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Kumar R, Barbhuiya RI, Bohra V, Wong JWC, Singh A, Kaur G. Sustainable rhamnolipids production in the next decade - Advancing with Burkholderia thailandensis as a potent biocatalytic strain. Microbiol Res 2023; 272:127386. [PMID: 37094547 DOI: 10.1016/j.micres.2023.127386] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/02/2022] [Revised: 03/27/2023] [Accepted: 04/10/2023] [Indexed: 04/26/2023]
Abstract
Rhamnolipids are one of the most promising eco-friendly green glycolipids for bio-replacements of commercially available fossil fuel-based surfactants. However, the current industrial biotechnology practices cannot meet the required standards due to the low production yields, expensive biomass feedstocks, complicated processing, and opportunistic pathogenic nature of the conventional rhamnolipid producer strains. To overcome these problems, it has become important to realize non-pathogenic producer substitutes and high-yielding strategies supporting biomass-based production. We hereby review the inherent characteristics of Burkholderia thailandensis E264 which favor its competence towards such sustainable rhamnolipid biosynthesis. The underlying biosynthetic networks of this species have unveiled unique substrate specificity, carbon flux control and rhamnolipid congener profile. Acknowledging such desirable traits, the present review provides critical insights towards metabolism, regulation, upscaling, and applications of B. thailandensis rhamnolipids. Identification of their unique and naturally inducible physiology has proved to be beneficial for achieving previously unmet redox balance and metabolic flux requirements in rhamnolipids production. These developments in part are targeted by the strategic optimization of B. thailandensis valorizing low-cost substrates ranging from agro-industrial byproducts to next generation (waste) fractions. Accordingly, safer bioconversions can propel the industrial rhamnolipids in advanced biorefinery domains to promote circular economy, reduce carbon footprint and increased applicability as both social and environment friendly bioproducts.
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Affiliation(s)
- Rajat Kumar
- Department of Biology, Hong Kong Baptist University, Kowloon Tong, Hong Kong
| | | | - Varsha Bohra
- Department of Biology, Hong Kong Baptist University, Kowloon Tong, Hong Kong
| | - Jonathan W C Wong
- Department of Biology, Hong Kong Baptist University, Kowloon Tong, Hong Kong; Institute of Bioresources and Agriculture and Sino-Forest Applied Research Centre for Pearl River Delta Environment, Hong Kong Baptist University, Kowloon Tong, Hong Kong
| | - Ashutosh Singh
- School of Engineering, University of Guelph, Guelph, ON N1G2W1, Canada
| | - Guneet Kaur
- School of Engineering, University of Guelph, Guelph, ON N1G2W1, Canada.
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Ankulkar R, Chavan S, Aphale D, Chavan M, Mirza Y. Cytotoxicity of di-rhamnolipids produced by Pseudomonas aeruginosa RA5 against human cancerous cell lines. 3 Biotech 2022; 12:323. [PMID: 36276467 PMCID: PMC9568642 DOI: 10.1007/s13205-022-03391-0] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/03/2022] [Accepted: 09/30/2022] [Indexed: 11/01/2022] Open
Abstract
Rhamnolipid biosurfactant produced by Pseudomonas aeruginosa, possesses non-toxicity, environmental compatibility, a wide range of pH (4-8), temperature (4-100 °C), and salinity (1-10%) stability. The application of RLs is worldwide accepted in the pharmaceutical, medicinal, and food industries. It has been used for cytotoxicity efficacy analysis with a limited number of cancerous cell lines. To widen the scope of rhamnolipid application as an anticancer agent, we have studied Di-RLs homolog, 'Rha-Rha-C10-C10' produced by Pseudomonas aeruginosa RA5 against human cancerous cell lines including breast cancer (MCF-7), leukemia (K-562), cervical cancer (HeLa), Lung cancer (HOP-62), and colon cancer (HT-29) in a dose-dependent way. It was purified with silica gel chromatography followed by TLC and mass spectroscopy prior to cytotoxicity analysis. With a tensiometer, critical micelle concentration of Di-RLs was estimated to be 33.92 ± 2 mN/m at 0.2%. Cytotoxicity analysis of Di-RLs on K-562 cell line demonstrated inhibition with GI50 and TGI at < 10 µg/mL and 66.6 µg/mL, after 48 h of application. The morphology of human cancerous cell lines was observed under a laser confocal microscope with the SRB staining method. Further research is recommended to comprehend the Di-RLs as a potential anti-cancer agent.
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Affiliation(s)
- Rutuja Ankulkar
- Praj-Matrix - R&D Centre (Division of Praj Industries Limited), 402/403/1098, Urawade, Pirangut, Mulshi, Pune, Maharashtra 412 115 India
- Department of Microbiology, Walchand College of Arts and Science, District: Solapur, Solapur, 413006 India
| | - Sambhaji Chavan
- Praj-Matrix - R&D Centre (Division of Praj Industries Limited), 402/403/1098, Urawade, Pirangut, Mulshi, Pune, Maharashtra 412 115 India
| | - Durgadevi Aphale
- Praj-Matrix - R&D Centre (Division of Praj Industries Limited), 402/403/1098, Urawade, Pirangut, Mulshi, Pune, Maharashtra 412 115 India
| | - Meera Chavan
- Department of Microbiology, Walchand College of Arts and Science, District: Solapur, Solapur, 413006 India
| | - Yasmin Mirza
- Praj-Matrix - R&D Centre (Division of Praj Industries Limited), 402/403/1098, Urawade, Pirangut, Mulshi, Pune, Maharashtra 412 115 India
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Jiang L, Zhou H, Qin H, Zheng G, Atakpa EO, Lin X, Lin Y, Zhang C. Rhamnolipids produced under aerobic/anaerobic conditions: Comparative analysis and their promising applications. Sci Total Environ 2022; 811:152414. [PMID: 34923009 DOI: 10.1016/j.scitotenv.2021.152414] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 10/03/2021] [Revised: 11/24/2021] [Accepted: 12/10/2021] [Indexed: 06/14/2023]
Abstract
This research comprises a comparative study of the properties, rhl genes expression, and structural difference in rhamnolipids produced under different oxygen conditions via Pseudomonas sp. CH1. The critical micelle concentration (CMC) of rhamnolipids produced under aerobic conditions (RAO) was 100 mg/L. In contrast, rhamnolipids produced under anaerobic conditions (RNO) had a low CMC of 40 mg/L. RNO comprised six rhamnolipids homologs, and the proportion of mono-rhamnolipids was up to 87.83%; meanwhile, the percent ratio of di-rhamnolipids and mono-rhamnolipids in RAO was 63.1:36.9. Additionally, diversified applications for solubilization of hydrophobic pollutants and reduction in heavy oil viscosity were investigated. The addition of RNO greatly enhanced the solubility of phenanthrene in water, from 1.29 mg/L to 193.14 mg/L, a 148.7-fold increase. Moreover, the viscosity of heavy oil decreased by over 90% for both kinds of rhamnolipids, whereas RAO effectively reduced the viscosity even at a low temperature (10 °C). The findings of this study provide insights into the versatile potential applications of rhamnolipids produced under different oxygen conditions.
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Affiliation(s)
- Lijia Jiang
- Institute of Marine Biology, Ocean College, Zhejiang University, Zhoushan 316021, Zhejiang, China
| | - Hanghai Zhou
- Institute of Marine Biology, Ocean College, Zhejiang University, Zhoushan 316021, Zhejiang, China
| | - Huaitao Qin
- Institute of Ocean Engineering and Technology, Zhejiang University, Zhoushan 316021, Zhejiang, China
| | - Gang Zheng
- Ocean Research Center of Zhoushan, Zhejiang University, Zhoushan 316021, Zhejiang, China.
| | - Edidiong Okokon Atakpa
- Institute of Marine Biology, Ocean College, Zhejiang University, Zhoushan 316021, Zhejiang, China
| | - Xiaoyun Lin
- Institute of Marine Biology, Ocean College, Zhejiang University, Zhoushan 316021, Zhejiang, China
| | - Yuan Lin
- Institute of Ocean Engineering and Technology, Zhejiang University, Zhoushan 316021, Zhejiang, China
| | - Chunfang Zhang
- Institute of Marine Biology, Ocean College, Zhejiang University, Zhoushan 316021, Zhejiang, China.
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Phulpoto IA, Wang Y, Qazi MA, Hu B, Ndayisenga F, Yu Z. Bioprospecting of rhamnolipids production and optimization by an oil-degrading Pseudomonas sp. S2WE isolated from freshwater lake. Bioresour Technol 2021; 323:124601. [PMID: 33385627 DOI: 10.1016/j.biortech.2020.124601] [Citation(s) in RCA: 10] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 10/13/2020] [Revised: 12/18/2020] [Accepted: 12/19/2020] [Indexed: 06/12/2023]
Abstract
The present study revealed biosurfactants production by a novel oil-degrading Pseudomonas sp. S2WE isolated from hydrocarbon enriched water sample, where the genus Pseudomonas (48.65%) was dominated amongst several other genera. Biosurfactants produced by this strain showed the great potential for surface tension reduction (SFT) and emulsification. The extracted crude biosurfactants were characterized using ultra-high-performance liquid chromatography-Mass Spectrometry (UHPLC-MS) and identified various mono-and di-rhamnolipids homologs from the mixture. Moreover, the lowest SFT 33.05 ± 0.1 mN/m and highest emulsification of 60.65 ± 0.64% were achieved from rhamnolipids produced from glycerol with urea. Compared to initial screening, almost (>87%) higher emulsification was observed. In addition, the biosurfactants were found highly stable at different environmental factors i.e. temperature (4 °C-121 °C), pH (3-10) and NaCl conc. (1-9%). The high stable rhamnolipids produced by new Pseudomonas sp. S2WE in this study could widely be used in enormous industrial as well as environmental applications.
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Affiliation(s)
- Irfan Ali Phulpoto
- College of Resources and Environment, University of Chinese Academy of Sciences, 19 A Yuquan Road, Beijing 100049, PR China
| | - Yanfen Wang
- Yanshan Earth Critical Zone and Surface Fluxes Research Station, Chinese Academy of Sciences, No. 380 Huaibei Town, Huairou District, Beijing 101408, PR China
| | - Muneer Ahmed Qazi
- Institute of Microbiology, Faculty of Natural Science, Shah Abdul Latif University, Khairpur Mir's 66020, Sindh, Pakistan
| | - Bowen Hu
- College of Resources and Environment, University of Chinese Academy of Sciences, 19 A Yuquan Road, Beijing 100049, PR China
| | - Fabrice Ndayisenga
- College of Resources and Environment, University of Chinese Academy of Sciences, 19 A Yuquan Road, Beijing 100049, PR China
| | - Zhisheng Yu
- College of Resources and Environment, University of Chinese Academy of Sciences, 19 A Yuquan Road, Beijing 100049, PR China; RCEES-IMCAS-UCAS Joint-Lab of Microbial Technology for Environmental Science, Beijing 100085, China.
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El-Housseiny GS, Aboshanab KM, Aboulwafa MM, Hassouna NA. Structural and Physicochemical Characterization of Rhamnolipids produced by Pseudomonas aeruginosa P6. AMB Express 2020; 10:201. [PMID: 33146788 PMCID: PMC7642061 DOI: 10.1186/s13568-020-01141-0] [Citation(s) in RCA: 12] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/20/2020] [Accepted: 10/27/2020] [Indexed: 11/10/2022] Open
Abstract
Rhamnolipids are important biosurfactants for application in bioremediation, enhanced oil recovery, pharmaceutical, and detergent industry. In this study, rhamnolipids extracted from P. aeruginosa P6 were characterized to determine their potential fields of application. Thin-layer chromatographic analysis of the produced rhamnolipids indicated the production of two homologues: mono- and di-rhamnolipids, whose structures were verified by 1H and 13C nuclear magnetic resonance spectroscopy. Additionally, high performance liquid chromatography-mass spectrometry identified seven different rhamnolipid congeners, of which a significantly high proportion was di-rhamnolipids reaching 80.16%. Rha-Rha-C10-C10 was confirmed as the principal compound of the rhamnolipid mixture (24.30%). The rhamnolipids were capable of lowering surface tension of water to 36 mN/m at a critical micelle concentration of 0.2 g/L, and exhibited a great emulsifying activity (E24 = 63%). In addition, they showed excellent stability at pH ranges 4-8, NaCl concentrations up to 9% (w/v) and temperatures ranging from 20 to 100 °C and even after autoclaving. These results suggest that rhamnolipids, produced by P. aeruginosa P6 using the cheap substrate glycerol, are propitious for biotechnology use in extreme and complex environments, like oil reservoirs and hydrocarbon contaminated soil. Moreover, P. aeruginosa P6 may be considered, in its wild type form, as a promising industrial producer of di-RLs, which have superior characteristics for potential applications and offer outstanding commercial benefits.
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Affiliation(s)
- Ghadir S. El-Housseiny
- Department of Microbiology and Immunology, Faculty of Pharmacy, Organization of African Unity St, Ain shams University, POB: 11566, Abbassia, Cairo, Egypt
| | - Khaled M. Aboshanab
- Department of Microbiology and Immunology, Faculty of Pharmacy, Organization of African Unity St, Ain shams University, POB: 11566, Abbassia, Cairo, Egypt
| | - Mohammad M. Aboulwafa
- Department of Microbiology and Immunology, Faculty of Pharmacy, Organization of African Unity St, Ain shams University, POB: 11566, Abbassia, Cairo, Egypt
- Faculty of Pharmacy, King Salman International University, Ras-Sedr, South Sinai Egypt
| | - Nadia A. Hassouna
- Department of Microbiology and Immunology, Faculty of Pharmacy, Organization of African Unity St, Ain shams University, POB: 11566, Abbassia, Cairo, Egypt
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Akbar N, Siddiqui R, Iqbal M, Khan NA. Antibacterial Activities of Selected Pure Compounds Isolated from Gut Bacteria of Animals Living in Polluted Environments. Antibiotics (Basel) 2020; 9:E190. [PMID: 32316471 DOI: 10.3390/antibiotics9040190] [Citation(s) in RCA: 11] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [What about the content of this article? (0)] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/08/2020] [Revised: 04/04/2020] [Accepted: 04/07/2020] [Indexed: 01/16/2023] Open
Abstract
Antibiotic resistance is a global threat to public health, further accelerated by the misuse of antibiotics in humans and animals. Our recent studies have shown that gut bacteria of animals living in polluted environments are a potential source of antibacterials. Gut bacteria of cockroaches, water monitor lizards and the turtle exhibited molecules such as curcumenol, docosanedioic acid, N-acyl-homoserine lactone, L-homotyrosine and Di-rhamnolipids. Using purified compounds, assays were performed to determine their antibacterial properties using serial dilution method, cytotoxic effects using lactate dehydrogenase release, and cell viability using MTT assay. The results revealed that the purified compounds exhibited significant antibacterial activities (p < 0.05) against selected Gram-negative (Pseudomonas aeruginosa) and Gram-positive bacteria (Streptococcus pyogenes) with effective MIC50 and MIC90 at µg concentrations, and with minimal effects on human cells as observed from LDH and MTT assays. These findings are significant and provide a basis for the rational development of therapeutic antibacterials. Future studies are needed to determine in vivo effects of the identified molecules together with their mode of action, which could lead to the development of novel antibacterial(s).
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Abstract
Background Rhamnolipids are the most extensively studied biosurfactants and has been successfully used in various areas from bioremediation to industrial fields. Rhamnolipids structural composition decide their physicochemical properties. Different physicochemical properties influence their application potential. Rhamnolipids can be produced at both aerobic conditions and anaerobic conditions by Pseudomonas aeruginosa. This study aims to evaluate the oxygen effects on the rhamnolipids yield, structural composition, physicochemical properties and the rhl-genes expression in P. aeruginosa SG. Results will guide researchers to regulate microbial cells to synthesize rhamnolipids with different activity according to diverse application requirements. Results Quantitative real-time PCR analysis revealed that rhlAB genes were down-regulated under anaerobic conditions. Therefore, strain P. aeruginosa SG anaerobically produced less rhamnolipids (0.68 g/L) than that (11.65 g/L) under aerobic conditions when grown in media containing glycerol and nitrate. HPLC–MS analysis showed that aerobically produced rhamnolipids mainly contained Rha-C8-C10, Rha–Rha-C10-C12:1 and Rha–Rha-C8-C10; anaerobically produced rhamnolipids mainly contained Rha-C10-C12 and Rha-C10-C10. Anaerobically produced rhamnolipids contained more mono-rhamnolipids (94.7%) than that (54.8%) in aerobically produced rhamnolipids. rhlC gene was also down-regulated under anaerobic conditions, catalyzing less mono-rhamnolipids to form di-rhamnolipids. Aerobically produced rhamnolipids decreased air–water surface tension (ST) from 72.2 to 27.9 mN/m with critical micelle concentration (CMC) of 60 mg/L; anaerobically produced rhamnolipids reduced ST to 33.1 mN/m with CMC of 80 mg/L. Anaerobically produced rhamnolipids emulsified crude oil with EI24 = 80.3%, and aerobically produced rhamnolipids emulsified crude oil with EI24 = 62.3%. Both two rhamnolipids products retained surface activity (ST < 35.0 mN/m) and emulsifying activity (EI24 > 60.0%) under temperatures (4–121 °C), pH values (4–10) and NaCl concentrations less than 90 g/L. Conclusions Oxygen affected the rhl-genes expression in P. aeruginosa, thus altering the rhamnolipids yield, structural composition and physicochemical properties. Rhamnolipids produced at aerobic or anaerobic conditions was structurally distinct. Two rhamnolipids products had different application potential in diverse biotechnologies. Although both rhamnolipids products were thermo-stable and halo-tolerant, aerobically produced rhamnolipids possessed better surface activity, implying its well wetting activity and desorption property; anaerobically produced rhamnolipids exhibited better emulsifying activity, indicating its applicability for enhanced oil recovery and bioremediation of petroleum pollution.
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Affiliation(s)
- Feng Zhao
- CAS Key Laboratory of Pollution Ecology and Environmental Engineering, Institute of Applied Ecology, Chinese Academy of Sciences (CAS), Shenyang, 110016, Liaoning, China.
| | - Rongjiu Shi
- CAS Key Laboratory of Pollution Ecology and Environmental Engineering, Institute of Applied Ecology, Chinese Academy of Sciences (CAS), Shenyang, 110016, Liaoning, China
| | - Fang Ma
- State Key Laboratory of Urban Water Resource and Environment, Harbin Institute of Technology, Harbin, 150090, China
| | - Siqin Han
- CAS Key Laboratory of Pollution Ecology and Environmental Engineering, Institute of Applied Ecology, Chinese Academy of Sciences (CAS), Shenyang, 110016, Liaoning, China
| | - Ying Zhang
- CAS Key Laboratory of Pollution Ecology and Environmental Engineering, Institute of Applied Ecology, Chinese Academy of Sciences (CAS), Shenyang, 110016, Liaoning, China.
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Funston SJ, Tsaousi K, Rudden M, Smyth TJ, Stevenson PS, Marchant R, Banat IM. Characterising rhamnolipid production in Burkholderia thailandensis E264, a non-pathogenic producer. Appl Microbiol Biotechnol 2016; 100:7945-56. [PMID: 27147528 DOI: 10.1007/s00253-016-7564-y] [Citation(s) in RCA: 42] [Impact Index Per Article: 5.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/08/2016] [Accepted: 04/15/2016] [Indexed: 11/30/2022]
Abstract
Burkholderia thailandensis E264 is a rhamnolipid (RL)-producing gram-negative bacterium first isolated from the soils and stagnant waters of central and north-eastern Thailand. Growth of B. thailandensis E264 under two different incubation temperatures (25 and 30 °C) resulted in a significantly higher dry cell biomass production at 30 °C (7.71 g/l) than at 25 °C (4.75 g/l) after 264 h; however, incubation at the lower temperature resulted in consistently higher concentration of RL production throughout the growth period. After 264 h, the concentration of crude RL extract for the 25 °C culture was 2.79 g/l compared to 1.99 g/l for the 30 °C culture. Overall RL production concentration after 264 h was 0.258 g/g dry cell biomass (DCB) for the 30 °C culture compared to 0.587 g/g DCB for the 25 °C culture. Real-time PCR (qPCR) was also used to analyse expression of the RL biosynthesis genes throughout the incubation period at 25 °C showing that the expression of the rhlA, rhlB and rhlC genes is continuous. During the log and early stationary phases of growth, expression levels remain low and are increased upon entry to the late stationary phase. B. thailandensis E264 produces mostly di-RLs and the Di-RL C14-C14 in most abundance (41.88 %). Fermentations were also carried out in small-scale bioreactors (4 l working volume) under controlled conditions, and results showed that RL production was maintained. Our findings show that B. thailandensis E264 has excellent potential for industrial scale RL production.
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