. [PMID: 34546405 DOI: 10.1007/s00253-021-11586-3] [Citation(s) in RCA: 6] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/16/2021] [Revised: 08/22/2021] [Accepted: 08/26/2021] [Indexed: 12/13/2022]
Abstract
Microbial bioremediation of Cr(VI)-contaminated environments has drawn extensive concern. However, the molecular processes underlying the microbial Cr(VI) tolerance and reduction remain unclear. We isolated a Cr(VI)-reducing Lysinibacillus fusiformis strain 15-4 from soil on the Qinghai-Tibet Plateau. When grown in 1 mM and 2 mM Cr(VI)-containing medium, strain 15-4 could reduce 100% and 93.7% of Cr(VI) to Cr(III) after 36 h and 60 h of incubation, respectively. To know the molecular processes in response to Cr(VI), transcriptome sequencing was carried out using RNA-Seq technology. The results annotated a total of 3913 expressed genes in the strain. One thousand ninety-eight genes (28.1%) were significantly (fold change ≥ 2, false discovery rate ≤ 0.05) expressed in response to Cr(VI), of which 605 (55.1%) were upregulated and 493 (44.9%) were downregulated. The enrichment analysis showed that a total of 630 differentially expressed genes (DEGs) were enriched to 122 KEGG pathways, of which 8 pathways were significantly (p < 0.05) enriched in Cr(VI)-treated sample, including ATP-binding cassette (ABC) transporters (97 DEGs), ribosome (40), sulfur metabolism (16), aminoacyl-tRNA biosynthesis (19), porphyrin metabolism (20), quorum sensing (44), oxidative phosphorylation (17), and histidine metabolism (10), suggesting that these pathways play key roles to cope with Cr(VI) in the strain. The highly upregulated DEGs consisted of 29 oxidoreductase, 18 dehydrogenase, 14 cell redox homeostasis and stress response protein, and 10 DNA damage and repair protein genes. However, seven Na+:H+ antiporter complex-coding DEGs and most of transcriptional regulator-coding DEGs were significantly downregulated in the Cr-treated sample. Many of FMN/NAD(P)H-dependent reductase-encoding genes were greatly induced by Cr, suggesting the involvement of these genes in Cr(VI) reduction in strain 15-4. Sulfur and iron ions as well as the thiol-disulfide exchange reactions might play synergistic roles in Cr reduction.Key points• Lysinibacillus fusiformis 15-4 was able to tolerate and reduce Cr(VI) to Cr(III).• Transcriptome analysis revealed that 1098 DEGs and 8 key KEGG pathways significantly responded to Cr(VI).• Sulfur metabolism, protein biosynthesis, and porphyrin metabolism were the key pathways associated with the survival of strain 15-4 in response to Cr(VI).
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Affiliation(s)
- Shi-Weng Li
- School of Environmental and Municipal Engineering, Lanzhou Jiaotong University, Lanzhou, People's Republic of China. .,School of Chemical and Biological Engineering, Lanzhou Jiaotong University, Lanzhou, 730070, People's Republic of China. .,Key Laboratory of Extreme Environmental Microbial Resources and Engineering in Gansu Province, Lanzhou, 730000, People's Republic of China.
| | - Ya Wen
- School of Chemical and Biological Engineering, Lanzhou Jiaotong University, Lanzhou, 730070, People's Republic of China
| | - Yan Leng
- School of Chemical and Biological Engineering, Lanzhou Jiaotong University, Lanzhou, 730070, People's Republic of China
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14
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Xu R, Sun X, Häggblom MM, Dong Y, Zhang M, Yang Z, Xiao E, Xiao T, Gao P, Li B, Sun W. Metabolic potentials of members of the class Acidobacteriia in metal-contaminated soils revealed by metagenomic analysis. Environ Microbiol 2021; 24:803-818. [PMID: 34081382 DOI: 10.1111/1462-2920.15612] [Citation(s) in RCA: 18] [Impact Index Per Article: 6.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/07/2021] [Revised: 05/18/2021] [Accepted: 05/23/2021] [Indexed: 01/09/2023]
Abstract
The relative abundance of Acidobacteriia correlated positively with the concentrations of arsenic (As), mercury (Hg), chromium (Cr), copper (Cu) and other metals, suggesting their adaptation of the metal-rich environments. Metagenomic binning reconstructed 29 high-quality metagenome-assembled genomes (MAGs) associated with Acidobacteriia, providing an opportunity to study their metabolic potentials. These MAGs contained genes to transform As, Hg and Cr through oxidation, reduction, efflux and demethylation, suggesting the potential of Acidobacteriia to transform such metal(loid)s. Additionally, genes associated with alleviation of acidic and metal stress were also detected in these MAGs. Acidobacteriia may have the capabilities to resist or transform metal(loid)s in acidic metal-contaminated sites. Moreover, these genes encoding metal transformation could be also identified in the Acidobacteriia-associated MAGs from five additional metal-contaminated sites across Southwest China, as well as Acidobacteriia-associated reference genomes from the NCBI database, suggesting that the capability of metal transformation may be widespread among Acidobacteriia members. This discovery provides an understanding of metabolic potentials of the Acidobacteriia in acidic metal-rich sites.
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Affiliation(s)
- Rui Xu
- National-Regional Joint Engineering Research Center for Soil Pollution Control and Remediation in South China, Guangdong Key Laboratory of Integrated Agro-environmental Pollution Control and Management, Institute of Eco-environmental and Soil Sciences, Guangdong Academy of Sciences, Guangzhou, 510650, China.,Guangdong-Hong Kong-Macao Joint Laboratory for Environmental Pollution and Control, Guangzhou Institute of Geochemistry, Chinese Academy of Sciences, Guangzhou, 510640, China
| | - Xiaoxu Sun
- National-Regional Joint Engineering Research Center for Soil Pollution Control and Remediation in South China, Guangdong Key Laboratory of Integrated Agro-environmental Pollution Control and Management, Institute of Eco-environmental and Soil Sciences, Guangdong Academy of Sciences, Guangzhou, 510650, China.,Guangdong-Hong Kong-Macao Joint Laboratory for Environmental Pollution and Control, Guangzhou Institute of Geochemistry, Chinese Academy of Sciences, Guangzhou, 510640, China
| | - Max M Häggblom
- Department of Biochemistry and Microbiology, Rutgers, The State University of New Jersey, New Brunswick, New Jersey, USA
| | - Yiran Dong
- School of Environmental Studies, China University of Geosciences (Wuhan), Wuhan, 430074, China
| | - Miaomiao Zhang
- National-Regional Joint Engineering Research Center for Soil Pollution Control and Remediation in South China, Guangdong Key Laboratory of Integrated Agro-environmental Pollution Control and Management, Institute of Eco-environmental and Soil Sciences, Guangdong Academy of Sciences, Guangzhou, 510650, China.,Guangdong-Hong Kong-Macao Joint Laboratory for Environmental Pollution and Control, Guangzhou Institute of Geochemistry, Chinese Academy of Sciences, Guangzhou, 510640, China
| | - Zhaohui Yang
- College of Environmental Science and Engineering, Hunan University, Changsha, 410082, China
| | - Enzong Xiao
- Key Laboratory of Water Quality and Conservation in the Pearl River Delta, Ministry of Education, School of Environmental Science and Engineering, Guangzhou University, Guangzhou, 510006, China
| | - Tangfu Xiao
- Key Laboratory of Water Quality and Conservation in the Pearl River Delta, Ministry of Education, School of Environmental Science and Engineering, Guangzhou University, Guangzhou, 510006, China
| | - Pin Gao
- National-Regional Joint Engineering Research Center for Soil Pollution Control and Remediation in South China, Guangdong Key Laboratory of Integrated Agro-environmental Pollution Control and Management, Institute of Eco-environmental and Soil Sciences, Guangdong Academy of Sciences, Guangzhou, 510650, China.,Guangdong-Hong Kong-Macao Joint Laboratory for Environmental Pollution and Control, Guangzhou Institute of Geochemistry, Chinese Academy of Sciences, Guangzhou, 510640, China
| | - Baoqin Li
- National-Regional Joint Engineering Research Center for Soil Pollution Control and Remediation in South China, Guangdong Key Laboratory of Integrated Agro-environmental Pollution Control and Management, Institute of Eco-environmental and Soil Sciences, Guangdong Academy of Sciences, Guangzhou, 510650, China.,Guangdong-Hong Kong-Macao Joint Laboratory for Environmental Pollution and Control, Guangzhou Institute of Geochemistry, Chinese Academy of Sciences, Guangzhou, 510640, China
| | - Weimin Sun
- National-Regional Joint Engineering Research Center for Soil Pollution Control and Remediation in South China, Guangdong Key Laboratory of Integrated Agro-environmental Pollution Control and Management, Institute of Eco-environmental and Soil Sciences, Guangdong Academy of Sciences, Guangzhou, 510650, China.,Guangdong-Hong Kong-Macao Joint Laboratory for Environmental Pollution and Control, Guangzhou Institute of Geochemistry, Chinese Academy of Sciences, Guangzhou, 510640, China.,School of Environment, Henan Normal University, China.,Key Laboratory of Yellow River and Huai River Water Environment and Pollution Control, Ministry of Education, China
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15
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Modeling cometabolism of hexavalent chromium by iron reducing bacteria in tertiary substrate system. Sci Rep 2021; 11:10864. [PMID: 34035332 PMCID: PMC8149721 DOI: 10.1038/s41598-021-90137-2] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/19/2021] [Accepted: 03/31/2021] [Indexed: 11/08/2022] Open
Abstract
In this study, a bacterial strain Serratia sp. was employed for the reduction of synthetically prepared different concentration of Cr(VI) solution (10, 25, 40, 50 and 100 mg/L). Cometabolism study have been carried out in the binary substrate system as well as in the tertiary substrate system. The results revealed that when glucose was added as a co-substrate, at low Cr(VI) concentration, complete reduction was achieved followed by increased biomass growth, but when Cr(VI) concentration was increased to 100 mg/L, the reduction decline to 93%. But in presence of high carbon iron filings (HCIF) as co-substrate even at higher Cr(VI) concentration i.e. 100 mg/L, 100% reduction was achieved and the cell growth continued till 124 h. The study was illustrated via Monod growth kinetic model for tertiary substrate system and the kinetic parameters revealed that the HCIF and glucose combination showed least inhibition to hexavalent chromium reduction by Serratia sp.
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16
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John R, Rajan AP. Pseudomonas putida APRRJVITS11 as a potent tool in chromium (VI) removal from effluent wastewater. Prep Biochem Biotechnol 2021; 52:163-170. [PMID: 33969814 DOI: 10.1080/10826068.2021.1922918] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/21/2022]
Abstract
Bioremediation is an essential feature of microorganisms concerning contaminations in soil and water. The use of microorganisms has been proved to be an effective treatment of industrially released effluents comprising of heavy metals, such as chromium (VI). In the current study, seasonal variations were observed in the concentrations of chromium(VI) as the samples from selected locations showed an increase in mean concentration during the summer compared to the low mean during winter, suggesting excessive evaporation in the summer leading to the heavy metal accumulation. Among the 35 isolates obtained from tannery effluent contaminated wastewater sources the 3 unique strains identified as Streptococcus pyogenes strain APRRJVITS10, Pseudomonas putida strain APRRJVITS11, and Bacillus thuringiensis strain APRRJVITS15, showed tolerance toward chromium(VI) and the maximum tolerance for each strain was 1250 ppm. The media optimization through shake flask methods showed chromium(VI) (in 100 ml LB broth) removal of 47.82%, 48.11%, and 49.93% by S. pyogenes, P. putida, and B. thuringiensis respectively. Further, Pseudomonas putida showed chromium(VI) (in 1500 ml LB broth) removal of 50.48% in optimized conditions, proving to be highly potential for treating effluent wastewater for chromium(VI) removal.
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Affiliation(s)
- Rinaldo John
- Department of Biomedical Sciences, School of Bio Sciences and Technology, VIT, Vellore, India
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17
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Zhang B, Liu J, Sheng Y, Shi J, Dong H. Disentangling Microbial Syntrophic Mechanisms for Hexavalent Chromium Reduction in Autotrophic Biosystems. ENVIRONMENTAL SCIENCE & TECHNOLOGY 2021; 55:6340-6351. [PMID: 33866784 DOI: 10.1021/acs.est.1c00383] [Citation(s) in RCA: 26] [Impact Index Per Article: 8.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/12/2023]
Abstract
Hexavalent chromium [Cr(VI)] is one of the common heavy-metal contaminants in groundwater, and the availability of electron donors is considered to be a key parameter for Cr(VI) biotransformation. During the autotrophic remediation process, however, much remains to be illuminated about how complex syntrophic microbial communities couple Cr(VI) reduction with other elemental cycles. Two series of Cr(VI)-reducing groundwater bioreactors were independently amended by elemental sulfur and iron and inoculated with the same inoculum. After 160 days of incubation, both bioreactors showed similar archaea-dominating microbiota compositions, whereas a higher Cr(VI)-reducing rate and more methane production were detected in the Fe0-driven one. Metabolic reconstruction of 23 retrieved genomes revealed complex symbiotic relationships driving distinct elemental cycles coupled with Cr(VI) reduction in bioreactors. In both bioreactors, these Cr(VI) reducers were assumed to live in syntrophy with oxidizers of sulfur, iron, hydrogen, and volatile fatty acids and methane produced by carbon fixers and multitrophic methanogens, respectively. The significant difference in methane production was mainly due to the fact that the yielded sulfate greatly retarded acetoclastic methanogenesis in the S-bioreactor. These findings provide insights into mutualistic symbioses of carbon, sulfur, iron, and chromium metabolisms in groundwater systems and have implications for bioremediation of Cr(VI)-contaminated groundwater.
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Affiliation(s)
- Baogang Zhang
- School of Water Resources and Environment, Key Laboratory of Groundwater Circulation and Environmental Evolution (China University of Geosciences Beijing), Ministry of Education, Beijing 100083, China
| | - Jun Liu
- State Key Laboratory of Biogeology and Environmental Geology, China University of Geosciences, Beijing 100083, China
- Department of Geology and Environmental Earth Science, Miami University, Oxford, Ohio 45056, United States
| | - Yizhi Sheng
- Department of Geology and Environmental Earth Science, Miami University, Oxford, Ohio 45056, United States
| | - Jiaxin Shi
- School of Water Resources and Environment, Key Laboratory of Groundwater Circulation and Environmental Evolution (China University of Geosciences Beijing), Ministry of Education, Beijing 100083, China
| | - Hailiang Dong
- State Key Laboratory of Biogeology and Environmental Geology, China University of Geosciences, Beijing 100083, China
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18
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Shi K, Radhakrishnan M, Dai X, Rosen BP, Wang G. NemA Catalyzes Trivalent Organoarsenical Oxidation and Is Regulated by the Trivalent Organoarsenical-Selective Transcriptional Repressor NemR. ENVIRONMENTAL SCIENCE & TECHNOLOGY 2021; 55:6485-6494. [PMID: 33851826 PMCID: PMC8879406 DOI: 10.1021/acs.est.1c00574] [Citation(s) in RCA: 8] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/12/2023]
Abstract
Synthetic aromatic arsenicals such as roxarsone (Rox(V)) and nitarsone (Nit(V)) have been used as animal growth enhancers and herbicides. Microbes contribute to redox cycling between the relatively less toxic pentavalent and highly toxic trivalent arsenicals. In this study, we report the identification of nemRA operon from Enterobacter sp. Z1 and show that it is involved in trivalent organoarsenical oxidation. Expression of nemA is induced by chromate (Cr(VI)), Rox(III), and Nit(III). Heterologous expression of NemA in Escherichia coli confers resistance to Cr(VI), methylarsenite (MAs(III)), Rox(III), and Nit(III). Purified NemA catalyzes simultaneous Cr(VI) reduction and MAs(III)/Rox(III)/Nit(III) oxidation, and oxidation was enhanced in the presence of Cr(VI). The results of electrophoretic mobility shift assays and fluorescence assays demonstrate that the transcriptional repressor, NemR, binds to either Rox(III) or Nit(III). NemR has three conserved cysteine residues, Cys21, Cys106, and Cys116. Mutation of any of the three resulted in loss of response to Rox(III)/Nit(III), indicating that they form an Rox(III)/Nit(III) binding site. These results show that NemA is a novel trivalent organoarsenical oxidase that is regulated by the trivalent organoarsenical-selective repressor NemR. This discovery expands our knowledge of the molecular mechanisms of organoarsenical oxidation and provides a basis for studying the redox coupling of environmental toxic compounds.
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Affiliation(s)
- Kaixiang Shi
- State Key Laboratory of Agricultural Microbiology, College of Life Science and Technology, Huazhong Agricultural University, Wuhan 430070, P. R. China
- Department of Cellular Biology and Pharmacology, Herbert Wertheim College of Medicine, Florida International University, Miami, Florida 33199, United States
| | - Manohar Radhakrishnan
- Department of Cellular Biology and Pharmacology, Herbert Wertheim College of Medicine, Florida International University, Miami, Florida 33199, United States
| | - Xingli Dai
- State Key Laboratory of Agricultural Microbiology, College of Life Science and Technology, Huazhong Agricultural University, Wuhan 430070, P. R. China
| | - Barry P Rosen
- Department of Cellular Biology and Pharmacology, Herbert Wertheim College of Medicine, Florida International University, Miami, Florida 33199, United States
| | - Gejiao Wang
- State Key Laboratory of Agricultural Microbiology, College of Life Science and Technology, Huazhong Agricultural University, Wuhan 430070, P. R. China
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19
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Microbial Mechanisms for Remediation of Hexavalent Chromium and their Large-Scale Applications; Current Research and Future Directions. JOURNAL OF PURE AND APPLIED MICROBIOLOGY 2021. [DOI: 10.22207/jpam.15.1.32] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022] Open
Abstract
The increase of anthropogenic activities has led to the pollution of the environment by heavy metals, including chromium (Cr). There are two common oxidative states of Cr that can be found in industrial effluents the trivalent chromium Cr(III) and the hexavalent chromium Cr(VI). While the hexavalent chromium Cr(VI) is highly toxic and can trigger serious human health issues, its reduced form, the trivalent chromium Cr(III), is less toxic and insoluble. Leather tanning is an important industry in many developing countries and serves as a major source of Cr(VI) contamination. Globally, tannery factories generate approximately 40 million m3 of Cr-containing wastewater annually. While the physico-chemical treatments of tannery wastewater are not safe, produce toxic chemicals and require large amounts of chemical inputs, bioremediation using chromium-resistant bacteria (CRB) is safer, efficient and does not produce toxic intermediates. Chromium-resistant bacteria (CRB) utilise three mechanisms for Cr(VI) removal: biotransformation, biosorption and bioaccumulation. This review will evaluate the three Cr(VI) detoxification mechanisms used by bacteria, their limitations and assess their applications for large-scale remediation of Cr(VI). This can be helpful for understanding the nature of Cr(VI) remediation mechanisms used by bacteria, therefore, bridging the gap between laboratory findings and industrial application of microorganisms for Cr(VI) removal.
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20
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Rahman Z, Thomas L. Chemical-Assisted Microbially Mediated Chromium (Cr) (VI) Reduction Under the Influence of Various Electron Donors, Redox Mediators, and Other Additives: An Outlook on Enhanced Cr(VI) Removal. Front Microbiol 2021; 11:619766. [PMID: 33584585 PMCID: PMC7875889 DOI: 10.3389/fmicb.2020.619766] [Citation(s) in RCA: 20] [Impact Index Per Article: 6.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/21/2020] [Accepted: 12/16/2020] [Indexed: 12/13/2022] Open
Abstract
Chromium (Cr) (VI) is a well-known toxin to all types of biological organisms. Over the past few decades, many investigators have employed numerous bioprocesses to neutralize the toxic effects of Cr(VI). One of the main process for its treatment is bioreduction into Cr(III). Key to this process is the ability of microbial enzymes, which facilitate the transfer of electrons into the high valence state of the metal that acts as an electron acceptor. Many underlying previous efforts have stressed on the use of different external organic and inorganic substances as electron donors to promote Cr(VI) reduction process by different microorganisms. The use of various redox mediators enabled electron transport facility for extracellular Cr(VI) reduction and accelerated the reaction. Also, many chemicals have employed diverse roles to improve the Cr(VI) reduction process in different microorganisms. The application of aforementioned materials at the contaminated systems has offered a variety of influence on Cr(VI) bioremediation by altering microbial community structures and functions and redox environment. The collective insights suggest that the knowledge of appropriate implementation of suitable nutrients can strongly inspire the Cr(VI) reduction rate and efficiency. However, a comprehensive information on such substances and their roles and biochemical pathways in different microorganisms remains elusive. In this regard, our review sheds light on the contributions of various chemicals as electron donors, redox mediators, cofactors, etc., on microbial Cr(VI) reduction for enhanced treatment practices.
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Affiliation(s)
- Zeeshanur Rahman
- Department of Botany, Zakir Husain Delhi College, University of Delhi, Delhi, India
| | - Lebin Thomas
- Department of Botany, Hansraj College, University of Delhi, Delhi, India
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John R, Rajan AP. Effective sequestration of chromium by bacterial biosorption: a review. Prep Biochem Biotechnol 2020; 51:738-748. [DOI: 10.1080/10826068.2020.1861010] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/22/2022]
Affiliation(s)
- Rinaldo John
- Department of Bio-Medical Sciences, School of Bio Sciences and Technology, Vellore Institute of Technology, Vellore, India
| | - Anand Prem Rajan
- Department of Bio-Medical Sciences, School of Bio Sciences and Technology, Vellore Institute of Technology, Vellore, India
- CO2 and Green Technology Centre, Vellore Institute of Technology, Vellore, India
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Pei Y, Tao C, Ling Z, Yu Z, Ji J, Khan A, Mamtimin T, Liu P, Li X. Exploring novel Cr(VI) remediation genes for Cr(VI)-contaminated industrial wastewater treatment by comparative metatranscriptomics and metagenomics. THE SCIENCE OF THE TOTAL ENVIRONMENT 2020; 742:140435. [PMID: 32623159 DOI: 10.1016/j.scitotenv.2020.140435] [Citation(s) in RCA: 10] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 03/18/2020] [Revised: 06/17/2020] [Accepted: 06/20/2020] [Indexed: 06/11/2023]
Abstract
Microbial remediation is a promising method to treat Cr(VI) in industrial wastewater. The remediation efficiency and stress-resistance ability of Cr(VI) remediation genes in microbes are the limiting factors for their application in industrial wastewater treatment. To screen novel highly efficient Cr(VI) remediation genes, comparative metatranscriptomic and metagenomic analyses were performed on long-term Cr(VI)-contaminated riparian soil with/without additional Cr(VI) treatment. The most suitable Cr(VI) treatment time was determined to be 30 min according to the high quality RNA yield and fold changes in gene expression. Six novel genes, which had complete open reading frames (ORFs) in metagenomic libraries, were identified from unculturable microbes. In the phenotypic functional assay, all novel genes enhanced the Cr(VI) resistance/reduction ability of E. coli. In the industrial wastewater treatment, E-mcr and E-gsr presented at least 50% Cr(VI) removal efficiencies in the presence of 200-600 μM of Cr(VI), without a decrease in efficiency over 17 days. The stress resistance assay showed that gsr increased the growth rate of E. coli by at least 30% under different extreme conditions, and thus, gsr was identified as a general stress-response gene. In the Cr valence distribution assay, E-mcr presented ~40 μM higher extracellular Cr (III) compared to E-yieF. Additionally, transmission electron microscopy (TEM) of E-mcr showed bulk black agglomerates on the cell surface. Thus, mcr was identified as a membrane chromate reductase gene. This research provides a new idea for studying novel highly efficient contaminant remediation genes from unculturable microbes.
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Affiliation(s)
- Yaxin Pei
- Ministry of Education Key Laboratory of Cell Activities and Stress Adaptations, School of Life Sciences, Lanzhou University, Tianshuinanlu #222, Lanzhou 730000, Gansu, China; Key Laboratory for Resources Utilization Technology of Unconventional Water of Gansu province, Gansu Academy of Membrane Science and Technology, Duanjiatanlu #1272, Lanzhou 730000, Gansu, China
| | - Chen Tao
- State Key Laboratory of Environmental Chemistry and Ecotoxicology, Research Center for Eco-Environmental Sciences, Chinese Academy of Sciences, Shuangqinglu #18, Beijing 100085, China
| | - Zhenmin Ling
- Ministry of Education Key Laboratory of Cell Activities and Stress Adaptations, School of Life Sciences, Lanzhou University, Tianshuinanlu #222, Lanzhou 730000, Gansu, China; Key Laboratory for Resources Utilization Technology of Unconventional Water of Gansu province, Gansu Academy of Membrane Science and Technology, Duanjiatanlu #1272, Lanzhou 730000, Gansu, China
| | - Zhengsheng Yu
- Key Laboratory for Resources Utilization Technology of Unconventional Water of Gansu province, Gansu Academy of Membrane Science and Technology, Duanjiatanlu #1272, Lanzhou 730000, Gansu, China
| | - Jing Ji
- Key Laboratory for Resources Utilization Technology of Unconventional Water of Gansu province, Gansu Academy of Membrane Science and Technology, Duanjiatanlu #1272, Lanzhou 730000, Gansu, China; Gansu Key Laboratory of Biomonitoring and Bioremediation for Environment Pollution, School of Life Science, Lanzhou University, Tianshuinanlu #222, Lanzhou 730000, Gansu, China
| | - Aman Khan
- Key Laboratory for Resources Utilization Technology of Unconventional Water of Gansu province, Gansu Academy of Membrane Science and Technology, Duanjiatanlu #1272, Lanzhou 730000, Gansu, China; Gansu Key Laboratory of Biomonitoring and Bioremediation for Environment Pollution, School of Life Science, Lanzhou University, Tianshuinanlu #222, Lanzhou 730000, Gansu, China
| | - Tursunay Mamtimin
- Ministry of Education Key Laboratory of Cell Activities and Stress Adaptations, School of Life Sciences, Lanzhou University, Tianshuinanlu #222, Lanzhou 730000, Gansu, China; Gansu Key Laboratory of Biomonitoring and Bioremediation for Environment Pollution, School of Life Science, Lanzhou University, Tianshuinanlu #222, Lanzhou 730000, Gansu, China
| | - Pu Liu
- Ministry of Education Key Laboratory of Cell Activities and Stress Adaptations, School of Life Sciences, Lanzhou University, Tianshuinanlu #222, Lanzhou 730000, Gansu, China
| | - Xiangkai Li
- Ministry of Education Key Laboratory of Cell Activities and Stress Adaptations, School of Life Sciences, Lanzhou University, Tianshuinanlu #222, Lanzhou 730000, Gansu, China; Key Laboratory for Resources Utilization Technology of Unconventional Water of Gansu province, Gansu Academy of Membrane Science and Technology, Duanjiatanlu #1272, Lanzhou 730000, Gansu, China.
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Marques CR, Wibowo D, Rubio-Reyes P, Serafim LS, Soares AMVM, Rehm BHA. Bacterially assembled biopolyester nanobeads for removing cadmium from water. WATER RESEARCH 2020; 186:116357. [PMID: 32916618 DOI: 10.1016/j.watres.2020.116357] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 06/01/2020] [Revised: 08/24/2020] [Accepted: 08/29/2020] [Indexed: 06/11/2023]
Abstract
Cadmium (Cd)-contaminated waterbodies are a worldwide concern for the environment, impacting human health. To address the need for efficient, sustainable and cost-effective remediation measures, we developed innovative Cd bioremediation agents by engineering Escherichia coli to assemble poly(3-hydroxybutyric acid) (PHB) beads densely coated with Cd-binding peptides. This was accomplished by translational fusion of Cd-binding peptides to the N- or C-terminus of a PHB synthase that catalyzes PHB synthesis and mediates assembly of Cd2 or Cd1 coated PHB beads, respectively. Cd1 beads showed greater Cd adsorption with 441 nmol Cd mg-1 bead mass when compared to Cd2 beads (334 nmol Cd mg-1 bead-mass) and plain beads (238 nmol Cd mg-1 bead-mass). The Cd beads were not ecotoxic and did attenuate Cd-spiked solutions toxicity. Overall, the bioengineered beads provide a means to remediate Cd-contaminated sites, can be cost-effectively produced at large scale, and offer a biodegradable and safe alternative to synthetic ecotoxic treatments.
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Affiliation(s)
- Catarina R Marques
- CESAM - Centre of Marine and Environmental Studies, Department of Biology, University of Aveiro, Santiago University Campus, 3810-193 Aveiro, Portugal.
| | - David Wibowo
- Centre for Cell Factories and Biopolymers, Griffith Institute for Drug Discovery, Griffith University, Nathan, QLD 4111, Australia
| | - Patricia Rubio-Reyes
- Malaghan Institute of Medical Research, Gate 7, Victoria University Central Services Building, Kelburn, Wellington 6012, New Zealand
| | - Luísa S Serafim
- CICECO - Aveiro Institute of Materials, Chemistry Department, University of Aveiro, 3810-193 Aveiro, Portugal
| | - Amadeu M V M Soares
- CESAM - Centre of Marine and Environmental Studies, Department of Biology, University of Aveiro, Santiago University Campus, 3810-193 Aveiro, Portugal
| | - Bernd H A Rehm
- Centre for Cell Factories and Biopolymers, Griffith Institute for Drug Discovery, Griffith University, Nathan, QLD 4111, Australia
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NfoR: Chromate Reductase or Flavin Mononucleotide Reductase? Appl Environ Microbiol 2020; 86:AEM.01758-20. [PMID: 32887719 PMCID: PMC7642083 DOI: 10.1128/aem.01758-20] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/20/2020] [Accepted: 09/01/2020] [Indexed: 01/07/2023] Open
Abstract
Soil bacteria can detoxify Cr(VI) ions by reduction. Within the last 2 decades, numerous reports of chromate reductase enzymes have been published. These reports describe catalytic reduction of chromate ions by specific enzymes. These enzymes each have sequence similarity to known redox-active flavoproteins. We investigated the enzyme NfoR from Staphylococcus aureus, which was reported to be upregulated in chromate-rich soils and to have chromate reductase activity (H. Han, Z. Ling, T. Zhou, R. Xu, et al., Sci Rep 7:15481, 2017, https://doi.org/10.1038/s41598-017-15588-y). We show that NfoR has structural similarity to known flavin mononucleotide (FMN) reductases and reduces FMN as a substrate. NfoR binds FMN with a dissociation constant of 0.4 μM. The enzyme then binds NADPH with a dissociation constant of 140 μM and reduces the flavin at a rate of 1,350 s-1 Turnover of the enzyme is apparently limited by the rate of product release that occurs, with a net rate constant of 0.45 s-1 The rate of product release limits the rate of observed chromate reduction, so the net rate of chromate reduction by NfoR is orders of magnitude lower than when this process occurs in solution. We propose that NfoR is an FMN reductase and that the criterion required to define chromate reduction as enzymatic has not been met. That NfoR expression is increased in the presence of chromate suggests that the survival adaption was to increase the net rate of chromate reduction by facile, adventitious redox processes.IMPORTANCE Chromate is a toxic by-product of multiple industrial processes. Chromate reduction is an important biological activity that ameliorates Cr(VI) toxicity. Numerous researchers have identified chromate reductase activity by observing chromate reduction. However, all identified chromate reductase enzymes have flavin as a cofactor or use a flavin as a substrate. We show here that NfoR, an enzyme claimed to be a chromate reductase, is in fact an FMN reductase. In addition, we show that reduction of a flavin is a viable way to transfer electrons to chromate but that it is unlikely to be the native function of enzymes. We propose that upregulation of a redox-active flavoprotein is a viable means to detoxify chromate that relies on adventitious reduction that is not catalyzed.
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Feng P, Ye Z, Han H, Ling Z, Zhou T, Zhao S, Virk AK, Kakade A, Abomohra AEF, El-Dalatony MM, Salama ES, Liu P, Li X. Tibet plateau probiotic mitigates chromate toxicity in mice by alleviating oxidative stress in gut microbiota. Commun Biol 2020; 3:242. [PMID: 32415160 PMCID: PMC7229148 DOI: 10.1038/s42003-020-0968-3] [Citation(s) in RCA: 22] [Impact Index Per Article: 5.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/29/2019] [Accepted: 04/24/2020] [Indexed: 12/24/2022] Open
Abstract
Heavy metal contamination in food endangers human health. Probiotics can protect animals and human against heavy metals, but the detoxification mechanism has not been fully clarified. Here, mice were supplemented with Pediococcus acidilactici strain BT36 isolated from Tibetan plateau yogurt, with strong antioxidant activity but no chromate reduction ability for 20 days to ensure gut colonization. Strain BT36 decreased chromate accumulation, reduced oxidative stress, and attenuated histological damage in the liver of mice. 16S rRNA and metatranscriptome sequencing analysis of fecal microbiota showed that BT36 reversed Cr(VI)-induced changes in gut microbial composition and metabolic activity. Specifically, BT36 recovered the expressions of 788 genes, including 34 inherent Cr remediation-relevant genes. Functional analysis of 10 unannotated genes regulated by BT36 suggested the existence of a new Cr(VI)-reduction gene in the gut microbiota. Thus, BT36 can modulate the gut microbiota in response to Cr(VI) induced oxidative stress and protect against Cr toxicity.
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Affiliation(s)
- Pengya Feng
- Ministry of Education Key Laboratory of Cell Activities and Stress Adaptations, School of Life Science, Lanzhou University, Lanzhou, Gansu, 730000, P. R. China
| | - Ze Ye
- Ministry of Education Key Laboratory of Cell Activities and Stress Adaptations, School of Life Science, Lanzhou University, Lanzhou, Gansu, 730000, P. R. China
| | - Huawen Han
- Ministry of Education Key Laboratory of Cell Activities and Stress Adaptations, School of Life Science, Lanzhou University, Lanzhou, Gansu, 730000, P. R. China
| | - Zhenmin Ling
- Ministry of Education Key Laboratory of Cell Activities and Stress Adaptations, School of Life Science, Lanzhou University, Lanzhou, Gansu, 730000, P. R. China
| | - Tuoyu Zhou
- Ministry of Education Key Laboratory of Cell Activities and Stress Adaptations, School of Life Science, Lanzhou University, Lanzhou, Gansu, 730000, P. R. China
| | - Shuai Zhao
- Ministry of Education Key Laboratory of Cell Activities and Stress Adaptations, School of Life Science, Lanzhou University, Lanzhou, Gansu, 730000, P. R. China
| | - Amanpreet Kaur Virk
- Faculty of Applied Sciences and Biotechnology, Shoolini University of Biotechnology and Management Sciences, Solan, 173212, Himachal Pradesh, India
| | - Apurva Kakade
- Ministry of Education Key Laboratory of Cell Activities and Stress Adaptations, School of Life Science, Lanzhou University, Lanzhou, Gansu, 730000, P. R. China
| | | | - Marwa M El-Dalatony
- Department of Earth Resources and Environmental Engineering, Hanyang University, Seoul, 04763, South Korea
| | - Ei-Sayed Salama
- Department of Occupational and Environmental Health, School of Public Health, Lanzhou University, Lanzhou, Gansu, 730000, P. R. China
| | - Pu Liu
- Ministry of Education Key Laboratory of Cell Activities and Stress Adaptations, School of Life Science, Lanzhou University, Lanzhou, Gansu, 730000, P. R. China.
| | - Xiangkai Li
- Ministry of Education Key Laboratory of Cell Activities and Stress Adaptations, School of Life Science, Lanzhou University, Lanzhou, Gansu, 730000, P. R. China.
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26
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Wong JX, Ogura K, Chen S, Rehm BHA. Bioengineered Polyhydroxyalkanoates as Immobilized Enzyme Scaffolds for Industrial Applications. Front Bioeng Biotechnol 2020; 8:156. [PMID: 32195237 PMCID: PMC7064635 DOI: 10.3389/fbioe.2020.00156] [Citation(s) in RCA: 19] [Impact Index Per Article: 4.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/20/2019] [Accepted: 02/14/2020] [Indexed: 12/11/2022] Open
Abstract
Enzymes function as biocatalysts and are extensively exploited in industrial applications. Immobilization of enzymes using support materials has been shown to improve enzyme properties, including stability and functionality in extreme conditions and recyclability in biocatalytic processing. This review focuses on the recent advances utilizing the design space of in vivo self-assembled polyhydroxyalkanoate (PHA) particles as biocatalyst immobilization scaffolds. Self-assembly of biologically active enzyme-coated PHA particles is a one-step in vivo production process, which avoids the costly and laborious in vitro chemical cross-linking of purified enzymes to separately produced support materials. The homogeneous orientation of enzymes densely coating PHA particles enhances the accessibility of catalytic sites, improving enzyme function. The PHA particle technology has been developed into a remarkable scaffolding platform for the design of cost-effective designer biocatalysts amenable toward robust industrial bioprocessing. In this review, the PHA particle technology will be compared to other biological supramolecular assembly-based technologies suitable for in vivo enzyme immobilization. Recent progress in the fabrication of biological particulate scaffolds using enzymes of industrial interest will be summarized. Additionally, we outline innovative approaches to overcome limitations of in vivo assembled PHA particles to enable fine-tuned immobilization of multiple enzymes to enhance performance in multi-step cascade reactions, such as those used in continuous flow bioprocessing.
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Affiliation(s)
- Jin Xiang Wong
- School of Fundamental Sciences, Massey University, Palmerston North, New Zealand
- MacDiarmid Institute of Advanced Materials and Nanotechnology, Victoria University of Wellington, Wellington, New Zealand
| | - Kampachiro Ogura
- School of Fundamental Sciences, Massey University, Palmerston North, New Zealand
| | - Shuxiong Chen
- Centre for Cell Factories and Biopolymers, Griffith Institute for Drug Discovery, Griffith University, Nathan, QLD, Australia
| | - Bernd H. A. Rehm
- Centre for Cell Factories and Biopolymers, Griffith Institute for Drug Discovery, Griffith University, Nathan, QLD, Australia
- Menzies Health Institute Queensland (MHIQ), Griffith University, Gold Coast Campus, Southport, QLD, Australia
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27
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Reduction of chromium-VI by chromium-resistant Escherichia coli FACU: a prospective bacterium for bioremediation. Folia Microbiol (Praha) 2020; 65:687-696. [DOI: 10.1007/s12223-020-00771-y] [Citation(s) in RCA: 17] [Impact Index Per Article: 4.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/26/2019] [Accepted: 01/16/2020] [Indexed: 01/04/2023]
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Zhu Y, Yan J, Xia L, Zhang X, Luo L. Mechanisms of Cr(VI) reduction by Bacillus sp. CRB-1, a novel Cr(VI)-reducing bacterium isolated from tannery activated sludge. ECOTOXICOLOGY AND ENVIRONMENTAL SAFETY 2019; 186:109792. [PMID: 31629191 DOI: 10.1016/j.ecoenv.2019.109792] [Citation(s) in RCA: 39] [Impact Index Per Article: 7.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 07/27/2019] [Revised: 10/07/2019] [Accepted: 10/10/2019] [Indexed: 06/10/2023]
Abstract
Cr(VI) reduction by microorganisms has been extensively reported, however, the mechanism of Cr(VI) reduction varies among different microorganisms. In this study, a Cr(VI)-reducing bacterium identified as Bacillus sp. was isolated from tannery activated sludge, strain CRB-1 was able to completely reduce 50 mg/L of Cr(VI) within 24 h under aerobic conditions and exhibited considerable Cr(VI) removal efficiency in the pH range from 7.0 to 9.0, temperature 24-42 °C. Cr(VI) reduction assays with resting cells, permeabilized cells, and subcellular fractions suggested that Cr(VI) reduction mainly occurred in the cytoplasm. According to qRT-PCR analysis, a chrA gene and a nitR2 gene were up-regulated under Cr(VI) stress. Heterologous expression of the chrA gene and the nitR2 gene indicated that ChrA was associated with Cr(VI) resistance, while NitR2 was responsible for Cr(VI) reduction. Furthermore, soluble end products were detected. On the basis of FTIR, it was speculated that the formation of soluble end products may be due to the complexation of EPS with Cr(III). Consequently, the Cr(VI)-reducing ability of strain CRB-1 and its chromate reductases enables CRB-1 a potential candidate for Cr(VI) bioremediation.
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Affiliation(s)
- Yunfei Zhu
- School of Biology and Biological Engineering, South China University of Technology, Guangzhou, 510006, China
| | - Junwei Yan
- School of Biology and Biological Engineering, South China University of Technology, Guangzhou, 510006, China
| | - Li Xia
- School of Biology and Biological Engineering, South China University of Technology, Guangzhou, 510006, China
| | - Xiang Zhang
- School of Biology and Biological Engineering, South China University of Technology, Guangzhou, 510006, China
| | - Lixin Luo
- School of Biology and Biological Engineering, South China University of Technology, Guangzhou, 510006, China.
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Güngör T, Önder FC, Tokay E, Gülhan ÜG, Hacıoğlu N, Tok TT, Çelik A, Köçkar F, Ay M. PRODRUGS FOR NITROREDUCTASE BASED CANCER THERAPY- 2: Novel amide/Ntr combinations targeting PC3 cancer cells. Eur J Med Chem 2019; 171:383-400. [DOI: 10.1016/j.ejmech.2019.03.035] [Citation(s) in RCA: 13] [Impact Index Per Article: 2.6] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/28/2018] [Revised: 02/26/2019] [Accepted: 03/14/2019] [Indexed: 02/06/2023]
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Chai L, Ding C, Li J, Yang Z, Shi Y. Multi-omics response of Pannonibacter phragmitetus BB to hexavalent chromium. ENVIRONMENTAL POLLUTION (BARKING, ESSEX : 1987) 2019; 249:63-73. [PMID: 30878863 DOI: 10.1016/j.envpol.2019.03.005] [Citation(s) in RCA: 46] [Impact Index Per Article: 9.2] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 10/25/2018] [Revised: 02/25/2019] [Accepted: 03/03/2019] [Indexed: 05/27/2023]
Abstract
The release of hexavalent chromium [Cr(VI)] into water bodies poses a major threat to the environment and human health. However, studies of the biological response to Cr(VI) are limited. In this study, a toxic bacterial mechanism of Cr(VI) was investigated using Pannonibacter phragmitetus BB (hereafter BB), which was isolated from chromate slag. The maximum Cr(VI) concentrations with respect to the resistance and reduction by BB are 4000 mg L-1 and 2500 mg L-1, respectively. In the BB genome, more genes responsible for Cr(VI) resistance and reduction are observed compared with other P. phragmitetus strains. A total of 361 proteins were upregulated to respond to Cr(VI) exposure, including enzymes for Cr(VI) uptake, intracellular reduction, ROS detoxification, DNA repair, and Cr(VI) efflux and proteins associated with novel mechanisms involving extracellular reduction mediated by electron transfer, quorum sensing, and chemotaxis. Based on metabolomic analysis, 174 metabolites were identified. Most of the upregulated metabolites are involved in amino acid, glucose, lipid, and energy metabolisms. The results show that Cr(VI) induces metabolite production, while metabolites promote Cr(VI) reduction. Overall, multi-enzyme expression and metabolite production by BB contribute to its high ability to resist/reduce Cr(VI). This study provides details supporting the theory of Cr(VI) reduction and a theoretical basis for the efficient bioremoval of Cr(VI) from the environment.
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Affiliation(s)
- Liyuan Chai
- Institute of Environmental Science and Engineering, School of Metallurgy and Environment, Central South University, 410083, Changsha, China; National Engineering Research Center for Heavy Metals Pollution Control and Treatment, 410083, Changsha, China
| | - Chunlian Ding
- Institute of Environmental Science and Engineering, School of Metallurgy and Environment, Central South University, 410083, Changsha, China
| | - Jiawei Li
- Institute of Environmental Science and Engineering, School of Metallurgy and Environment, Central South University, 410083, Changsha, China
| | - Zhihui Yang
- Institute of Environmental Science and Engineering, School of Metallurgy and Environment, Central South University, 410083, Changsha, China; National Engineering Research Center for Heavy Metals Pollution Control and Treatment, 410083, Changsha, China
| | - Yan Shi
- Institute of Environmental Science and Engineering, School of Metallurgy and Environment, Central South University, 410083, Changsha, China; National Engineering Research Center for Heavy Metals Pollution Control and Treatment, 410083, Changsha, China.
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31
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Fernández PM, Viñarta SC, Bernal AR, Cruz EL, Figueroa LIC. Bioremediation strategies for chromium removal: Current research, scale-up approach and future perspectives. CHEMOSPHERE 2018; 208:139-148. [PMID: 29864705 DOI: 10.1016/j.chemosphere.2018.05.166] [Citation(s) in RCA: 145] [Impact Index Per Article: 24.2] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 02/07/2018] [Revised: 05/16/2018] [Accepted: 05/27/2018] [Indexed: 05/25/2023]
Abstract
Industrial applications and commercial processes release a lot of chromium into the environment (soil, surface water or atmosphere) and resulting in serious human diseases because of their toxicity. Biological Cr-removal offers an alternative to traditional physic-chemical methods. This is considered as a sustainable technology of lower impact on the environment. Resistant microorganisms (e.g. bacteria, fungi, and algae) have been most extensively studied from this characteristic. Several mechanisms were developed by microorganisms to deal with chromium toxicity. These tools include biotransformation (reduction or oxidation), bioaccumulation and/or biosorption, and are considered as an alternative to remove the heavy metal. The aim of this review is summarizes Cr(VI)-bioremediation technologies oriented on practical applications at larger scale technologies. In the same way, the most relevant results of several investigations focused on process feasibility and the robustness of different systems (reactors and pilot scale) designed for chromium-removal capacity are highlighted.
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Affiliation(s)
- Pablo M Fernández
- Planta Piloto de Procesos Industriales Microbiológicos PROIMI-CONICET, Av. Belgrano y Caseros, T4001MVB San Miguel de Tucumán, Tucumán, Argentina; Facultad de Ciencias Exactas y Naturales, Universidad Nacional de Catamarca, Av. Belgrano 300, 4700 San Fernando del Valle de Catamarca, Catamarca, Argentina.
| | - Silvana C Viñarta
- Planta Piloto de Procesos Industriales Microbiológicos PROIMI-CONICET, Av. Belgrano y Caseros, T4001MVB San Miguel de Tucumán, Tucumán, Argentina; Facultad de Ciencias Exactas y Naturales, Universidad Nacional de Catamarca, Av. Belgrano 300, 4700 San Fernando del Valle de Catamarca, Catamarca, Argentina.
| | - Anahí R Bernal
- Planta Piloto de Procesos Industriales Microbiológicos PROIMI-CONICET, Av. Belgrano y Caseros, T4001MVB San Miguel de Tucumán, Tucumán, Argentina.
| | - Elías L Cruz
- Planta Piloto de Procesos Industriales Microbiológicos PROIMI-CONICET, Av. Belgrano y Caseros, T4001MVB San Miguel de Tucumán, Tucumán, Argentina.
| | - Lucía I C Figueroa
- Planta Piloto de Procesos Industriales Microbiológicos PROIMI-CONICET, Av. Belgrano y Caseros, T4001MVB San Miguel de Tucumán, Tucumán, Argentina; Facultad de Bioquímica, Química y Farmacia, Universidad Nacional de Tucumán, Ayacucho 450, 4000 San Miguel de Tucumán, Tucumán, Argentina.
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32
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Shi L, Xue J, Liu B, Dong P, Wen Z, Shen Z, Chen Y. Hydrogen ions and organic acids secreted by ectomycorrhizal fungi, Pisolithus sp1, are involved in the efficient removal of hexavalent chromium from waste water. ECOTOXICOLOGY AND ENVIRONMENTAL SAFETY 2018; 161:430-436. [PMID: 29908454 DOI: 10.1016/j.ecoenv.2018.06.004] [Citation(s) in RCA: 14] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 01/29/2018] [Revised: 05/30/2018] [Accepted: 06/02/2018] [Indexed: 05/27/2023]
Abstract
Pisolithus sp1 is an ectomycorrhizal (ECM) fungi that was chosen during a screening test of six strains of ECM fungi due to its ability to tolerate and remove hexavalent chromium (Cr(VI)). The physiological responses of Pisolithus sp1 to Cr(VI) exposure, the relationship between Pisolithus sp1 and exogenously added organic acids (EAOAs) or Na3VO4 (H+-ATPase inhibitor) and the ability of Pisolithus sp1 to reduce Cr(VI) in liquid culture were also investigated. Hydrogen ions (H+), which were produced directly by Pisolithus sp1, reduced the pH of the medium and played an important role in Cr(VI) reduction; however, Na3VO4 significantly inhibited this process and resulted in a decrease in the Cr(VI) reduction rates. Organic acids were secreted after the reduction in Cr(VI) by Pisolithus sp1, and EAOAs did not significantly affect Cr(VI) reduction; those results revealed the secondary role of organic acids in Cr(VI) reduction. The Cr(VI) removal rate of Pisolithus sp1 approached 99% after Cr(VI) treatment for 12 days. Overall, 75% of the Cr(VI) removal was due to extracellular reduction and 24% was due to adsorption. The results of this study provide a strong basis for using Cr(VI)-tolerant and Cr(VI)-reducing fungi, as well as ectomycorrhiza, in the remediation of Cr(VI)-contaminated sites.
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Affiliation(s)
- Liang Shi
- College of Life Sciences, Nanjing Agiricultural University, China
| | - Jiawang Xue
- College of Life Sciences, Nanjing Agiricultural University, China
| | - Binhao Liu
- College of Life Sciences, Nanjing Agiricultural University, China
| | - Pengcheng Dong
- College of Life Sciences, Nanjing Agiricultural University, China
| | - Zhugui Wen
- Jiangsu Coastal Area Institute of Agricultural Sciences, Yancheng, Jiangsu, 224002, China
| | - Zhenguo Shen
- College of Life Sciences, Nanjing Agiricultural University, China; Jiangsu Collaborative Innovation Center for Solid Organic Waste Resource, Nanjing Agiricultural University, China; National Joint Local Engineering Research Center for Rural Land Resources Use and Consolidation, Nanjing Agricultural University, Nanjing Agiricultural University, Nanjing 210095, China
| | - Yahua Chen
- College of Life Sciences, Nanjing Agiricultural University, China; Jiangsu Collaborative Innovation Center for Solid Organic Waste Resource, Nanjing Agiricultural University, China; National Joint Local Engineering Research Center for Rural Land Resources Use and Consolidation, Nanjing Agricultural University, Nanjing Agiricultural University, Nanjing 210095, China.
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Copper (II) binding of NAD(P)H- flavin oxidoreductase (NfoR) enhances its Cr (VI)-reducing ability. Sci Rep 2017; 7:15481. [PMID: 29133854 PMCID: PMC5684319 DOI: 10.1038/s41598-017-15588-y] [Citation(s) in RCA: 15] [Impact Index Per Article: 2.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/22/2017] [Accepted: 10/23/2017] [Indexed: 12/16/2022] Open
Abstract
Microbes can reduce hexavalent chromium Cr (VI) to the less toxic and soluble trivalent Cr (III). Copper stimulates microbial reduction of Cr (VI) by the Bacillus, Ochrobactrum, and Gluconobacter species; however, the mechanism remains unclear. In our study, the rate of Cr (VI) reduction by Staphylococcus aureus LZ-01 was increased by 210 % when supplemented with 60 μM Cu (II). A putative NAD(P)H-flavin oxidoreductase gene (nfoR) was upregulated under Cr (VI) stress. NfoR-knockout mutant displayed impaired reduction of Cr (VI) and Cu (II)-enhanced Cr (VI) reduction by nfoR isogenic mutant was attenuated in the presence of Cu (II). In vitro tests showed an increased Vmax value of 25.22 μM min−1 mg−1 NfoR in the presence of Cu (II). Together, these results indicate that NfoR is responsible for Cu (II) enhancement. Isothermal titration calorimetry (ITC) assays confirmed the interaction of NfoR with Cu (II) at the dissociation constant of 85.5 μM. Site-directed mutagenesis indicates that His100, His128, and Met165 residues may be important for Cu (II) binding, while Cys163 is necessary for the FMN binding of NfoR. These findings show that Cu (II)-enhanced NfoR belongs to a new branch of Cr (VI) reductases and profoundly influences Cr (VI) reduction.
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Kutralam-Muniasamy G, Perez-Guevara F. Recombinant surface engineering to enhance and expand the potential of biologically produced nanoparticles: A review. Process Biochem 2017. [DOI: 10.1016/j.procbio.2016.07.002] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 01/12/2023]
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de Alencar FLS, Navoni JA, do Amaral VS. The use of bacterial bioremediation of metals in aquatic environments in the twenty-first century: a systematic review. ENVIRONMENTAL SCIENCE AND POLLUTION RESEARCH INTERNATIONAL 2017; 24:16545-16559. [PMID: 28540556 DOI: 10.1007/s11356-017-9129-8] [Citation(s) in RCA: 9] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 01/12/2017] [Accepted: 04/26/2017] [Indexed: 06/07/2023]
Abstract
Metal pollution is a current environmental issue as a consequence of unregulated anthropic activiy. A wide range of bioremediation strategies have been successfully implemented to recover contaminated areas. Among them, bacterial bioremediation stands out as a promising tool to confront these types of concerns. This study aimed to compare and discuss worldwide scientific evolution of bacterial potential for metal bioremediation in aquatic ecosystems. The study consisted of a systematic review, elaborated through a conceptual hypothesis model, during the period from 2000 to 2016, using PubMed, MEDLINE, and SciELO databases as data resources. The countries with the largest number of reports included in this work were India and the USA. Industrial wastewater discharge was the main subject associated to metal contamination/pollution and where bacterial bioremediations have mostly been applied. Biosorption is the main bioremediation mechanism described. Bacterial adaptation to metal presence was discussed in all the selected studies, and chromium was the most researched bioremedied substrate. Gram-negative Pseudomonas aeruginosas and the Gram-positive Bacillus subtilis bacteria were microorganisms with the greatest applicability for metal bioremediation. Most reports involved the study of genes and/or proteins related to metal metabolism and/or resistence, and Chromobacterium violaceum was the most studied. The present work shows the relevance of metal bacterial bioremediation through the high number of studies aimed at understanding the microbiological mechanisms involved. Moreover, the developed processes applied in removal and/or reducing the resulting environmental metal contaminant/pollutant load have become a current and increasingly biotechnological issue for recovering impacted areas.
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Affiliation(s)
| | - Julio Alejandro Navoni
- Development and Environment, Biosciences Center, Federal University of Rio Grande do Norte, Natal, RN, Brazil
| | - Viviane Souza do Amaral
- Development and Environment, Biosciences Center, Federal University of Rio Grande do Norte, Natal, RN, Brazil.
- Department of Cell Biology and Genetics, Federal University of Rio Grande do Norte (UFRN), Natal, RN, Brazil.
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Rehm FBH, Chen S, Rehm BHA. Bioengineering toward direct production of immobilized enzymes: A paradigm shift in biocatalyst design. Bioengineered 2017; 9:6-11. [PMID: 28463573 PMCID: PMC5972917 DOI: 10.1080/21655979.2017.1325040] [Citation(s) in RCA: 22] [Impact Index Per Article: 3.1] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/30/2022] Open
Abstract
The need for cost-effectively produced and improved biocatalysts for industrial, pharmaceutical and environmental processes is steadily increasing. While enzyme properties themselves can be improved via protein engineering, immobilization by attachment to carrier materials remains a critical step for stabilization and process implementation. A new emerging immobilization approach, the in situ immobilization, enables simultaneous production of highly active enzymes and carrier materials using bioengineering/synthetic biology of microbial cells. In situ enzyme immobilization holds the promise of cost-effective production of highly functional immobilized biocatalysts for uses such as in bioremediation, drug synthesis, bioenergy and food processing.
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Affiliation(s)
- Fabian B H Rehm
- a Institute for Molecular Bioscience, The University of Queensland , St Lucia , Brisbane , Australia
| | - Shuxiong Chen
- b Institute of Fundamental Sciences, Massey University , Palmerston North , New Zealand
| | - Bernd H A Rehm
- b Institute of Fundamental Sciences, Massey University , Palmerston North , New Zealand.,c Australian Institute of Innovative Materials, University of Wollongong , Australia
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Rehm BHA. Bioengineering towards self-assembly of particulate vaccines. Curr Opin Biotechnol 2017; 48:42-53. [PMID: 28365472 DOI: 10.1016/j.copbio.2017.03.018] [Citation(s) in RCA: 23] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/06/2017] [Revised: 02/20/2017] [Accepted: 03/15/2017] [Indexed: 02/07/2023]
Abstract
There is an unmet demand for safe and efficient vaccines for prevention of various infectious diseases. Subunit vaccines comprise selected pathogen specific antigens are a safe alternative to whole organism vaccines. However they often lack immunogenicity. Natural and synthetic self-assembling polymers and proteins will be reviewed in view their use to encapsulate and/or display antigens to serve as immunogenic antigen carriers for induction of protective immunity. Recent advances made in in vivo assembly of antigen-displaying polyester inclusions will be a focus. Particulate vaccines are inherently immunogenic due to enhanced uptake by antigen presenting cells which process antigens mediating adaptive immune responses. Bioengineering approaches enable the design of tailor-made particulate vaccines to fine tune immune responses towards protective immunity.
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Affiliation(s)
- Bernd H A Rehm
- Institute of Fundamental Sciences, Massey University, Palmerston North, New Zealand.
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Thatoi HN, Pradhan SK. Detoxification and Bioremediation of Hexavalent Chromium Using Microbes and Their Genes: An Insight into Genomic, Proteomic and Bioinformatics Studies. Microb Biotechnol 2017. [DOI: 10.1007/978-981-10-6847-8_13] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/28/2023] Open
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Yu X, Jiang Y, Huang H, Shi J, Wu K, Zhang P, Lv J, Li H, He H, Liu P, Li X. Simultaneous aerobic denitrification and Cr(VI) reduction by Pseudomonas brassicacearum LZ-4 in wastewater. BIORESOURCE TECHNOLOGY 2016; 221:121-129. [PMID: 27639231 DOI: 10.1016/j.biortech.2016.09.037] [Citation(s) in RCA: 57] [Impact Index Per Article: 7.1] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 07/29/2016] [Revised: 09/07/2016] [Accepted: 09/08/2016] [Indexed: 06/06/2023]
Abstract
Inorganic nitrogen and heavy metals pervasively co-exist in industrial and domestic wastewaters. In this work, Pseudomonas brassicacearum LZ-4 was tested for the simultaneous reduction of Cr(VI) and nitrate. Nitrate was found to be the best inorganic nitrogen source for strain LZ-4, and could promote Cr(VI) reduction. Cr(VI) had a low degree of inhibition on denitrification, and even 50mgL-1 Cr(VI) did not inhibit reduction of 100mgL-1 NO3--N. The capability of simultaneous reduction of Cr(VI) and nitrate was illustrated by the reductase genes contained in the LZ-4 genome. Application in a batch membrane bioreactor showed that the immobilized strain LZ-4 could remove over 95% of 500mgL-1 NO3--N, 80% of 10mgL-1 Cr(VI), and 96% of 5000mgL-1 COD in each batch of 46days. In summary, the strain LZ-4 is an ideal candidate for remediation of co-contaminants.
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Affiliation(s)
- Xuan Yu
- Ministry of Education Key Laboratory of Cell Activities and Stress Adaptations, School of Life Science, Lanzhou University, Tianshuinanlu #222, Lanzhou, Gansu 730000, PR China; Gansu Academy of Membrane Science and Technology, Duanjiatanlu #1272, Lanzhou, Gansu 730020, PR China; School of Chemical Engineering and Technology, China University of Mining and Technology, Xuzhou, Jiangsu 221116, PR China
| | - Yiming Jiang
- Ministry of Education Key Laboratory of Cell Activities and Stress Adaptations, School of Life Science, Lanzhou University, Tianshuinanlu #222, Lanzhou, Gansu 730000, PR China
| | - Haiying Huang
- Ministry of Education Key Laboratory of Cell Activities and Stress Adaptations, School of Life Science, Lanzhou University, Tianshuinanlu #222, Lanzhou, Gansu 730000, PR China
| | - Juanjuan Shi
- Ministry of Education Key Laboratory of Cell Activities and Stress Adaptations, School of Life Science, Lanzhou University, Tianshuinanlu #222, Lanzhou, Gansu 730000, PR China
| | - Kejia Wu
- Ministry of Education Key Laboratory of Cell Activities and Stress Adaptations, School of Life Science, Lanzhou University, Tianshuinanlu #222, Lanzhou, Gansu 730000, PR China
| | - Pengyun Zhang
- Gansu Academy of Membrane Science and Technology, Duanjiatanlu #1272, Lanzhou, Gansu 730020, PR China
| | - Jianguo Lv
- Gansu Academy of Membrane Science and Technology, Duanjiatanlu #1272, Lanzhou, Gansu 730020, PR China
| | - Hongli Li
- PetroChina Lanzhou Petrochemical Company, Yumenjie #10, Lanzhou, Gansu 730060, PR China
| | - Huan He
- School of Chemical Engineering and Technology, China University of Mining and Technology, Xuzhou, Jiangsu 221116, PR China
| | - Pu Liu
- Ministry of Education Key Laboratory of Cell Activities and Stress Adaptations, School of Life Science, Lanzhou University, Tianshuinanlu #222, Lanzhou, Gansu 730000, PR China
| | - Xiangkai Li
- Ministry of Education Key Laboratory of Cell Activities and Stress Adaptations, School of Life Science, Lanzhou University, Tianshuinanlu #222, Lanzhou, Gansu 730000, PR China.
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Rehm FBH, Chen S, Rehm BHA. Enzyme Engineering for In Situ Immobilization. Molecules 2016; 21:E1370. [PMID: 27754434 PMCID: PMC6273058 DOI: 10.3390/molecules21101370] [Citation(s) in RCA: 66] [Impact Index Per Article: 8.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/30/2016] [Revised: 10/05/2016] [Accepted: 10/05/2016] [Indexed: 11/19/2022] Open
Abstract
Enzymes are used as biocatalysts in a vast range of industrial applications. Immobilization of enzymes to solid supports or their self-assembly into insoluble particles enhances their applicability by strongly improving properties such as stability in changing environments, re-usability and applicability in continuous biocatalytic processes. The possibility of co-immobilizing various functionally related enzymes involved in multistep synthesis, conversion or degradation reactions enables the design of multifunctional biocatalyst with enhanced performance compared to their soluble counterparts. This review provides a brief overview of up-to-date in vitro immobilization strategies while focusing on recent advances in enzyme engineering towards in situ self-assembly into insoluble particles. In situ self-assembly approaches include the bioengineering of bacteria to abundantly form enzymatically active inclusion bodies such as enzyme inclusions or enzyme-coated polyhydroxyalkanoate granules. These one-step production strategies for immobilized enzymes avoid prefabrication of the carrier as well as chemical cross-linking or attachment to a support material while the controlled oriented display strongly enhances the fraction of accessible catalytic sites and hence functional enzymes.
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Affiliation(s)
- Fabian B H Rehm
- Institute of Fundamental Sciences, Massey University, Private Bag 11222, Palmerston North 4442, New Zealand.
| | - Shuxiong Chen
- Institute of Fundamental Sciences, Massey University, Private Bag 11222, Palmerston North 4442, New Zealand.
| | - Bernd H A Rehm
- Institute of Fundamental Sciences, Massey University, Private Bag 11222, Palmerston North 4442, New Zealand.
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Gutiérrez-Corona JF, Romo-Rodríguez P, Santos-Escobar F, Espino-Saldaña AE, Hernández-Escoto H. Microbial interactions with chromium: basic biological processes and applications in environmental biotechnology. World J Microbiol Biotechnol 2016; 32:191. [DOI: 10.1007/s11274-016-2150-0] [Citation(s) in RCA: 44] [Impact Index Per Article: 5.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/30/2016] [Accepted: 09/25/2016] [Indexed: 12/18/2022]
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42
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Parlane NA, Gupta SK, Rubio-Reyes P, Chen S, Gonzalez-Miro M, Wedlock DN, Rehm BHA. Self-Assembled Protein-Coated Polyhydroxyalkanoate Beads: Properties and Biomedical Applications. ACS Biomater Sci Eng 2016; 3:3043-3057. [PMID: 33445349 DOI: 10.1021/acsbiomaterials.6b00355] [Citation(s) in RCA: 43] [Impact Index Per Article: 5.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/20/2022]
Abstract
Polyhydroxyalkanoates (PHAs) are biological polyesters that can be naturally produced by a range of bacteria as water-insoluble inclusions composed of a PHA core coated with PHA synthesis, structural, and regulatory proteins. These naturally self-assembling shell-core particles have been recently conceived as biomaterials that can be bioengineered as biologically active beads for medical applications. Protein engineering of PHA-associated proteins enabled the production of PHA-protein assemblies exhibiting biologically active protein-based functions relevant for applications as vaccines or diagnostics. Here we provide an overview of the recent advances in bioengineering of PHA particles toward the display of biomedically relevant protein functions such as selected disease-specific antigens as diagnostic tools or for the design of particulate subunit vaccines against infectious diseases such as tuberculosis, meningitis, pneumonia, and hepatitis C.
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Affiliation(s)
- Natalie A Parlane
- AgResearch, Hopkirk Research Institute, Palmerston North 4442, New Zealand
| | - Sandeep K Gupta
- AgResearch, Hopkirk Research Institute, Palmerston North 4442, New Zealand
| | - Patricia Rubio-Reyes
- Institute of Fundamental Sciences, Massey University, Private Bag 11222, Palmerston North 4442, New Zealand
| | - Shuxiong Chen
- Institute of Fundamental Sciences, Massey University, Private Bag 11222, Palmerston North 4442, New Zealand
| | - Majela Gonzalez-Miro
- Institute of Fundamental Sciences, Massey University, Private Bag 11222, Palmerston North 4442, New Zealand
| | - D Neil Wedlock
- AgResearch, Hopkirk Research Institute, Palmerston North 4442, New Zealand
| | - Bernd H A Rehm
- Institute of Fundamental Sciences, Massey University, Private Bag 11222, Palmerston North 4442, New Zealand.,MacDiarmid Institute for Advanced Materials and Nanotechnology, Kelburn Parade, Wellington 6140, New Zealand
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A comparative review towards potential of microbial cells for heavy metal removal with emphasis on biosorption and bioaccumulation. World J Microbiol Biotechnol 2016; 32:170. [DOI: 10.1007/s11274-016-2117-1] [Citation(s) in RCA: 61] [Impact Index Per Article: 7.6] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/03/2016] [Accepted: 07/25/2016] [Indexed: 10/21/2022]
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44
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The promises and challenges of fusion constructs in protein biochemistry and enzymology. Appl Microbiol Biotechnol 2016; 100:8273-81. [PMID: 27541749 DOI: 10.1007/s00253-016-7795-y] [Citation(s) in RCA: 27] [Impact Index Per Article: 3.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/26/2016] [Revised: 08/04/2016] [Accepted: 08/05/2016] [Indexed: 01/05/2023]
Abstract
Fusion constructs are used to improve the properties of or impart novel functionality to proteins for biotechnological applications. The biochemical characteristics of enzymes or functional proteins optimized by fusion include catalytic efficiency, stability, activity, expression, secretion, and solubility. In this review, we summarize the parameters of enzymes or functional proteins that can be modified by fusion constructs. For each parameter, fusion strategies and molecular partners are examined using examples from recent studies. Future prospects in this field are also discussed. This review is expected to increase interest in and advance fusion strategies for optimization of enzymes and other functional proteins.
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45
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Shi A, Zheng H, Yomano LP, York SW, Shanmugam KT, Ingram LO. Plasmidic Expression of nemA and yafC* Increased Resistance of Ethanologenic Escherichia coli LY180 to Nonvolatile Side Products from Dilute Acid Treatment of Sugarcane Bagasse and Artificial Hydrolysate. Appl Environ Microbiol 2016; 82:2137-2145. [PMID: 26826228 PMCID: PMC4807516 DOI: 10.1128/aem.03488-15] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/26/2015] [Accepted: 01/24/2016] [Indexed: 11/20/2022] Open
Abstract
Hydrolysate-resistant Escherichia coli SL100 was previously isolated from ethanologenic LY180 after sequential transfers in AM1 medium containing a dilute acid hydrolysate of sugarcane bagasse and was used as a source of resistance genes. Many genes that affect tolerance to furfural, the most abundant inhibitor, have been described previously. To identify genes associated with inhibitors other than furfural, plasmid clones were selected in an artificial hydrolysate that had been treated with a vacuum to remove furfural. Two new resistance genes were discovered from Sau3A1 libraries of SL100 genomic DNA: nemA (N-ethylmaleimide reductase) and a putative regulatory gene containing a mutation in the coding region, yafC*. The presence of these mutations in SL100 was confirmed by sequencing. A single mutation was found in the upstream regulatory region of nemR (nemRA operon) in SL100. This mutation increased nemA activity 20-fold over that of the parent organism (LY180) in AM1 medium without hydrolysate and increased nemA mRNA levels >200-fold. Addition of hydrolysates induced nemA expression (mRNA and activity), in agreement with transcriptional control. NemA activity was stable in cell extracts (9 h, 37°C), eliminating a role for proteinase in regulation. LY180 with a plasmid expressing nemA or yafC* was more resistant to a vacuum-treated sugarcane bagasse hydrolysate and to a vacuum-treated artificial hydrolysate than LY180 with an empty-vector control. Neither gene affected furfural tolerance. The vacuum-treated hydrolysates inhibited the reduction of N-ethylmaleimide by NemA while also serving as substrates. Expression of the nemA or yafC* plasmid in LY180 doubled the rate of ethanol production from the vacuum-treated sugarcane bagasse hydrolysate.
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Affiliation(s)
- Aiqin Shi
- Department of Microbiology and Cell Science, University of Florida, Gainesville, Florida, USA
| | - Huabao Zheng
- Department of Microbiology and Cell Science, University of Florida, Gainesville, Florida, USA
| | - Lorraine P Yomano
- Department of Microbiology and Cell Science, University of Florida, Gainesville, Florida, USA
| | - Sean W York
- Department of Microbiology and Cell Science, University of Florida, Gainesville, Florida, USA
| | - Keelnatham T Shanmugam
- Department of Microbiology and Cell Science, University of Florida, Gainesville, Florida, USA
| | - Lonnie O Ingram
- Department of Microbiology and Cell Science, University of Florida, Gainesville, Florida, USA
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46
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Promising applications of synthetic biology – and how to avoid their potential pitfalls. Synth Biol (Oxf) 2016. [DOI: 10.1007/978-3-658-10988-2_13] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/22/2022] Open
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47
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Nitroreductase gene-directed enzyme prodrug therapy: insights and advances toward clinical utility. Biochem J 2015; 471:131-53. [PMID: 26431849 DOI: 10.1042/bj20150650] [Citation(s) in RCA: 91] [Impact Index Per Article: 10.1] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/21/2022]
Abstract
This review examines the vast catalytic and therapeutic potential offered by type I (i.e. oxygen-insensitive) nitroreductase enzymes in partnership with nitroaromatic prodrugs, with particular focus on gene-directed enzyme prodrug therapy (GDEPT; a form of cancer gene therapy). Important first indications of this potential were demonstrated over 20 years ago, for the enzyme-prodrug pairing of Escherichia coli NfsB and CB1954 [5-(aziridin-1-yl)-2,4-dinitrobenzamide]. However, it has become apparent that both the enzyme and the prodrug in this prototypical pairing have limitations that have impeded their clinical progression. Recently, substantial advances have been made in the biodiscovery and engineering of superior nitroreductase variants, in particular development of elegant high-throughput screening capabilities to enable optimization of desirable activities via directed evolution. These advances in enzymology have been paralleled by advances in medicinal chemistry, leading to the development of second- and third-generation nitroaromatic prodrugs that offer substantial advantages over CB1954 for nitroreductase GDEPT, including greater dose-potency and enhanced ability of the activated metabolite(s) to exhibit a local bystander effect. In addition to forging substantial progress towards future clinical trials, this research is supporting other fields, most notably the development and improvement of targeted cellular ablation capabilities in small animal models, such as zebrafish, to enable cell-specific physiology or regeneration studies.
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Ge S, Ge S, Zhou M, Dong X. Bioremediation of hexavalent chromate using permeabilized Brevibacterium sp. and Stenotrophomonas sp. cells. JOURNAL OF ENVIRONMENTAL MANAGEMENT 2015; 157:54-59. [PMID: 25881152 DOI: 10.1016/j.jenvman.2015.04.011] [Citation(s) in RCA: 21] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 01/28/2015] [Revised: 04/04/2015] [Accepted: 04/07/2015] [Indexed: 06/04/2023]
Abstract
Bioremediation has been found to be a useful method for removing hexavalent chromium (Cr(VI)), which is very toxic, from wastewater. Two strains of bacteria that were able to reduce Cr(VI) effectively were isolated from Cr(VI) contaminated soil samples and identified as Brevibacterium sp. K1 and Stenotrophomonas sp. D6, respectively, based on 16S rRNA gene sequence analyses. Brevibacterium sp. K1 and Stenotrophomonas sp. D6 could grow in Luria-Broth medium containing K2Cr2O7 at 1000 and 1600 mg/L, respectively, and they completely reduced the Cr(VI) in LB medium containing K2Cr2O7 at 200 mg/L within 72 h. Further analyses revealed that permeabilized K1 and D6 cells reduced Cr(VI) more effectively than did the resting cells. Triton X-100 was the best permeabilizing agent that was tested. The permeabilized cells of both strains could completely reduce Cr(VI) in industrial wastewater twice before needing to be replenished. The results suggested that these chromate-reducing bacteria are potential candidates for practical use biotreating industrial effluents containing Cr(VI) with Stenotrophomonas sp. D6 being the more effective bacterium.
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Affiliation(s)
- Shimei Ge
- College of Life and Environmental Science, Wenzhou University, Wenzhou 325035, China; Key Laboratory for Subtropical Water Environment and Marine Biological Resources Protection, Wenzhou 325035, China.
| | - Shichao Ge
- Department of Research and Development, Shanghai Benegene Biotechnology Co., Ltd., Shanghai 201114, China
| | - Maohong Zhou
- College of Life and Environmental Science, Wenzhou University, Wenzhou 325035, China; Key Laboratory for Subtropical Water Environment and Marine Biological Resources Protection, Wenzhou 325035, China
| | - Xinjiao Dong
- College of Life and Environmental Science, Wenzhou University, Wenzhou 325035, China; Key Laboratory for Subtropical Water Environment and Marine Biological Resources Protection, Wenzhou 325035, China
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DENG PENG, TAN XIAOQING, WU YING, BAI QUNHUA, JIA YAN, XIAO HONG. Cloning and sequence analysis demonstrate the chromate reduction ability of a novel chromate reductase gene from Serratia sp. Exp Ther Med 2015; 9:795-800. [PMID: 25667630 PMCID: PMC4316894 DOI: 10.3892/etm.2014.2148] [Citation(s) in RCA: 19] [Impact Index Per Article: 2.1] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/14/2014] [Accepted: 10/09/2014] [Indexed: 11/10/2022] Open
Abstract
The ChrT gene encodes a chromate reductase enzyme which catalyzes the reduction of Cr(VI). The chromate reductase is also known as flavin mononucleotide (FMN) reductase (FMN_red). The aim of the present study was to clone the full-length ChrT DNA from Serratia sp. CQMUS2 and analyze the deduced amino acid sequence and three-dimensional structure. The putative ChrT gene fragment of Serratia sp. CQMUS2 was isolated by polymerase chain reaction (PCR), according to the known FMN_red gene sequence from Serratia sp. AS13. The flanking sequences of the ChrT gene were obtained by high efficiency TAIL-PCR, while the full-length gene of ChrT was cloned in Escherichia coli for subsequent sequencing. The nucleotide sequence of ChrT was submitted onto GenBank under the accession number, KF211434. Sequence analysis of the gene and amino acids was conducted using the Basic Local Alignment Search Tool, and open reading frame (ORF) analysis was performed using ORF Finder software. The ChrT gene was found to be an ORF of 567 bp that encodes a 188-amino acid enzyme with a calculated molecular weight of 20.4 kDa. In addition, the ChrT protein was hypothesized to be an NADPH-dependent FMN_red and a member of the flavodoxin-2 superfamily. The amino acid sequence of ChrT showed high sequence similarity to the FMN reductase genes of Klebsiella pneumonia and Raoultella ornithinolytica, which belong to the flavodoxin-2 superfamily. Furthermore, ChrT was shown to have a 85.6% similarity to the three-dimensional structure of Escherichia coli ChrR, sharing four common enzyme active sites for chromate reduction. Therefore, ChrT gene cloning and protein structure determination demonstrated the ability of the gene for chromate reduction. The results of the present study provide a basis for further studies on ChrT gene expression and protein function.
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Affiliation(s)
- PENG DENG
- Department of Occupational and Environmental Health, College of Public Health and Administration, Chongqing Medical University, Chongqing 400016, P.R. China
| | - XIAOQING TAN
- Physical Examination Center, Third People’s Hospital of Chongqing, Chongqing 401121, P.R. China
| | - YING WU
- Department of Occupational and Environmental Health, College of Public Health and Administration, Chongqing Medical University, Chongqing 400016, P.R. China
| | - QUNHUA BAI
- Department of Occupational and Environmental Health, College of Public Health and Administration, Chongqing Medical University, Chongqing 400016, P.R. China
| | - YAN JIA
- Department of Occupational and Environmental Health, College of Public Health and Administration, Chongqing Medical University, Chongqing 400016, P.R. China
| | - HONG XIAO
- Department of Occupational and Environmental Health, College of Public Health and Administration, Chongqing Medical University, Chongqing 400016, P.R. China
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