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He S, Fong K, Shi C, Shi X. Proteomic and mutagenic analyses for cross-protective mechanisms on ethanol adaptation to freezing stress in Salmonella Enteritidis. Food Control 2023. [DOI: 10.1016/j.foodcont.2022.109376] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/16/2022]
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2
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Doukyu N, Taguchi K. Involvement of catalase and superoxide dismutase in hydrophobic organic solvent tolerance of Escherichia coli. AMB Express 2021; 11:97. [PMID: 34189628 PMCID: PMC8241964 DOI: 10.1186/s13568-021-01258-w] [Citation(s) in RCA: 8] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/18/2021] [Accepted: 06/16/2021] [Indexed: 12/22/2022] Open
Abstract
Escherichia coli strains are generally sensitive to hydrophobic organic solvents such as n-hexane and cyclohexane. Oxidative stress in E. coli by exposure to these hydrophobic organic solvents has been poorly understood. In the present study, we examined organic solvent tolerance and oxygen radical generation in E. coli mutants deficient in reactive oxygen species (ROS)-scavenging enzymes. The organic solvent tolerances in single gene mutants lacking genes encoding superoxide dismutase (sodA, sodB, and sodC), catalase (katE and katG), and alkyl hydroperoxide reductase (ahpCF) were similar to that of parent strain BW25113. We constructed a BW25113-based katE katG double mutant (BW25113∆katE∆katG) and sodA sodB double mutant (BW25113sodA∆sodB). These double-gene mutants were more sensitive to hydrophobic organic solvents than BW25113. In addition, the intracellular ROS levels in E. coli strains increased by the addition of n-hexane or cyclohexane. The ROS levels in BW25113∆katE∆katG and BW25113∆sodA∆sodB induced by exposure to the solvents were higher than that in BW25113. These results suggested that ROS-scavenging enzymes contribute to the maintenance of organic solvent tolerance in E. coli. In addition, the promoter activities of sodA and sodB were significantly increased by exposure to n-hexane.
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Affiliation(s)
- Noriyuki Doukyu
- Department of Life Science, Toyo University, 1-1-1 Izumino, Itakura-machi, Gunma 374-0193 Japan
- Bio-Nano Electronic Research Center, Toyo University, 2100, Kujirai, Kawagoe, Saitama 350-8585 Japan
| | - Katsuya Taguchi
- Department of Life Science, Toyo University, 1-1-1 Izumino, Itakura-machi, Gunma 374-0193 Japan
- Bio-Nano Electronic Research Center, Toyo University, 2100, Kujirai, Kawagoe, Saitama 350-8585 Japan
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3
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Wang T, Tague N, Whelan SA, Dunlop MJ. Programmable gene regulation for metabolic engineering using decoy transcription factor binding sites. Nucleic Acids Res 2021; 49:1163-1172. [PMID: 33367820 PMCID: PMC7826281 DOI: 10.1093/nar/gkaa1234] [Citation(s) in RCA: 25] [Impact Index Per Article: 8.3] [Reference Citation Analysis] [Abstract] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/04/2020] [Revised: 11/12/2020] [Accepted: 12/08/2020] [Indexed: 12/30/2022] Open
Abstract
Transcription factor decoy binding sites are short DNA sequences that can titrate a transcription factor away from its natural binding site, therefore regulating gene expression. In this study, we harness synthetic transcription factor decoy systems to regulate gene expression for metabolic pathways in Escherichia coli. We show that transcription factor decoys can effectively regulate expression of native and heterologous genes. Tunability of the decoy can be engineered via changes in copy number or modifications to the DNA decoy site sequence. Using arginine biosynthesis as a showcase, we observed a 16-fold increase in arginine production when we introduced the decoy system to steer metabolic flux towards increased arginine biosynthesis, with negligible growth differences compared to the wild type strain. The decoy-based production strain retains high genetic integrity; in contrast to a gene knock-out approach where mutations were common, we detected no mutations in the production system using the decoy-based strain. We further show that transcription factor decoys are amenable to multiplexed library screening by demonstrating enhanced tolerance to pinene with a combinatorial decoy library. Our study shows that transcription factor decoy binding sites are a powerful and compact tool for metabolic engineering.
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Affiliation(s)
- Tiebin Wang
- Molecular Biology, Cell Biology & Biochemistry, Boston University, Boston, MA 02215, USA.,Biological Design Center, Boston University, Boston, MA 02215, USA
| | - Nathan Tague
- Biological Design Center, Boston University, Boston, MA 02215, USA.,Biomedical Engineering, Boston University, Boston, MA 02215, USA
| | | | - Mary J Dunlop
- Molecular Biology, Cell Biology & Biochemistry, Boston University, Boston, MA 02215, USA.,Biological Design Center, Boston University, Boston, MA 02215, USA.,Biomedical Engineering, Boston University, Boston, MA 02215, USA
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Kutyła M, Fiedurek J, Gromada A, Jędrzejewski K, Trytek M. Mutagenesis and Adaptation of the Psychrotrophic Fungus Chrysosporium pannorum A-1 as a Method for Improving β-pinene Bioconversion. Molecules 2020; 25:E2589. [PMID: 32498456 PMCID: PMC7321369 DOI: 10.3390/molecules25112589] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/12/2020] [Revised: 05/31/2020] [Accepted: 06/01/2020] [Indexed: 11/17/2022] Open
Abstract
Mutagenesis and adaptation of the psychrotrophic fungus Chrysosporium pannorum A-1 to the toxic substrate β-pinene were used to obtain a biocatalyst with increased resistance to this terpene and improved bioconversion properties. Mutants of the parental strain were induced with UV light and N-methyl-N'-nitro-N-nitrosoguanidine. Mutants resistant to β-pinene were isolated using agar plates with a linear gradient of substrate concentrations. Active mutants were selected based on their general metabolic activity (GMA) expressed as oxygen consumption rate. Compared to the parental strain, the most active mutant showed an enhanced biotransformation ability to convert β-pinene to trans-pinocarveol (315 mg per g of dry mycelium), a 4.3-fold greater biocatalytic activity, and a higher resistance to H2O2-induced oxidative stress. Biotransformation using adapted mutants yielded twice as much trans-pinocarveol as the reaction catalyzed by non-adapted mutants. The results indicate that mutagenesis and adaptation of C. pannorum A-1 is an effective method of enhancing β-bioconversion of terpenes.
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Affiliation(s)
| | | | | | | | - Mariusz Trytek
- Department of Industrial and Environmental Microbiology, Faculty of Biology and Biotechnology, Maria Curie-Skłodowska University, Akademicka 19, 20-033 Lublin, Poland; (M.K.); (J.F.); (A.G.); (K.J.)
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5
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Yoshimoto N, Kawai T, Yoshida M, Izawa S. Xylene causes oxidative stress and pronounced translation repression in Saccharomyces cerevisiae. J Biosci Bioeng 2019; 128:697-703. [DOI: 10.1016/j.jbiosc.2019.05.016] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/19/2019] [Revised: 05/20/2019] [Accepted: 05/30/2019] [Indexed: 12/23/2022]
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6
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Ethanol Adaptation Strategies in Salmonella enterica Serovar Enteritidis Revealed by Global Proteomic and Mutagenic Analyses. Appl Environ Microbiol 2019; 85:AEM.01107-19. [PMID: 31375481 DOI: 10.1128/aem.01107-19] [Citation(s) in RCA: 11] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/15/2019] [Accepted: 07/21/2019] [Indexed: 01/07/2023] Open
Abstract
Salmonella enterica subsp. enterica serovar Enteritidis is able to adapt to sublethal concentrations of ethanol, which subsequently induce tolerance of this pathogen to normally lethal ethanol challenges. This work aims to elucidate the underlying ethanol adaptation mechanisms of S Enteritidis by proteomic and mutagenic analyses. The global proteomic response of S Enteritidis to ethanol adaptation (5% ethanol for 1 h) was determined by isobaric tags for relative and absolute quantification (iTRAQ), and it was found that a total of 138 proteins were differentially expressed in ethanol-adapted cells compared to nonadapted cells. A total of 56 upregulated proteins were principally associated with purine metabolism and as transporters for glycine betaine, phosphate, d-alanine, thiamine, and heme, whereas 82 downregulated proteins were mainly involved in enterobactin biosynthesis and uptake, the ribosome, flagellar assembly, and virulence. Moreover, mutagenic analysis further revealed the functions of two highly upregulated proteins belonging to purine metabolism (HiuH, 5-hydroxyisourate hydrolase) and glycine betaine transport (ProX, glycine betaine-binding periplasmic protein) pathways. Deletion of either hiuH or proX resulted in the development of a stronger ethanol tolerance response, suggesting negative regulatory roles in ethanol adaptation. Collectively, this work suggests that S Enteritidis employs multiple strategies to coordinate ethanol adaptation.IMPORTANCE Stress adaptation in foodborne pathogens has been recognized as a food safety concern since it may compromise currently employed microbial intervention strategies. While adaptation to sublethal levels of ethanol is able to induce ethanol tolerance in foodborne pathogens, the molecular mechanism underlying this phenomenon is poorly characterized. Hence, global proteomic analysis and mutagenic analysis were conducted in the current work to understand the strategies employed by Salmonella enterica subsp. enterica serovar Enteritidis to respond to ethanol adaptation. It was revealed that coordinated regulation of multiple pathways involving metabolism, ABC transporters, regulators, enterobactin biosynthesis and uptake, the ribosome, flagellar assembly, and virulence was responsible for the development of ethanol adaptation response in this pathogen. Such knowledge will undoubtedly contribute to the development and implementation of more-effective food safety interventions.
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7
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Zhang Y, Dong R, Zhang M, Gao H. Native efflux pumps of Escherichia coli responsible for short and medium chain alcohol. Biochem Eng J 2018. [DOI: 10.1016/j.bej.2018.02.009] [Citation(s) in RCA: 13] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/16/2022]
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8
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Fiedurek J, Trytek M, Szczodrak J. Strain improvement of industrially important microorganisms based on resistance to toxic metabolites and abiotic stress. J Basic Microbiol 2017; 57:445-459. [DOI: 10.1002/jobm.201600710] [Citation(s) in RCA: 16] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/02/2016] [Accepted: 03/04/2017] [Indexed: 11/06/2022]
Affiliation(s)
- Jan Fiedurek
- Department of Industrial Microbiology; Institute of Microbiology and Biotechnology; Maria Curie-Skłodowska University; Lublin Poland
| | - Mariusz Trytek
- Department of Industrial Microbiology; Institute of Microbiology and Biotechnology; Maria Curie-Skłodowska University; Lublin Poland
| | - Janusz Szczodrak
- Department of Industrial Microbiology; Institute of Microbiology and Biotechnology; Maria Curie-Skłodowska University; Lublin Poland
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9
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Affiliation(s)
- Tao Jin
- Iowa State University; Department of Chemical and Biological Engineering; 2114 Sweeney Hall, 618 Bissell Rd. Ames, IA 50011 USA
| | - Jieni Lian
- Iowa State University; Department of Chemical and Biological Engineering; 2114 Sweeney Hall, 618 Bissell Rd. Ames, IA 50011 USA
| | - Laura R. Jarboe
- Iowa State University; Department of Chemical and Biological Engineering; 2114 Sweeney Hall, 618 Bissell Rd. Ames, IA 50011 USA
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Bernardi AC, Gai CS, Lu J, Sinskey AJ, Brigham CJ. Experimental evolution and gene knockout studies reveal AcrA-mediated isobutanol tolerance in Ralstonia eutropha. J Biosci Bioeng 2016; 122:64-9. [DOI: 10.1016/j.jbiosc.2015.12.015] [Citation(s) in RCA: 8] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/14/2015] [Revised: 12/02/2015] [Accepted: 12/18/2015] [Indexed: 12/12/2022]
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11
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Fu Y, Chen L, Zhang W. Regulatory mechanisms related to biofuel tolerance in producing microbes. J Appl Microbiol 2016; 121:320-32. [PMID: 27123568 DOI: 10.1111/jam.13162] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/03/2016] [Accepted: 04/20/2016] [Indexed: 11/28/2022]
Affiliation(s)
- Y. Fu
- Laboratory of Synthetic Microbiology; School of Chemical Engineering & Technology; Tianjin University; Tianjin China
- Key Laboratory of Systems Bioengineering (Ministry of Education); Tianjin University; Tianjin China
- SynBio Research Platform; Collaborative Innovation Center of Chemical Science and Engineering (Tianjin); Tianjin China
| | - L. Chen
- Laboratory of Synthetic Microbiology; School of Chemical Engineering & Technology; Tianjin University; Tianjin China
- Key Laboratory of Systems Bioengineering (Ministry of Education); Tianjin University; Tianjin China
- SynBio Research Platform; Collaborative Innovation Center of Chemical Science and Engineering (Tianjin); Tianjin China
| | - W. Zhang
- Laboratory of Synthetic Microbiology; School of Chemical Engineering & Technology; Tianjin University; Tianjin China
- Key Laboratory of Systems Bioengineering (Ministry of Education); Tianjin University; Tianjin China
- SynBio Research Platform; Collaborative Innovation Center of Chemical Science and Engineering (Tianjin); Tianjin China
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12
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Mi J, Schewe H, Buchhaupt M, Holtmann D, Schrader J. Efficient hydroxylation of 1,8-cineole with monoterpenoid-resistant recombinant Pseudomonas putida GS1. World J Microbiol Biotechnol 2016; 32:112. [PMID: 27263007 DOI: 10.1007/s11274-016-2071-y] [Citation(s) in RCA: 8] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/09/2016] [Accepted: 04/23/2016] [Indexed: 10/21/2022]
Abstract
In this work, monoterpenoid hydroxylation with Pseudomonas putida GS1 and KT2440 were investigated as host strains, and the cytochrome P450 monooxygenase CYP176A1 (P450cin) and its native redox partner cindoxin (CinC) from Citrobacter braakii were introduced in P. putida to catalyze the stereoselective hydroxylation of 1,8-cineole to (1R)-6β-hydroxy-1,8-cineole. Growth experiments in the presence of 1,8-cineole confirmed pseudomonads' superior resilience compared to E. coli. Whole-cell P. putida harboring P450cin with and without CinC were capable of hydroxylating 1,8-cineole, whereas coexpression of CinC has been shown to accelerate this bioconversion. Under the same conditions, P. putida GS1 produced more than twice the amount of heterologous P450cin and bioconversion product than P. putida KT2440. A concentration of 1.1 ± 0.1 g/L (1R)-6β-hydroxy-1,8-cineole was obtained within 55 h in shake flasks and 13.3 ± 1.9 g/L in 89 h in a bioreactor, the latter of which corresponds to a yield YP/S of 79 %. To the authors' knowledge, this is the highest product titer for a P450 based whole-cell monoterpene oxyfunctionalization reported so far. These results show that solvent-tolerant P. putida GS1 can be used as a highly efficient recombinant whole-cell biocatalyst for a P450 monooxygenase-based valorization of monoterpenoids.
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Affiliation(s)
- Jia Mi
- Biochemical Engineering, DECHEMA-Forschungsinstitut, Theodor-Heuss-Allee 25, 60486, Frankfurt, Germany
| | - Hendrik Schewe
- Biochemical Engineering, DECHEMA-Forschungsinstitut, Theodor-Heuss-Allee 25, 60486, Frankfurt, Germany
| | - Markus Buchhaupt
- Biochemical Engineering, DECHEMA-Forschungsinstitut, Theodor-Heuss-Allee 25, 60486, Frankfurt, Germany
| | - Dirk Holtmann
- Biochemical Engineering, DECHEMA-Forschungsinstitut, Theodor-Heuss-Allee 25, 60486, Frankfurt, Germany
| | - Jens Schrader
- Biochemical Engineering, DECHEMA-Forschungsinstitut, Theodor-Heuss-Allee 25, 60486, Frankfurt, Germany.
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Call TP, Akhtar MK, Baganz F, Grant C. Modulating the import of medium-chain alkanes in E. coli through tuned expression of FadL. J Biol Eng 2016; 10:5. [PMID: 27053948 PMCID: PMC4822313 DOI: 10.1186/s13036-016-0026-3] [Citation(s) in RCA: 13] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/23/2016] [Accepted: 03/29/2016] [Indexed: 01/13/2023] Open
Abstract
Background In recent years, there have been intensive efforts to develop synthetic microbial platforms for the production, biosensing and bio-remediation of fossil fuel constituents such as alkanes. Building predictable engineered systems for these applications will require the ability to tightly control and modulate the rate of import of alkanes into the host cell. The native components responsible for the import of alkanes within these systems have yet to be elucidated. To shed further insights on this, we used the AlkBGT alkane monooxygenase complex from Pseudomonas putida GPo1 as a reporter system for assessing alkane import in Escherichia coli. Two native E. coli transporters, FadL and OmpW, were evaluated for octane import given their proven functionality in the uptake of fatty acids along with their structural similarity to the P. putida GPo1 alkane importer, AlkL. Results Octane import was removed with deletion of fadL, but was restored by complementation with a fadL-encoding plasmid. Furthermore, tuned overexpression of FadL increased the rate of alkane import by up to 4.5- fold. A FadL deletion strain displayed a small but significant degree of tolerance toward hexane and octane relative to the wild type, while the responsiveness of the well-known alkane biosensor, AlkS, toward octane and decane was strongly reduced by 2.7- and 2.9-fold, respectively. Conclusions We unequivocally show for the first time that FadL serves as the major route for medium-chain alkane import in E. coli. The experimental approaches used within this study, which include an enzyme-based reporter system and a fluorescent alkane biosensor for quantification and real-time monitoring of alkane import, could be employed as part of an engineering toolkit for optimizing biological systems that depend on the uptake of alkanes. Thus, the findings will be particularly useful for biological applications such as bioremediation and biomanufacturing. Electronic supplementary material The online version of this article (doi:10.1186/s13036-016-0026-3) contains supplementary material, which is available to authorized users.
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Affiliation(s)
- Toby P Call
- Department of Biochemical Engineering, Advanced Centre for Biochemical Engineering, University College London, Torrington Place, London, WC1E 7JE UK ; Present address: Department of Biochemistry, University of Cambridge, 80 Tennis Court Road, Cambridge, CB2 1GA UK
| | - M Kalim Akhtar
- Department of Biochemical Engineering, Advanced Centre for Biochemical Engineering, University College London, Torrington Place, London, WC1E 7JE UK ; Present address: Institute of Molecular Plant Sciences, School of Biological Sciences, University of Edinburgh, Edinburgh, EH9 3BF UK
| | - Frank Baganz
- Department of Biochemical Engineering, Advanced Centre for Biochemical Engineering, University College London, Torrington Place, London, WC1E 7JE UK
| | - Chris Grant
- Department of Biochemical Engineering, Advanced Centre for Biochemical Engineering, University College London, Torrington Place, London, WC1E 7JE UK
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Si HM, Zhang F, Wu AN, Han RZ, Xu GC, Ni Y. DNA microarray of global transcription factor mutant reveals membrane-related proteins involved in n-butanol tolerance in Escherichia coli. BIOTECHNOLOGY FOR BIOFUELS 2016; 9:114. [PMID: 27252779 PMCID: PMC4888631 DOI: 10.1186/s13068-016-0527-9] [Citation(s) in RCA: 24] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 01/07/2016] [Accepted: 05/11/2016] [Indexed: 05/07/2023]
Abstract
BACKGROUND Escherichia coli has been explored as a platform host strain for biofuels production such as butanol. However, the severe toxicity of butanol is considered to be one major limitation for butanol production from E. coli. The goal of this study is therefore to construct butanol-tolerant E. coli strains and clarify the tolerance mechanisms. RESULTS A recombinant E. coli strain harboring σ(70) mutation capable of tolerating 2 % (v/v) butanol was isolated by the global transcription machinery engineering (gTME) approach. DNA microarrays were employed to assess the transcriptome profile of butanol-tolerant strain B8. Compared with the wild-type strain, 329 differentially expressed genes (197 up-regulated and 132 down-regulated) (p < 0.05; FC ≥ 2) were identified. These genes are involved in carbohydrate metabolism, energy metabolism, two-component signal transduction system, oxidative stress response, lipid and cell envelope biogenesis and efflux pump. CONCLUSIONS Several membrane-related proteins were proved to be involved in butanol tolerance of E. coli. Two down-regulated genes, yibT and yghW, were identified to be capable of affecting butanol tolerance by regulating membrane fatty acid composition. Another down-regulated gene ybjC encodes a predicted inner membrane protein. In addition, a number of up-regulated genes, such as gcl and glcF, contribute to supplement metabolic intermediates for glyoxylate and TCA cycles to enhance energy supply. Our results could serve as a practical strategy for the construction of platform E. coli strains as biofuel producer.
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Affiliation(s)
- Hai-Ming Si
- The Key Laboratory of Industrial Biotechnology, Ministry of Education, School of Biotechnology, Jiangnan University, Wuxi, 214122 Jiangsu China
| | - Fa Zhang
- The Key Laboratory of Industrial Biotechnology, Ministry of Education, School of Biotechnology, Jiangnan University, Wuxi, 214122 Jiangsu China
| | - An-Ning Wu
- The Key Laboratory of Industrial Biotechnology, Ministry of Education, School of Biotechnology, Jiangnan University, Wuxi, 214122 Jiangsu China
| | - Rui-Zhi Han
- The Key Laboratory of Industrial Biotechnology, Ministry of Education, School of Biotechnology, Jiangnan University, Wuxi, 214122 Jiangsu China
| | - Guo-Chao Xu
- The Key Laboratory of Industrial Biotechnology, Ministry of Education, School of Biotechnology, Jiangnan University, Wuxi, 214122 Jiangsu China
| | - Ye Ni
- The Key Laboratory of Industrial Biotechnology, Ministry of Education, School of Biotechnology, Jiangnan University, Wuxi, 214122 Jiangsu China
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Adaptation of the autotrophic acetogen Sporomusa ovata to methanol accelerates the conversion of CO2 to organic products. Sci Rep 2015; 5:16168. [PMID: 26530351 PMCID: PMC4632017 DOI: 10.1038/srep16168] [Citation(s) in RCA: 56] [Impact Index Per Article: 6.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/05/2015] [Accepted: 10/08/2015] [Indexed: 12/21/2022] Open
Abstract
Acetogens are efficient microbial catalysts for bioprocesses converting C1 compounds into organic products. Here, an adaptive laboratory evolution approach was implemented to adapt Sporomusa ovata for faster autotrophic metabolism and CO2 conversion to organic chemicals. S. ovata was first adapted to grow quicker autotrophically with methanol, a toxic C1 compound, as the sole substrate. Better growth on different concentrations of methanol and with H2-CO2 indicated the adapted strain had a more efficient autotrophic metabolism and a higher tolerance to solvent. The growth rate on methanol was increased 5-fold. Furthermore, acetate production rate from CO2 with an electrode serving as the electron donor was increased 6.5-fold confirming that the acceleration of the autotrophic metabolism of the adapted strain is independent of the electron donor provided. Whole-genome sequencing, transcriptomic, and biochemical studies revealed that the molecular mechanisms responsible for the novel characteristics of the adapted strain were associated with the methanol oxidation pathway and the Wood-Ljungdahl pathway of acetogens along with biosynthetic pathways, cell wall components, and protein chaperones. The results demonstrate that an efficient strategy to increase rates of CO2 conversion in bioprocesses like microbial electrosynthesis is to evolve the microbial catalyst by adaptive laboratory evolution to optimize its autotrophic metabolism.
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Mukhopadhyay A. Tolerance engineering in bacteria for the production of advanced biofuels and chemicals. Trends Microbiol 2015; 23:498-508. [DOI: 10.1016/j.tim.2015.04.008] [Citation(s) in RCA: 163] [Impact Index Per Article: 18.1] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/16/2015] [Revised: 04/17/2015] [Accepted: 04/23/2015] [Indexed: 02/06/2023]
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17
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Membrane transporter engineering in industrial biotechnology and whole cell biocatalysis. Trends Biotechnol 2015; 33:237-46. [DOI: 10.1016/j.tibtech.2015.02.001] [Citation(s) in RCA: 145] [Impact Index Per Article: 16.1] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/05/2014] [Revised: 01/15/2015] [Accepted: 02/02/2015] [Indexed: 02/06/2023]
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Overproduction of AcrR increases organic solvent tolerance mediated by modulation of SoxS regulon in Escherichia coli. Appl Microbiol Biotechnol 2014; 98:8763-73. [DOI: 10.1007/s00253-014-6024-9] [Citation(s) in RCA: 23] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/31/2014] [Revised: 08/06/2014] [Accepted: 08/07/2014] [Indexed: 11/30/2022]
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Watanabe R, Doukyu N. Improvement of organic solvent tolerance by disruption of the lon gene in Escherichia coli. J Biosci Bioeng 2014; 118:139-44. [PMID: 24571965 DOI: 10.1016/j.jbiosc.2014.01.011] [Citation(s) in RCA: 17] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/08/2013] [Revised: 12/20/2013] [Accepted: 01/21/2014] [Indexed: 11/25/2022]
Abstract
The Lon ATP-dependent protease plays an important role in regulating many biological processes in bacteria. In this study, we examined the organic solvent tolerance of a Δlon mutant of Escherichia coli K-12 and found that the mutant showed remarkably higher organic solvent tolerance than the parent strain. Δlon mutants are known to overproduce capsular polysaccharide, resulting in the formation of mucoid colonies. We considered that this increase in capsular polysaccharide production might be involved in the organic solvent tolerance in E. coli. However, a ΔlonΔwcaJ double-gene mutant displaying a nonmucoid phenotype was as tolerant to organic solvents as the Δlon mutant, suggesting that capsular polysaccharide is not involved in organic solvent tolerance. On the other hand, the Lon protease is known to exhibit proteolytic activity against the transcriptional activators MarA and SoxS, which can enhance the expression level of the AcrAB-TolC efflux pump. We found that the Δlon mutant showed a higher expression level of AcrB than the parent strain. In addition, the ΔlonΔacrB double-gene mutant showed a significant decrease in organic solvent tolerance. Thus, it was shown that organic solvent tolerance in the Δlon mutant depends on the AcrAB-TolC pump but not capsular polysaccharide. E. coli strain JA300 acrRIS marR overexpresses the AcrAB-TolC pump and exhibits high-level solvent tolerance. In an attempt to further improve the solvent tolerance of JA300 acrRIS marR, a lon gene disruptant of this strain was constructed. However, the resulting mutant JA300 acrRIS marR Δlon showed lower solvent tolerance than JA300 acrRIS marR.
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Affiliation(s)
- Rei Watanabe
- Graduate School of Interdisciplinary New Science, Toyo University, 2100 Kujirai, Kawagoe, Saitama 350-8585, Japan; Bio-Nano Electronic Research Center, Toyo University, 2100 Kujirai, Kawagoe, Saitama 350-8585, Japan
| | - Noriyuki Doukyu
- Graduate School of Interdisciplinary New Science, Toyo University, 2100 Kujirai, Kawagoe, Saitama 350-8585, Japan; Bio-Nano Electronic Research Center, Toyo University, 2100 Kujirai, Kawagoe, Saitama 350-8585, Japan; Department of Life Science, Toyo University, 1-1-1 Izumino, Itakura-machi, Gunma 374-0193, Japan.
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Engineering biofuel tolerance in non-native producing microorganisms. Biotechnol Adv 2014; 32:541-8. [PMID: 24530635 DOI: 10.1016/j.biotechadv.2014.02.001] [Citation(s) in RCA: 57] [Impact Index Per Article: 5.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/23/2013] [Revised: 01/19/2014] [Accepted: 02/08/2014] [Indexed: 01/17/2023]
Abstract
Large-scale production of renewable biofuels through microbiological processes has drawn significant attention in recent years, mostly due to the increasing concerns on the petroleum fuel shortages and the environmental consequences of the over-utilization of petroleum-based fuels. In addition to native biofuel-producing microbes that have been employed for biofuel production for decades, recent advances in metabolic engineering and synthetic biology have made it possible to produce biofuels in several non-native biofuel-producing microorganisms. Compared to native producers, these non-native systems carry the advantages of fast growth, simple nutrient requirements, readiness for genetic modifications, and even the capability to assimilate CO2 and solar energy, making them competitive alternative systems to further decrease the biofuel production cost. However, the tolerance of these non-native microorganisms to toxic biofuels is naturally low, which has restricted the potentials of their application for high-efficiency biofuel production. To address the issues, researches have been recently conducted to explore the biofuel tolerance mechanisms and to construct robust high-tolerance strains for non-native biofuel-producing microorganisms. In this review, we critically summarize the recent progress in this area, focusing on three popular non-native biofuel-producing systems, i.e. Escherichia coli, Lactobacillus and photosynthetic cyanobacteria.
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Chong H, Geng H, Zhang H, Song H, Huang L, Jiang R. EnhancingE. coliisobutanol tolerance through engineering its global transcription factor cAMP receptor protein (CRP). Biotechnol Bioeng 2013; 111:700-8. [DOI: 10.1002/bit.25134] [Citation(s) in RCA: 37] [Impact Index Per Article: 3.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/15/2013] [Revised: 09/16/2013] [Accepted: 10/10/2013] [Indexed: 11/11/2022]
Affiliation(s)
- Huiqing Chong
- School of Chemical & Biomedical Engineering; Nanyang Technological University; 62 Nanyang Drive Singapore 637459 Singapore
| | - Hefang Geng
- School of Chemical & Biomedical Engineering; Nanyang Technological University; 62 Nanyang Drive Singapore 637459 Singapore
| | - Hongfang Zhang
- School of Chemical & Biomedical Engineering; Nanyang Technological University; 62 Nanyang Drive Singapore 637459 Singapore
| | - Hao Song
- School of Chemical & Biomedical Engineering; Nanyang Technological University; 62 Nanyang Drive Singapore 637459 Singapore
| | - Lei Huang
- Institute of Biological Engineering, Department of Chemical and Biological Engineering; Zhejiang University; Hangzhou Zhejiang P. R. China
| | - Rongrong Jiang
- School of Chemical & Biomedical Engineering; Nanyang Technological University; 62 Nanyang Drive Singapore 637459 Singapore
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Watanabe R, Doukyu N. Contributions of mutations in acrR and marR genes to organic solvent tolerance in Escherichia coli. AMB Express 2012; 2:58. [PMID: 23148659 PMCID: PMC3514110 DOI: 10.1186/2191-0855-2-58] [Citation(s) in RCA: 27] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/02/2012] [Accepted: 11/07/2012] [Indexed: 12/02/2022] Open
Abstract
The AcrAB-TolC efflux pump is involved in maintaining intrinsic organic solvent tolerance in Escherichia coli. Mutations in regulatory genes such as marR, soxR, and acrR are known to increase the expression level of the AcrAB-TolC pump. To identify these mutations in organic solvent tolerant E. coli, eight cyclohexane-tolerant E. coli JA300 mutants were isolated and examined by DNA sequencing for mutations in marR, soxR, and acrR. Every mutant carried a mutation in either marR or acrR. Among all mutants, strain CH7 carrying a nonsense mutation in marR (named marR109) and an insertion of IS5 in acrR, exhibited the highest organic solvent-tolerance levels. To clarify the involvement of these mutations in improving organic solvent tolerance, they were introduced into the E. coli JA300 chromosome by site-directed mutagenesis using λ red-mediated homologous recombination. Consequently, JA300 mutants carrying acrR::IS5, marR109, or both were constructed and named JA300 acrRIS, JA300 marR, or JA300 acrRIS marR, respectively. The organic solvent tolerance levels of these mutants were increased in the following order: JA300 < JA300 acrRIS < JA300 marR < JA300 acrRIS marR. JA300 acrRIS marR formed colonies on an agar plate overlaid with cyclohexane and p-xylene (6:4 vol/vol mixture). The organic solvent-tolerance level and AcrAB-TolC efflux pump-expression level in JA300 acrRIS marR were similar to those in CH7. Thus, it was shown that the synergistic effects of mutations in only two regulatory genes, acrR and marR, can significantly increase organic solvent tolerance in E. coli.
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Liu J, Chen L, Wang J, Qiao J, Zhang W. Proteomic analysis reveals resistance mechanism against biofuel hexane in Synechocystis sp. PCC 6803. BIOTECHNOLOGY FOR BIOFUELS 2012; 5:68. [PMID: 22958739 PMCID: PMC3479031 DOI: 10.1186/1754-6834-5-68] [Citation(s) in RCA: 52] [Impact Index Per Article: 4.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 07/28/2012] [Accepted: 08/30/2012] [Indexed: 05/19/2023]
Abstract
BACKGROUND Recent studies have demonstrated that photosynthetic cyanobacteria could be an excellent cell factory to produce renewable biofuels and chemicals due to their capability to utilize solar energy and CO2 as the sole energy and carbon sources. Biosynthesis of carbon-neutral biofuel alkanes with good chemical and physical properties has been proposed. However, to make the process economically feasible, one major hurdle to improve the low cell tolerance to alkanes needed to be overcome. RESULTS Towards the goal to develop robust and high-alkane-tolerant hosts, in this study, the responses of model cyanobacterial Synechocystis PCC 6803 to hexane, a representative of alkane, were investigated using a quantitative proteomics approach with iTRAQ - LC-MS/MS technologies. In total, 1,492 unique proteins were identified, representing about 42% of all predicted protein in the Synechocystis genome. Among all proteins identified, a total of 164 and 77 proteins were found up- and down-regulated, respectively. Functional annotation and KEGG pathway enrichment analyses showed that common stress responses were induced by hexane in Synechocystis. Notably, a large number of transporters and membrane-bound proteins, proteins against oxidative stress and proteins related to sulfur relay system and photosynthesis were induced, suggesting that they are possibly the major protection mechanisms against hexane toxicity. CONCLUSION The study provided the first comprehensive view of the complicated molecular mechanism employed by cyanobacterial model species, Synechocystis to defend against hexane stress. The study also provided a list of potential targets to engineer Synechocystis against hexane stress.
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Affiliation(s)
- Jie Liu
- School of Chemical Engineering & Technology, Tianjin University, Tianjin 300072, P.R. China
- Key Laboratory of Systems Bioengineering, Ministry of Education of China, Tianjin 300072, P.R. China
| | - Lei Chen
- School of Chemical Engineering & Technology, Tianjin University, Tianjin 300072, P.R. China
- Key Laboratory of Systems Bioengineering, Ministry of Education of China, Tianjin 300072, P.R. China
| | - Jiangxin Wang
- School of Chemical Engineering & Technology, Tianjin University, Tianjin 300072, P.R. China
- Key Laboratory of Systems Bioengineering, Ministry of Education of China, Tianjin 300072, P.R. China
| | - Jianjun Qiao
- School of Chemical Engineering & Technology, Tianjin University, Tianjin 300072, P.R. China
- Key Laboratory of Systems Bioengineering, Ministry of Education of China, Tianjin 300072, P.R. China
| | - Weiwen Zhang
- School of Chemical Engineering & Technology, Tianjin University, Tianjin 300072, P.R. China
- Key Laboratory of Systems Bioengineering, Ministry of Education of China, Tianjin 300072, P.R. China
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