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He Q, Zheng Y, Yan K, Tang J, Yang F, Tian Y, Yang L, Dou B, Chen Y, Gu J, Chen H, Yuan F, Bei W. The cAMP receptor protein gene contributes to growth, stress resistance, and colonization of Actinobacillus pleuropneumoniae. Vet Microbiol 2024; 290:110006. [PMID: 38308931 DOI: 10.1016/j.vetmic.2024.110006] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/11/2023] [Revised: 01/15/2024] [Accepted: 01/18/2024] [Indexed: 02/05/2024]
Abstract
Porcine infectious pleuropneumonia (PCP) is a severe disease of porcine caused by Actinobacillus pleuropneumoniae (APP). The spread of PCP remains a threat to the porcine farms and has been known to cause severe economic losses. The cAMP receptor protein (CRP) serves as a pivotal player in helping bacteria adapt to shifts in their environment, particularly when facing the challenges posed by bacterial infections. In this study, we investigated the role of CRP in APP. Our results revealed that crp mutant (Δcrp) strains were more sensitive to acidic and osmotic stress resistance and had lower biofilm formation ability than wild-type (WT) strains. Furthermore, the Δcrp strains showed deficiencies in anti-phagocytosis, adhesion, and invasion upon interaction with host cells. Mice infected with the Δcrp strains demonstrated reduced bacterial loads in their lungs compared to those infected with the WT strains. This study reveals the pivotal role of crp gene expression in regulating pleuropneumonia growth, stress resistance, iron utilization, biofilm formation, phagocytosis, adhesion, invasion and colonization. Our discoveries offer novel perspectives on understanding the development and progression of APP infections.
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Affiliation(s)
- Qiyun He
- National Key Laboratory of Agricultural Microbiology, Hubei Hongshan Laboratory, College of Veterinary Medicine,Huazhong Agricultural University, Wuhan, China; The Cooperative Innovation Center for Sustainable Pig Production, Huazhong Agricultural University, Wuhan, China
| | - Yaxuan Zheng
- National Key Laboratory of Agricultural Microbiology, Hubei Hongshan Laboratory, College of Veterinary Medicine,Huazhong Agricultural University, Wuhan, China; The Cooperative Innovation Center for Sustainable Pig Production, Huazhong Agricultural University, Wuhan, China
| | - Kang Yan
- National Key Laboratory of Agricultural Microbiology, Hubei Hongshan Laboratory, College of Veterinary Medicine,Huazhong Agricultural University, Wuhan, China; The Cooperative Innovation Center for Sustainable Pig Production, Huazhong Agricultural University, Wuhan, China
| | - Jia Tang
- National Key Laboratory of Agricultural Microbiology, Hubei Hongshan Laboratory, College of Veterinary Medicine,Huazhong Agricultural University, Wuhan, China; The Cooperative Innovation Center for Sustainable Pig Production, Huazhong Agricultural University, Wuhan, China
| | - Fengming Yang
- National Key Laboratory of Agricultural Microbiology, Hubei Hongshan Laboratory, College of Veterinary Medicine,Huazhong Agricultural University, Wuhan, China; The Cooperative Innovation Center for Sustainable Pig Production, Huazhong Agricultural University, Wuhan, China
| | - Yanhong Tian
- National Key Laboratory of Agricultural Microbiology, Hubei Hongshan Laboratory, College of Veterinary Medicine,Huazhong Agricultural University, Wuhan, China; The Cooperative Innovation Center for Sustainable Pig Production, Huazhong Agricultural University, Wuhan, China
| | - Lijun Yang
- National Key Laboratory of Agricultural Microbiology, Hubei Hongshan Laboratory, College of Veterinary Medicine,Huazhong Agricultural University, Wuhan, China; The Cooperative Innovation Center for Sustainable Pig Production, Huazhong Agricultural University, Wuhan, China
| | - Beibei Dou
- National Key Laboratory of Agricultural Microbiology, Hubei Hongshan Laboratory, College of Veterinary Medicine,Huazhong Agricultural University, Wuhan, China; The Cooperative Innovation Center for Sustainable Pig Production, Huazhong Agricultural University, Wuhan, China
| | - Yunpeng Chen
- National Key Laboratory of Agricultural Microbiology, Hubei Hongshan Laboratory, College of Veterinary Medicine,Huazhong Agricultural University, Wuhan, China; The Cooperative Innovation Center for Sustainable Pig Production, Huazhong Agricultural University, Wuhan, China
| | - Jun Gu
- National Key Laboratory of Agricultural Microbiology, Hubei Hongshan Laboratory, College of Veterinary Medicine,Huazhong Agricultural University, Wuhan, China; The Cooperative Innovation Center for Sustainable Pig Production, Huazhong Agricultural University, Wuhan, China
| | - Huanchun Chen
- National Key Laboratory of Agricultural Microbiology, Hubei Hongshan Laboratory, College of Veterinary Medicine,Huazhong Agricultural University, Wuhan, China; The Cooperative Innovation Center for Sustainable Pig Production, Huazhong Agricultural University, Wuhan, China
| | - Fangyan Yuan
- Key Laboratory of Prevention and Control Agents for Animal Bacteriosis (Ministry of Agriculture), Institute of Animal Husbandry and Veterinary Sciences, Hubei Academy of Agricultural Sciences, Wuhan, China
| | - Weicheng Bei
- National Key Laboratory of Agricultural Microbiology, Hubei Hongshan Laboratory, College of Veterinary Medicine,Huazhong Agricultural University, Wuhan, China; The Cooperative Innovation Center for Sustainable Pig Production, Huazhong Agricultural University, Wuhan, China.
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2
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Meng X, Liu X, Bao Y, Luo T, Wang J. Effect of citric acid on cell membrane structure and function of Issatchenkia terricola WJL-G4. J Appl Microbiol 2024; 135:lxae057. [PMID: 38449343 DOI: 10.1093/jambio/lxae057] [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: 10/09/2023] [Revised: 02/17/2024] [Accepted: 03/05/2024] [Indexed: 03/08/2024]
Abstract
AIMS This study aimed to investigate the changes of cell membrane structure and function of Issatchenkia terricola under citric acid by performing physiological analysis. METHODS AND RESULTS The membrane integrity, surface hydrophobicity, structure, fluidity, apoptosis, and fatty acid methyl esters composition of I. terricola WJL-G4 cells were determined by propidium iodide staining, microbial adhesion to hydrocarbon test, transmission electron microscopy analysis, fluorescence anisotropy, flow cytometry, and gas chromatography-mass, respectively. The results showed that with the increasing of citric acid concentrations, the cell vitality, membrane integrity, and fluidity of I. terricola reduced; meanwhile, apoptosis rate, membrane permeable, hydrophobicity, and ergosterol contents augmented significantly. Compared to control, the activities of Na+, K+-ATPase, and Ca2+, Mg2+-ATPase increased by 3.73-fold and 6.70-fold, respectively, when citric acid concentration increased to 20 g l-1. The cells cracked and their cytoplasm effused when the citric acid concentration reached 80 g l-1. CONCLUSIONS I. terricola could successfully adjust its membrane structure and function below 60 g l-1 of citric acid. However, for citric acid concentrations above 80 g l-1, its structure and function were dramatically changed, which might result in reduced functionality.
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Affiliation(s)
- Xiangfeng Meng
- College of Life Science, Northeast Forestry University, No. 26, Hexing St., Harbin 150040, China
| | - Xinyi Liu
- College of Life Science, Northeast Forestry University, No. 26, Hexing St., Harbin 150040, China
| | - Yihong Bao
- College of Life Science, Northeast Forestry University, No. 26, Hexing St., Harbin 150040, China
- Key Laboratory of Forest Food Resources Utilization of Heilongjiang Province, No. 26, Hexing St., Harbin 150040, China
| | - Ting Luo
- State Key Laboratory of Food Science and Technology, Nanchang University, No. 999, Xuefu St., Nanchang 330047, China
| | - Jinling Wang
- College of Life Science, Northeast Forestry University, No. 26, Hexing St., Harbin 150040, China
- Key Laboratory of Forest Food Resources Utilization of Heilongjiang Province, No. 26, Hexing St., Harbin 150040, China
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3
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Gao S, Liao Y, He H, Yang H, Yang X, Xu S, Wang X, Chen K, Ouyang P. Advance of tolerance engineering on microbes for industrial production. Synth Syst Biotechnol 2023; 8:697-707. [PMID: 38025766 PMCID: PMC10656194 DOI: 10.1016/j.synbio.2023.10.004] [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: 08/27/2023] [Revised: 10/19/2023] [Accepted: 10/23/2023] [Indexed: 12/01/2023] Open
Abstract
Industrial microbes have become the core of biological manufacturing, which utilized as the cell factory for production of plenty of chemicals, fuels and medicine. However, the challenge that the extreme stress conditions exist in production is unavoidable for cell factory. Consequently, to enhance robustness of the chassis cell lays the foundation for development of bio-manufacturing. Currently, the researches on cell tolerance covered various aspects, involving reshaping regulatory network, cell membrane modification and other stress response. In fact, the strategies employed to improve cell robustness could be summarized into two directions, irrational engineering and rational engineering. In this review, the metabolic engineering technologies on enhancement of microbe tolerance to industrial conditions are summarized. Meanwhile, the novel thoughts emerged with the development of biological instruments and synthetic biology are discussed.
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Affiliation(s)
- Siyuan Gao
- State Key Laboratory of Materials-Oriented Chemical Engineering, College of Biotechnology and Pharmaceutical Engineering, Nanjing Tech University, Nanjing, 211816, Jiangsu, China
| | - Yang Liao
- State Key Laboratory of Materials-Oriented Chemical Engineering, College of Biotechnology and Pharmaceutical Engineering, Nanjing Tech University, Nanjing, 211816, Jiangsu, China
| | - Hao He
- Petrochemical Research Institute of PetroChina Co. Ltd., Beijing, 102206, China
| | - Huiling Yang
- State Key Laboratory of Materials-Oriented Chemical Engineering, College of Biotechnology and Pharmaceutical Engineering, Nanjing Tech University, Nanjing, 211816, Jiangsu, China
| | - Xuewei Yang
- State Key Laboratory of Materials-Oriented Chemical Engineering, College of Biotechnology and Pharmaceutical Engineering, Nanjing Tech University, Nanjing, 211816, Jiangsu, China
| | - Sheng Xu
- State Key Laboratory of Materials-Oriented Chemical Engineering, College of Biotechnology and Pharmaceutical Engineering, Nanjing Tech University, Nanjing, 211816, Jiangsu, China
| | - Xin Wang
- State Key Laboratory of Materials-Oriented Chemical Engineering, College of Biotechnology and Pharmaceutical Engineering, Nanjing Tech University, Nanjing, 211816, Jiangsu, China
| | - Kequan Chen
- State Key Laboratory of Materials-Oriented Chemical Engineering, College of Biotechnology and Pharmaceutical Engineering, Nanjing Tech University, Nanjing, 211816, Jiangsu, China
| | - Pingkai Ouyang
- State Key Laboratory of Materials-Oriented Chemical Engineering, College of Biotechnology and Pharmaceutical Engineering, Nanjing Tech University, Nanjing, 211816, Jiangsu, China
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Re A, Mazzoli R. Current progress on engineering microbial strains and consortia for production of cellulosic butanol through consolidated bioprocessing. Microb Biotechnol 2022; 16:238-261. [PMID: 36168663 PMCID: PMC9871528 DOI: 10.1111/1751-7915.14148] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/11/2022] [Revised: 08/01/2022] [Accepted: 09/07/2022] [Indexed: 01/27/2023] Open
Abstract
In the last decades, fermentative production of n-butanol has regained substantial interest mainly owing to its use as drop-in-fuel. The use of lignocellulose as an alternative to traditional acetone-butanol-ethanol fermentation feedstocks (starchy biomass and molasses) can significantly increase the economic competitiveness of biobutanol over production from non-renewable sources (petroleum). However, the low cost of lignocellulose is offset by its high recalcitrance to biodegradation which generally requires chemical-physical pre-treatment and multiple bioreactor-based processes. The development of consolidated processing (i.e., single-pot fermentation) can dramatically reduce lignocellulose fermentation costs and promote its industrial application. Here, strategies for developing microbial strains and consortia that feature both efficient (hemi)cellulose depolymerization and butanol production will be depicted, that is, rational metabolic engineering of native (hemi)cellulolytic or native butanol-producing or other suitable microorganisms; protoplast fusion of (hemi)cellulolytic and butanol-producing strains; and co-culture of (hemi)cellulolytic and butanol-producing microbes. Irrespective of the fermentation feedstock, biobutanol production is inherently limited by the severe toxicity of this solvent that challenges process economic viability. Hence, an overview of strategies for developing butanol hypertolerant strains will be provided.
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Affiliation(s)
- Angela Re
- Centre for Sustainable Future TechnologiesFondazione Istituto Italiano di TecnologiaTorinoItaly,Department of Applied Science and TechnologyPolitecnico di TorinoTurinItaly
| | - Roberto Mazzoli
- Structural and Functional Biochemistry, Laboratory of Proteomics and Metabolic Engineering of Prokaryotes, Department of Life Sciences and Systems BiologyUniversity of TorinoTorinoItaly
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5
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Liu Y, Yuan H, Ding D, Dong H, Wang Q, Zhang D. Establishment of a Biosensor-based High-Throughput Screening Platform for Tryptophan Overproduction. ACS Synth Biol 2021; 10:1373-1383. [PMID: 34081459 DOI: 10.1021/acssynbio.0c00647] [Citation(s) in RCA: 8] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022]
Abstract
With the flexibility to fold into complex structures, RNA is well-suited to act as a cellular sensor to recognize environmental fluctuations and respond to changes by regulating the corresponding genes. In this study, we established a high-throughput screening platform to screen tryptophan high-producing strains from a large repertoire of candidate strains. This platform consists of a tryptophan-specific aptamer-based biosensor and fluorescence-activated droplet sorting technology. One mutant strain, with a 165.9% increase in Trp titer compared with the parental strain, was successfully screened from a random mutagenesis library. Sequencing results revealed that a total of 10 single-nucleotide polymorphisms were discovered in the genome of the mutant strain, among which CRP(T29K) was proven to significantly increase Trp production through improving the strain's tolerance of the harsh environment during the stationary phase of the fermentation process. Our results indicate that this strategy has great potential for improving the production of other amino acids in Escherichia coli.
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Affiliation(s)
- Yongfei Liu
- Tianjin Institute of Industrial Biotechnology, Chinese Academy of Sciences, Tianjin 300308, China
- Key Laboratory of Systems Microbial Biotechnology, Chinese Academy of Sciences, Tianjin 300308, China
- National Engineering Laboratory for Industrial Enzymes, Tianjin 300308, China
| | - Huiling Yuan
- Tianjin Institute of Industrial Biotechnology, Chinese Academy of Sciences, Tianjin 300308, China
- Key Laboratory of Systems Microbial Biotechnology, Chinese Academy of Sciences, Tianjin 300308, China
- National Engineering Laboratory for Industrial Enzymes, Tianjin 300308, China
| | - Dongqin Ding
- Tianjin Institute of Industrial Biotechnology, Chinese Academy of Sciences, Tianjin 300308, China
- Key Laboratory of Systems Microbial Biotechnology, Chinese Academy of Sciences, Tianjin 300308, China
- National Engineering Laboratory for Industrial Enzymes, Tianjin 300308, China
| | - Huina Dong
- Tianjin Institute of Industrial Biotechnology, Chinese Academy of Sciences, Tianjin 300308, China
- Key Laboratory of Systems Microbial Biotechnology, Chinese Academy of Sciences, Tianjin 300308, China
- National Engineering Laboratory for Industrial Enzymes, Tianjin 300308, China
| | - Qinhong Wang
- Tianjin Institute of Industrial Biotechnology, Chinese Academy of Sciences, Tianjin 300308, China
- Key Laboratory of Systems Microbial Biotechnology, Chinese Academy of Sciences, Tianjin 300308, China
- National Engineering Laboratory for Industrial Enzymes, Tianjin 300308, China
| | - Dawei Zhang
- Tianjin Institute of Industrial Biotechnology, Chinese Academy of Sciences, Tianjin 300308, China
- Key Laboratory of Systems Microbial Biotechnology, Chinese Academy of Sciences, Tianjin 300308, China
- National Engineering Laboratory for Industrial Enzymes, Tianjin 300308, China
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6
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Gao Y, Zhou X, Zhang MM, Liu YJ, Guo XP, Lei CR, Li WJ, Lu D. Response characteristics of the membrane integrity and physiological activities of the mutant strain Y217 under exogenous butanol stress. Appl Microbiol Biotechnol 2021; 105:2455-2472. [PMID: 33606076 DOI: 10.1007/s00253-021-11174-5] [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] [Received: 10/15/2020] [Revised: 01/30/2021] [Accepted: 02/10/2021] [Indexed: 01/05/2023]
Abstract
Butanol inhibits bacterial activity by destroying the cell membrane of Clostridium acetobutylicum strains and altering functionality. Butanol toxicity also results in destruction of the phosphoenolpyruvate-carbohydrate phosphotransferase system (PTS), thereby preventing glucose transport and phosphorylation and inhibiting transmembrane transport and assimilation of sugars, amino acids, and other nutrients. In this study, based on the addition of exogenous butanol, the tangible macro indicators of changes in the carbon ion beam irradiation-mutant Y217 morphology were observed using scanning electron microscopy (SEM). The mutant has lower microbial adhesion to hydrocarbon (MATH) value than C. acetobutylicum ATCC 824 strain. FDA fluorescence intensity and conductivity studies demonstrated the intrinsically low membrane permeability of the mutant membrane, with membrane potential remaining relatively stable. Monounsaturated FAs (MUFAs) accounted for 35.17% of the mutant membrane, and the saturated fatty acids (SFA)/unsaturated fatty acids (UFA) ratio in the mutant cell membrane was 1.65. In addition, we conducted DNA-level analysis of the mutant strain Y217. Expectedly, through screening, we found gene mutant sites encoding membrane-related functions in the mutant, including ATP-binding cassette (ABC) transporter-related genes, predicted membrane proteins, and the PTS transport system. It is noteworthy that an unreported predicted membrane protein (CAC 3309) may be related to changes in mutant cell membrane properties. KEY POINTS: • Mutant Y217 exhibited better membrane integrity and permeability. • Mutant Y217 was more resistant to butanol toxicity. • Some membrane-related genes of mutant Y217 were mutated.
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Affiliation(s)
- Yue Gao
- Institute of Modern Physics, Chinese Academy of Sciences, Lanzhou, 730000, China.,University of Chinese Academy of Sciences, Chinese Academy of Science, Beijing, 100049, China
| | - Xiang Zhou
- Institute of Modern Physics, Chinese Academy of Sciences, Lanzhou, 730000, China.,University of Chinese Academy of Sciences, Chinese Academy of Science, Beijing, 100049, China
| | - Miao-Miao Zhang
- Institute of Modern Physics, Chinese Academy of Sciences, Lanzhou, 730000, China.,University of Chinese Academy of Sciences, Chinese Academy of Science, Beijing, 100049, China.,Gansu Key Laboratory of Microbial Resources Exploitation and Application, Lanzhou, 730070, China
| | - Ya-Jun Liu
- University of Chinese Academy of Sciences, Chinese Academy of Science, Beijing, 100049, China.,Qingdao Institute of Bioenergy and Bioprocess Technology, Chinese Academy of Sciences, Qingdao, 266101, China
| | - Xiao-Peng Guo
- School of Life Science and Engineering, Lanzhou University of Technology, Lanzhou, China
| | - Cai-Rong Lei
- Institute of Modern Physics, Chinese Academy of Sciences, Lanzhou, 730000, China.,University of Chinese Academy of Sciences, Chinese Academy of Science, Beijing, 100049, China
| | - Wen-Jian Li
- Institute of Modern Physics, Chinese Academy of Sciences, Lanzhou, 730000, China.,University of Chinese Academy of Sciences, Chinese Academy of Science, Beijing, 100049, China.,Gansu Key Laboratory of Microbial Resources Exploitation and Application, Lanzhou, 730070, China
| | - Dong Lu
- Institute of Modern Physics, Chinese Academy of Sciences, Lanzhou, 730000, China. .,University of Chinese Academy of Sciences, Chinese Academy of Science, Beijing, 100049, China. .,Gansu Key Laboratory of Microbial Resources Exploitation and Application, Lanzhou, 730070, China.
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7
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How to outwit nature: Omics insight into butanol tolerance. Biotechnol Adv 2020; 46:107658. [PMID: 33220435 DOI: 10.1016/j.biotechadv.2020.107658] [Citation(s) in RCA: 8] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/07/2020] [Revised: 11/10/2020] [Accepted: 11/13/2020] [Indexed: 12/16/2022]
Abstract
The energy crisis, depletion of oil reserves, and global climate changes are pressing problems of developed societies. One possibility to counteract that is microbial production of butanol, a promising new fuel and alternative to many petrochemical reagents. However, the high butanol toxicity to all known microbial species is the main obstacle to its industrial implementation. The present state of the art review aims to expound the recent advances in modern omics approaches to resolving this insurmountable to date problem of low butanol tolerance. Genomics, transcriptomics, and proteomics show that butanol tolerance is a complex phenomenon affecting multiple genes and their expression. Efflux pumps, stress and multidrug response, membrane transport, and redox-related genes are indicated as being most important during butanol challenge, in addition to fine-tuning of global regulators of transcription (Spo0A, GntR), which may further improve tolerance. Lipidomics shows that the alterations in membrane composition (saturated lipids and plasmalogen increase) are very much species-specific and butanol-related. Glycomics discloses the pleiotropic effect of CcpA, the role of alternative sugar transport, and the production of exopolysaccharides as alternative routes to overcoming butanol stress. Unfortunately, the strain that simultaneously syntheses and tolerates butanol in concentrations that allow its commercialization has not yet been discovered or produced. Omics insight will allow the purposeful increase of butanol tolerance in natural and engineered producers and the effective heterologous expression of synthetic butanol pathways in strains hereditary butanol-resistant up to 3.2 - 4.9% (w/v). Future breakthrough can be achieved by a detailed study of the membrane proteome, of which 21% are proteins with unknown functions.
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8
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Chen Y, Boggess EE, Ocasio ER, Warner A, Kerns L, Drapal V, Gossling C, Ross W, Gourse RL, Shao Z, Dickerson J, Mansell TJ, Jarboe LR. Reverse engineering of fatty acid-tolerant Escherichia coli identifies design strategies for robust microbial cell factories. Metab Eng 2020; 61:120-130. [PMID: 32474056 DOI: 10.1016/j.ymben.2020.05.001] [Citation(s) in RCA: 18] [Impact Index Per Article: 4.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/26/2019] [Revised: 02/05/2020] [Accepted: 05/02/2020] [Indexed: 10/24/2022]
Abstract
Adaptive laboratory evolution is often used to improve the performance of microbial cell factories. Reverse engineering of evolved strains enables learning and subsequent incorporation of novel design strategies via the design-build-test-learn cycle. Here, we reverse engineer a strain of Escherichia coli previously evolved for increased tolerance of octanoic acid (C8), an attractive biorenewable chemical, resulting in increased C8 production, increased butanol tolerance, and altered membrane properties. Here, evolution was determined to have occurred first through the restoration of WaaG activity, involved in the production of lipopolysaccharides, then an amino acid change in RpoC, a subunit of RNA polymerase, and finally mutation of the BasS-BasR two component system. All three mutations were required in order to reproduce the increased growth rate in the presence of 20 mM C8 and increased cell surface hydrophobicity; the WaaG and RpoC mutations both contributed to increased C8 titers, with the RpoC mutation appearing to be the major driver of this effect. Each of these mutations contributed to changes in the cell membrane. Increased membrane integrity and rigidity and decreased abundance of extracellular polymeric substances can be attributed to the restoration of WaaG. The increase in average lipid tail length can be attributed to the RpoCH419P mutation, which also confers tolerance to other industrially-relevant inhibitors, such as furfural, vanillin and n-butanol. The RpoCH419P mutation may impact binding or function of the stringent response alarmone ppGpp to RpoC site 1. Each of these mutations provides novel strategies for engineering microbial robustness, particularly at the level of the microbial cell membrane.
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Affiliation(s)
- Yingxi Chen
- Department of Chemical and Biological Engineering, Iowa State University, Ames, IA, 50011, USA
| | - Erin E Boggess
- Department of Electrical and Computer Engineering, Iowa State University, Ames, IA, 50011, USA; Bioinformatics & Computational Biology Graduate Program, Iowa State University, Ames, IA, 50011, USA
| | - Efrain Rodriguez Ocasio
- NSF Center for Biorenewable Chemicals (CBiRC) Research Experience for Undergraduates, Ames, IA, 50011, USA; Industrial Biotechnology Program, University of Puerto Rico Mayagüez, 00681, Puerto Rico
| | - Aric Warner
- Interdepartmental Microbiology Graduate Program, Iowa State University, Ames, IA, 50011, USA
| | - Lucas Kerns
- Department of Chemical and Biological Engineering, Iowa State University, Ames, IA, 50011, USA
| | - Victoria Drapal
- NSF Center for Biorenewable Chemicals (CBiRC) Research Experience for Undergraduates, Ames, IA, 50011, USA; Department of Biological Systems Engineering, University of Nebraska-Lincoln, Lincoln, NE, 68508, USA
| | - Chloe Gossling
- Department of Chemical and Biological Engineering, Iowa State University, Ames, IA, 50011, USA
| | - Wilma Ross
- Department of Bacteriology, University of Wisconsin-Madison, Madison, WI, 53706, USA
| | - Richard L Gourse
- Department of Bacteriology, University of Wisconsin-Madison, Madison, WI, 53706, USA
| | - Zengyi Shao
- Department of Chemical and Biological Engineering, Iowa State University, Ames, IA, 50011, USA; Interdepartmental Microbiology Graduate Program, Iowa State University, Ames, IA, 50011, USA
| | - Julie Dickerson
- Department of Electrical and Computer Engineering, Iowa State University, Ames, IA, 50011, USA; Bioinformatics & Computational Biology Graduate Program, Iowa State University, Ames, IA, 50011, USA
| | - Thomas J Mansell
- Department of Chemical and Biological Engineering, Iowa State University, Ames, IA, 50011, USA; Interdepartmental Microbiology Graduate Program, Iowa State University, Ames, IA, 50011, USA.
| | - Laura R Jarboe
- Department of Chemical and Biological Engineering, Iowa State University, Ames, IA, 50011, USA; Interdepartmental Microbiology Graduate Program, Iowa State University, Ames, IA, 50011, USA.
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Jiang C, Cheng Y, Cao H, Zhang B, Li J, Zhu L, Li Z, Zeng W, Li C, He Q. Effect of cAMP Receptor Protein Gene on Growth Characteristics and Stress Resistance of Haemophilus parasuis Serovar 5. Front Cell Infect Microbiol 2020; 10:19. [PMID: 32158699 PMCID: PMC7052058 DOI: 10.3389/fcimb.2020.00019] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/12/2019] [Accepted: 01/14/2020] [Indexed: 01/19/2023] Open
Abstract
Haemophilus parasuis (HPS), a member of the family Pasteurellaceae, is a common bacteria in the upper respiratory tract of pigs but under certain circumstances can cause serious systemic disease (Glasser's disease) characterized by severe infection of the upper respiratory tract, fibrinous polyserositis, polyarthritis, and meningitis. cAMP receptor protein (CRP) is among the most important global regulators, playing a vital role in adapting to environmental changes during the process of bacterial infection. In order to investigate the function of the crp gene in the growth characteristics of H. parasuis serovar 5 (HPS5) and its ability to overcome adverse environmental stresses, a crp mutant strain (Δcrp) was constructed and verified. In this study, we found that the crp gene was involved in growth rate, biofilm formation, stress tolerance, serum resistance, and iron utilization. Compared with the wild type, both the growth rate of the crp mutant and its resistance to osmotic pressure decreased significantly. Similar phenomena were also found in biofilm formation and iron utilization. However, the resistance to heat shock and serum complement of the crp mutant were enhanced. This study aimed to reveal the function in growth characteristics and stress resistance of the crp gene in HPS5. Whether it relates to virulence requires additional in-depth research.
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Affiliation(s)
- Changsheng Jiang
- State Key Laboratory of Agricultural Microbiology, College of Animal Sciences and Veterinary Medicine, Huazhong Agricultural University, Wuhan, China
| | - Yufang Cheng
- State Key Laboratory of Agricultural Microbiology, College of Animal Sciences and Veterinary Medicine, Huazhong Agricultural University, Wuhan, China
| | - Hua Cao
- State Key Laboratory of Agricultural Microbiology, College of Animal Sciences and Veterinary Medicine, Huazhong Agricultural University, Wuhan, China
| | - Bingzhou Zhang
- State Key Laboratory of Agricultural Microbiology, College of Animal Sciences and Veterinary Medicine, Huazhong Agricultural University, Wuhan, China
| | - Jing Li
- State Key Laboratory of Agricultural Microbiology, College of Animal Sciences and Veterinary Medicine, Huazhong Agricultural University, Wuhan, China
| | - Ling Zhu
- State Key Laboratory of Agricultural Microbiology, College of Animal Sciences and Veterinary Medicine, Huazhong Agricultural University, Wuhan, China
| | - Zhonghua Li
- State Key Laboratory of Agricultural Microbiology, College of Animal Sciences and Veterinary Medicine, Huazhong Agricultural University, Wuhan, China
| | - Wei Zeng
- State Key Laboratory of Agricultural Microbiology, College of Animal Sciences and Veterinary Medicine, Huazhong Agricultural University, Wuhan, China
| | - Chang Li
- State Key Laboratory of Agricultural Microbiology, College of Animal Sciences and Veterinary Medicine, Huazhong Agricultural University, Wuhan, China
| | - Qigai He
- State Key Laboratory of Agricultural Microbiology, College of Animal Sciences and Veterinary Medicine, Huazhong Agricultural University, Wuhan, China.,The Cooperative Innovation Center for Sustainable Pig Production, Wuhan, China
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10
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Combination of the CRP mutation and ptsG deletion in Escherichia coli to efficiently synthesize xylitol from corncob hydrolysates. Appl Microbiol Biotechnol 2020; 104:2039-2050. [PMID: 31950219 DOI: 10.1007/s00253-019-10324-0] [Citation(s) in RCA: 17] [Impact Index Per Article: 4.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/21/2019] [Revised: 12/05/2019] [Accepted: 12/15/2019] [Indexed: 12/16/2022]
Abstract
The biotechnology-based production of xylitol has received widespread attention because it can use cheap and renewable lignocellulose as a raw material, thereby decreasing costs and pollution. The simultaneous use of various sugars in lignocellulose hydrolysates is a primary prerequisite for efficient xylitol production. In this study, a ΔptsG and crp* combinatorial strategy was used to generate Escherichia coli W3110 strain IS5-dI, which completely eliminated glucose repression and simultaneously used glucose and xylose. This strain produced 164 g/L xylitol from detoxified corncob hydrolysates during a fed-batch fermentation in a 15-L bioreactor, which was 14.7% higher than the xylitol produced by the starting strain, IS5-d (143 g/L), and the xylitol productivity was 3.04 g/L/h. These results represent the highest xylitol concentration and productivity reported to date for bacteria and hemicellulosic sugars. Additionally, strain IS5-dG, which differs from IS5-dI at CRP amino acid residue 127 (I127G), was tolerant to the toxins in corncob hydrolysates. In a fed-batch fermentation experiment involving a 15-L bioreactor, IS5-dG produced 137 g/L xylitol from non-detoxified corncob hydrolysates, with a productivity of 1.76 g/L/h. On the basis of these results, we believe that IS5-dI and IS5-dG may be useful host strains for the industrial-scale production of xylitol from detoxified or non-detoxified corncob hydrolysates.
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Xu G, Wu A, Xiao L, Han R, Ni Y. Enhancing butanol tolerance of Escherichia coli reveals hydrophobic interaction of multi-tasking chaperone SecB. BIOTECHNOLOGY FOR BIOFUELS 2019; 12:164. [PMID: 31297152 PMCID: PMC6598250 DOI: 10.1186/s13068-019-1507-7] [Citation(s) in RCA: 10] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Figures] [Subscribe] [Scholar Register] [Received: 02/25/2019] [Accepted: 06/19/2019] [Indexed: 06/09/2023]
Abstract
BACKGROUND Escherichia coli has been proved to be one promising platform chassis for the production of various natural products, such as biofuels. Product toxicity is one of the main bottlenecks for achieving maximum production of biofuels. Host strain engineering is an effective approach to alleviate solvent toxicity issue in fermentation. RESULTS Thirty chaperones were overexpressed in E. coli JM109, and SecB recombinant strain was identified with the highest n-butanol tolerance. The tolerance (T) of E. coli overexpressing SecB, calculated by growth difference in the presence and absence of solvents, was determined to be 9.13% at 1.2% (v/v) butanol, which was 3.2-fold of the control strain. Random mutagenesis of SecB was implemented and homologously overexpressed in E. coli, and mutant SecBT10A was identified from 2800 variants rendering E. coli the highest butanol tolerance. Saturation mutagenesis on T10 site revealed that hydrophobic residues were required for high butanol tolerance of E. coli. Compared with wild-type (WT) SecB, the T of SecBT10A strain was further increased from 9.14 to 14.4% at 1.2% butanol, which was 5.3-fold of control strain. Remarkably, E. coli engineered with SecBT10A could tolerate as high as 1.8% butanol (~ 14.58 g/L). The binding affinity of SecBT10A toward model substrate unfolded maltose binding protein (preMBP) was 11.9-fold of that of WT SecB as determined by isothermal titration calorimetry. Residue T10 locates at the entrance of hydrophobic substrate binding groove of SecB, and might play an important role in recognition and binding of cargo proteins. CONCLUSIONS SecB chaperone was identified by chaperone mining to be effective in enhancing butanol tolerance of E. coli. Maximum butanol tolerance of E. coli could reach 1.6% and 1.8% butanol by engineering single gene of SecB or SecBT10A. Hydrophobic interaction is vital for enhanced binding affinity between SecB and cargo proteins, and therefore improved butanol tolerance.
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Affiliation(s)
- Guochao Xu
- The Key Laboratory of Industrial Biotechnology, Ministry of Education, School of Biotechnology, Jiangnan University, Wuxi, 214122 Jiangsu China
| | - Anning Wu
- The Key Laboratory of Industrial Biotechnology, Ministry of Education, School of Biotechnology, Jiangnan University, Wuxi, 214122 Jiangsu China
| | - Lin Xiao
- The Key Laboratory of Industrial Biotechnology, Ministry of Education, School of Biotechnology, Jiangnan University, Wuxi, 214122 Jiangsu China
| | - Ruizhi Han
- 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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Wang M, Liu GN, Liu H, Zhang L, Li BZ, Li X, Liu D, Yuan YJ. Engineering global transcription to tune lipophilic properties in Yarrowia lipolytica. BIOTECHNOLOGY FOR BIOFUELS 2018; 11:115. [PMID: 29713375 PMCID: PMC5907459 DOI: 10.1186/s13068-018-1114-z] [Citation(s) in RCA: 11] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 11/17/2017] [Accepted: 04/10/2018] [Indexed: 05/26/2023]
Abstract
BACKGROUND Evolution of complex phenotypes in cells requires simultaneously tuning expression of large amounts of genes, which can be achieved by reprograming global transcription. Lipophilicity is an important complex trait in oleaginous yeast Yarrowia lipolytica. It is necessary to explore the changes of which genes' expression levels will tune cellular lipophilic properties via the strategy of global transcription engineering. RESULTS We achieved a strategy of global transcription engineering in Y. lipolytica by modifying the sequences of a key transcriptional factor (TF), SPT15-like (Yl-SPT15). The combinatorial mutagenesis of this gene was achieved by DNA assembly of up to five expression cassettes of its error-prone PCR libraries. A heterologous beta-carotene biosynthetic pathway was constructed to research the effects of combined Yl-SPT15 mutants on carotene and lipid production. As a result, we obtained both an "enhanced" strain with 4.7-fold carotene production and a "weakened" strain with 0.13-fold carotene production relative to the initial strain, nearly 40-fold changing range. Genotype verification, comparative transcriptome analysis, and detection of the amounts of total and free fatty acids were made for the selected strains, indicating effective tuning of cells' lipophilic properties. We exploited the key pathways including RNA polymerase, ketone body metabolism, fatty acid synthesis, and degradation that drastically determined cells' variable lipophilicity. CONCLUSIONS We have examined the effects of combinatorial mutagenesis of Yl-SPT15 on cells' capacity of producing beta-carotene and lipids. The lipophilic properties in Y. lipolytica could be effectively tuned by simultaneously regulating genome-wide multi-gene expression levels. The exploited gene targets and pathways could guide design and reconstruction of yeast cells for tunable and optimal production of other lipophilic products.
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Affiliation(s)
- Man Wang
- Key Laboratory of Systems Bioengineering (Ministry of Education), School of Chemical Engineering and Technology, Tianjin University, Tianjin, 300072 People’s Republic of China
- SynBio Research Platform, Collaborative Innovation Center of Chemical Science and Engineering (Tianjin), Tianjin University, Tianjin, 300072 People’s Republic of China
| | - Guan-Nan Liu
- College of Biotechnology and Pharmaceutical Engineering, Nanjing Tech University, Nanjing, 211816 People’s Republic of China
| | - Hong Liu
- Key Laboratory of Systems Bioengineering (Ministry of Education), School of Chemical Engineering and Technology, Tianjin University, Tianjin, 300072 People’s Republic of China
- SynBio Research Platform, Collaborative Innovation Center of Chemical Science and Engineering (Tianjin), Tianjin University, Tianjin, 300072 People’s Republic of China
| | - Lu Zhang
- Key Laboratory of Systems Bioengineering (Ministry of Education), School of Chemical Engineering and Technology, Tianjin University, Tianjin, 300072 People’s Republic of China
- SynBio Research Platform, Collaborative Innovation Center of Chemical Science and Engineering (Tianjin), Tianjin University, Tianjin, 300072 People’s Republic of China
| | - Bing-Zhi Li
- Key Laboratory of Systems Bioengineering (Ministry of Education), School of Chemical Engineering and Technology, Tianjin University, Tianjin, 300072 People’s Republic of China
- SynBio Research Platform, Collaborative Innovation Center of Chemical Science and Engineering (Tianjin), Tianjin University, Tianjin, 300072 People’s Republic of China
| | - Xia Li
- Key Laboratory of Systems Bioengineering (Ministry of Education), School of Chemical Engineering and Technology, Tianjin University, Tianjin, 300072 People’s Republic of China
- SynBio Research Platform, Collaborative Innovation Center of Chemical Science and Engineering (Tianjin), Tianjin University, Tianjin, 300072 People’s Republic of China
| | - Duo Liu
- Key Laboratory of Systems Bioengineering (Ministry of Education), School of Chemical Engineering and Technology, Tianjin University, Tianjin, 300072 People’s Republic of China
- SynBio Research Platform, Collaborative Innovation Center of Chemical Science and Engineering (Tianjin), Tianjin University, Tianjin, 300072 People’s Republic of China
| | - Ying-Jin Yuan
- Key Laboratory of Systems Bioengineering (Ministry of Education), School of Chemical Engineering and Technology, Tianjin University, Tianjin, 300072 People’s Republic of China
- SynBio Research Platform, Collaborative Innovation Center of Chemical Science and Engineering (Tianjin), Tianjin University, Tianjin, 300072 People’s Republic of China
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Construction of Halomonas bluephagenesis capable of high cell density growth for efficient PHA production. Appl Microbiol Biotechnol 2018; 102:4499-4510. [DOI: 10.1007/s00253-018-8931-7] [Citation(s) in RCA: 23] [Impact Index Per Article: 3.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/12/2018] [Revised: 03/07/2018] [Accepted: 03/10/2018] [Indexed: 12/13/2022]
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14
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Tailoring cyanobacterial cell factory for improved industrial properties. Biotechnol Adv 2018; 36:430-442. [DOI: 10.1016/j.biotechadv.2018.01.005] [Citation(s) in RCA: 52] [Impact Index Per Article: 8.7] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/16/2017] [Revised: 01/07/2018] [Accepted: 01/08/2018] [Indexed: 11/20/2022]
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Basak S, Sahoo NG, Pavanasam AK. Genome mining, in silico validation and phase selection of a novel aldo-keto reductase from Candida glabrata for biotransformation. Bioengineered 2017. [PMID: 28644714 PMCID: PMC5972913 DOI: 10.1080/21655979.2017.1342911] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Abstract] [Key Words] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/24/2022] Open
Abstract
Previously, we published cloning, overexpression, characterization and subsequent exploitation of a carbonyl reductase (cr) gene, belonging to general family aldo-keto reductase from Candida glabrata CBS138 to convert keto ester (COBE) to a chiral alcohol (ethyl-4-chloro-3-hydroxybutanoate or CHBE). Exploiting global transcription factor CRP, rDNA and transporter engineering, we have improved batch production of CHBE by trinomial bioengineering. Herein, we present the exploration of cr gene in Candida glabrata CBS138 through genome mining approach, in silico validation of its activity and selection of its biocatalytic phase. For exploration of the gene under investigation, 3 template genes were chosen namely Saccharomyces cerevisae YDR541c, YGL157w and YOL151w. The CR showed significant homology match, overlapping of substrate binding site and NADPH binding site with the template proteins. The binding affinity of COBE toward CR (-4.6 Kcal/ mol) was found higher than that of the template proteins (-3.5 to -4.5 Kcal/ mol). Biphasic biocatalysis with cofactor regeneration improved product titer 4∼5 times better than monophasic biotransformation. Currently we are working on DNA Shuffling as a next level of strain engineering and we demonstrate this approach herein as a future strategy of biochemical engineering.
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Affiliation(s)
- Souvik Basak
- a Dr. B.C. Roy College of Pharmacy & Allied Health Sciences , Durgapur , WB , India
| | - Nanda Gopal Sahoo
- b Nanoscience and Nanotechnology Centre, Department of Chemistry , Kumaun University , Nainital , Uttarakhand , India
| | - Angayar K Pavanasam
- c International College of Engineering and Management (University of Central Lancashire, UK Affiliation) , Muscat , Oman
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Chin WC, Lin KH, Liu CC, Tsuge K, Huang CC. Improved n-butanol production via co-expression of membrane-targeted tilapia metallothionein and the clostridial metabolic pathway in Escherichia coli. BMC Biotechnol 2017; 17:36. [PMID: 28399854 PMCID: PMC5387206 DOI: 10.1186/s12896-017-0356-3] [Citation(s) in RCA: 16] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/27/2016] [Accepted: 03/22/2017] [Indexed: 11/10/2022] Open
Abstract
Background N-Butanol has favorable characteristics for use as either an alternative fuel or platform chemical. Bio-based n-butanol production using microbes is an emerging technology that requires further development. Although bio-industrial microbes such as Escherichia coli have been engineered to produce n-butanol, reactive oxygen species (ROS)-mediated toxicity may limit productivity. Previously, we show that outer-membrane-targeted tilapia metallothionein (OmpC-TMT) is more effective as an ROS scavenger than human and mouse metallothioneins to reduce oxidative stress in the host cell. Results The host strain (BUT1-DE) containing the clostridial n-butanol pathway displayed a decreased growth rate and limited n-butanol productivity, likely due to ROS accumulation. The clostridial n-butanol pathway was co-engineered with inducible OmpC-TMT in E. coli (BUT3-DE) for simultaneous ROS removal, and its effect on n-butanol productivity was examined. The ROS scavenging ability of cells overexpressing OmpC-TMT was examined and showed an approximately twofold increase in capacity. The modified strain improved n-butanol productivity to 320 mg/L, whereas the control strain produced only 95.1 mg/L. Transcriptomic analysis revealed three major KEGG pathways that were significantly differentially expressed in the BUT3-DE strain compared with their expression in the BUT1-DE strain, including genes involved in oxidative phosphorylation, fructose and mannose metabolism and glycolysis/gluconeogenesis. Conclusions These results indicate that OmpC-TMT can increase n-butanol production by scavenging ROS. The transcriptomic analysis suggested that n-butanol causes quinone malfunction, resulting in oxidative-phosphorylation-related nuo operon downregulation, which would diminish the ability to convert NADH to NAD+ and generate proton motive force. However, fructose and mannose metabolism-related genes (fucA, srlE and srlA) were upregulated, and glycolysis/gluconeogenesis-related genes (pfkB, pgm) were downregulated, which further assisted in regulating NADH/NAD+ redox and preventing additional ATP depletion. These results indicated that more NADH and ATP were required in the n-butanol synthetic pathway. Our study demonstrates a potential approach to increase the robustness of microorganisms and the production of toxic chemicals through the ability to reduce oxidative stress. Electronic supplementary material The online version of this article (doi:10.1186/s12896-017-0356-3) contains supplementary material, which is available to authorized users.
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Affiliation(s)
- Wei-Chih Chin
- Department of Life Sciences, National Chung Hsing University, Taichung, Taiwan
| | - Kuo-Hsing Lin
- Center of Cold Chain Logistics Certification, College of Management, National Kaohsiung First University of Science and Technology, Kaohsiung, Taiwan
| | - Chun-Chi Liu
- Institute of Genomics and Bioinformatics, National Chung Hsing University, Taichung, 402, Taiwan
| | - Kenji Tsuge
- Graduate School of Science, Technology and Innovation, Kobe University, Kobe, Japan
| | - Chieh-Chen Huang
- Department of Life Sciences, National Chung Hsing University, Taichung, Taiwan.
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Li HG, Ma XX, Zhang QH, Luo W, Wu YQ, Li XH. Enhanced butanol production by solvent tolerance Clostridium acetobutylicum SE25 from cassava flour in a fibrous bed bioreactor. BIORESOURCE TECHNOLOGY 2016; 221:412-418. [PMID: 27660992 DOI: 10.1016/j.biortech.2016.08.120] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 07/07/2016] [Revised: 08/25/2016] [Accepted: 08/26/2016] [Indexed: 05/02/2023]
Abstract
To enhance the butanol productivity and reduce the material cost, acetone, butanol, and ethanol fermentation by Clostridium acetobutylicum SE25 was investigated using batch, repeated-batch and continuous cultures in a fibrous bed bioreactor, where cassava flour was used as the substrate. With periodical nutrient supplementation, stable butanol production was maintained for about 360h in a 6-cycle repeated-batch fermentation with an average butanol productivity of 0.28g/L/h and butanol yield of 0.32g/g-starch. In addition, the highest butanol productivity of 0.63g/L/h and butanol yield of 0.36g/g-starch were achieved when the dilution rate were investigated in continuous production of acetone, butanol, and ethanol using a fibrous bed bioreactor, which were 231.6% and 28.6% higher than those of the free-cell fermentation. On the other hand, this study also successfully comfirmed that the biofilm can provide an effective protection for the microbial cells which are growing in stressful environment.
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Affiliation(s)
- Han-Guang Li
- College of Bioscience and Engineering, Jiangxi Agricultural University, Jiangxi Engineering Laboratory for the Development and Utilization of Agricultural Microbial Resources, Nanchang 330045, China
| | - Xing-Xing Ma
- College of Bioscience and Engineering, Jiangxi Agricultural University, Jiangxi Engineering Laboratory for the Development and Utilization of Agricultural Microbial Resources, Nanchang 330045, China
| | - Qing-Hua Zhang
- College of Bioscience and Engineering, Jiangxi Agricultural University, Jiangxi Engineering Laboratory for the Development and Utilization of Agricultural Microbial Resources, Nanchang 330045, China.
| | - Wei Luo
- The Key Laboratory of Industrial Biotechnology, Ministry of Education, School of Biotechnology, Jiangnan University, Wuxi 214122, China
| | - Ya-Qing Wu
- College of Bioscience and Engineering, Jiangxi Agricultural University, Jiangxi Engineering Laboratory for the Development and Utilization of Agricultural Microbial Resources, Nanchang 330045, China
| | - Xun-Hang Li
- College of Bioscience and Engineering, Jiangxi Agricultural University, Jiangxi Engineering Laboratory for the Development and Utilization of Agricultural Microbial Resources, Nanchang 330045, China
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Rau MH, Calero P, Lennen RM, Long KS, Nielsen AT. Genome-wide Escherichia coli stress response and improved tolerance towards industrially relevant chemicals. Microb Cell Fact 2016; 15:176. [PMID: 27737709 PMCID: PMC5064937 DOI: 10.1186/s12934-016-0577-5] [Citation(s) in RCA: 37] [Impact Index Per Article: 4.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/17/2016] [Accepted: 10/03/2016] [Indexed: 01/17/2023] Open
Abstract
Background Economically viable biobased production of bulk chemicals and biofuels typically requires high product titers. During microbial bioconversion this often leads to product toxicity, and tolerance is therefore a critical element in the engineering of production strains. Results Here, a systems biology approach was employed to understand the chemical stress response of Escherichia coli, including a genome-wide screen for mutants with increased fitness during chemical stress. Twelve chemicals with significant production potential were selected, consisting of organic solvent-like chemicals (butanol, hydroxy-γ-butyrolactone, 1,4-butanediol, furfural), organic acids (acetate, itaconic acid, levulinic acid, succinic acid), amino acids (serine, threonine) and membrane-intercalating chemicals (decanoic acid, geraniol). The transcriptional response towards these chemicals revealed large overlaps of transcription changes within and between chemical groups, with functions such as energy metabolism, stress response, membrane modification, transporters and iron metabolism being affected. Regulon enrichment analysis identified key regulators likely mediating the transcriptional response, including CRP, RpoS, OmpR, ArcA, Fur and GadX. These regulators, the genes within their regulons and the above mentioned cellular functions therefore constitute potential targets for increasing E. coli chemical tolerance. Fitness determination of genome-wide transposon mutants (Tn-seq) subjected to the same chemical stress identified 294 enriched and 336 depleted mutants and experimental validation revealed up to 60 % increase in mutant growth rates. Mutants enriched in several conditions contained, among others, insertions in genes of the Mar-Sox-Rob regulon as well as transcription and translation related gene functions. Conclusions The combination of the transcriptional response and mutant screening provides general targets that can increase tolerance towards not only single, but multiple chemicals. Electronic supplementary material The online version of this article (doi:10.1186/s12934-016-0577-5) contains supplementary material, which is available to authorized users.
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Affiliation(s)
- Martin Holm Rau
- Novo Nordisk Foundation Center for Biosustainability, Technical University of Denmark, Hørsholm, Denmark
| | - Patricia Calero
- Novo Nordisk Foundation Center for Biosustainability, Technical University of Denmark, Hørsholm, Denmark
| | - Rebecca M Lennen
- Novo Nordisk Foundation Center for Biosustainability, Technical University of Denmark, Hørsholm, Denmark
| | - Katherine S Long
- Novo Nordisk Foundation Center for Biosustainability, Technical University of Denmark, Hørsholm, Denmark
| | - Alex T Nielsen
- Novo Nordisk Foundation Center for Biosustainability, Technical University of Denmark, Hørsholm, Denmark.
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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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Tan F, Wu B, Dai L, Qin H, Shui Z, Wang J, Zhu Q, Hu G, He M. Using global transcription machinery engineering (gTME) to improve ethanol tolerance of Zymomonas mobilis. Microb Cell Fact 2016; 15:4. [PMID: 26758018 PMCID: PMC4711062 DOI: 10.1186/s12934-015-0398-y] [Citation(s) in RCA: 51] [Impact Index Per Article: 6.4] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/28/2015] [Accepted: 12/15/2015] [Indexed: 12/17/2022] Open
Abstract
BACKGROUND With the increasing global crude oil crisis and resulting environmental concerns, the production of biofuels from renewable resources has become increasingly important. One of the major challenges faced during the process of biofuel production is the low tolerance of the microbial host towards increasing biofuel concentrations. RESULTS Here, we demonstrate that the ethanol tolerance of Zymomonas mobilis can be greatly enhanced through the random mutagenesis of global transcription factor RpoD protein, (σ(70)). Using an enrichment screening, four mutants with elevated ethanol tolerance were isolated from error-prone PCR libraries. All mutants showed significant growth improvement in the presence of ethanol stress when compared to the control strain. After an ethanol (9 %) stress exposure lasting 22 h, the rate of glucose consumption was approximately 1.77, 1.78 and 1.39 g L(-1) h(-1) in the best ethanol-tolerant strain ZM4-mrpoD4, its rebuilt mutant strain ZM4-imrpoD and the control strain, respectively. Our results indicated that both ZM4-mrpoD4 and ZM4-imrpoD consumed glucose at a faster rate after the initial 9 % (v/v) ethanol stress, as nearly 0.64 % of the initial glucose remained after 54 h incubation versus approximately 5.43 % for the control strain. At 9 % ethanol stress, the net ethanol productions by ZM4-mrpoD4 and ZM4-imrpoD during the 30-54 h were 13.0-14.1 g/l versus only 6.6-7.7 g/l for the control strain. The pyruvate decarboxylase activity of ZM4-mrpoD4 was 62.23 and 68.42 U/g at 24 and 48 h, respectively, which were 2.6 and 1.6 times higher than the control strain. After 24 and 48 h of 9 % ethanol stress, the alcohol dehydrogenase activities of ZM4-mrpoD4 were also augmented, showing an approximate 1.4 and 1.3 times increase, respectively, when compared to the control strain. Subsequent quantitative real-time PCR analysis under these stress conditions revealed that the relative expression of pdc in cultured (6 and 24 h) ZM4-mrpoD4 increased by 9.0- and 12.7-fold when compared to control strain. CONCLUSIONS Collectively, these results demonstrate that the RpoD mutation can enhance ethanol tolerance in Z. mobilis. Our results also suggested that RpoD may play an important role in resisting high ethanol concentration in Z. mobilis and manipulating RpoD via global transcription machinery engineering (gTME) can provide an alternative and useful approach for strain improvement for complex phenotypes.
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Affiliation(s)
- Furong Tan
- Biogas Institute of Ministry of Agriculture, Biomass Energy Technology Research Centre, Section 4-13, Renmin Nanlu, Chengdu, 610041, China.
| | - Bo Wu
- Biogas Institute of Ministry of Agriculture, Biomass Energy Technology Research Centre, Section 4-13, Renmin Nanlu, Chengdu, 610041, China.
| | - Lichun Dai
- Biogas Institute of Ministry of Agriculture, Biomass Energy Technology Research Centre, Section 4-13, Renmin Nanlu, Chengdu, 610041, China.
| | - Han Qin
- Biogas Institute of Ministry of Agriculture, Biomass Energy Technology Research Centre, Section 4-13, Renmin Nanlu, Chengdu, 610041, China.
| | - Zongxia Shui
- Biogas Institute of Ministry of Agriculture, Biomass Energy Technology Research Centre, Section 4-13, Renmin Nanlu, Chengdu, 610041, China.
| | - Jingli Wang
- Biogas Institute of Ministry of Agriculture, Biomass Energy Technology Research Centre, Section 4-13, Renmin Nanlu, Chengdu, 610041, China.
| | - Qili Zhu
- Biogas Institute of Ministry of Agriculture, Biomass Energy Technology Research Centre, Section 4-13, Renmin Nanlu, Chengdu, 610041, China.
| | - Guoquan Hu
- Biogas Institute of Ministry of Agriculture, Biomass Energy Technology Research Centre, Section 4-13, Renmin Nanlu, Chengdu, 610041, China.
- Key Laboratory of Development and Application of Rural Renewable Energy, Ministry of Agriculture, Chengdu, 610041, China.
| | - Mingxiong He
- Biogas Institute of Ministry of Agriculture, Biomass Energy Technology Research Centre, Section 4-13, Renmin Nanlu, Chengdu, 610041, China.
- Key Laboratory of Development and Application of Rural Renewable Energy, Ministry of Agriculture, Chengdu, 610041, China.
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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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Zhang F, Qian X, Si H, Xu G, Han R, Ni Y. Significantly improved solvent tolerance of Escherichia coli by global transcription machinery engineering. Microb Cell Fact 2015; 14:175. [PMID: 26542360 PMCID: PMC4635540 DOI: 10.1186/s12934-015-0368-4] [Citation(s) in RCA: 36] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/30/2015] [Accepted: 09/26/2015] [Indexed: 11/10/2022] Open
Abstract
BACKGROUND Escherichia coli has emerged as a promising platform microorganism to produce biofuels and fine chemicals of industrial interests. Certain obstacles however remain to be overcome, among which organic-solvent tolerance is a crucial one. RESULTS We used global transcription machinery engineering (gTME) to improve the organic-solvent tolerance (OST) of E. coli JM109. A mutant library of σ(70) encoded by rpoD was screened under cyclohexane pressure. E. coli JM109 strain harboring σ(70) mutant C9 was identified with capability of tolerating 69 % cyclohexane. The rpoD mutant contains three amino-acid substitutes and a stop-codon mutation, resulting a truncated sequence containing regions σ(1.1) and σ(1.2). Total protein difference produced by E. coli JM109 strain harboring C9 was examined with 2D-PAGE, and 204 high-abundant proteins showed over twofold variation under different solvent stress. CONCLUSIONS Our results show that several genes (gapA, sdhB, pepB and dppA) play critical roles in enhanced solvent tolerance of E. coli, mainly involving in maintaining higher intracellular energy level under solvent stress. Global transcription machinery engineering is therefore a feasible and efficient approach for engineering strain with enhanced OST-phenotype.
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Affiliation(s)
- Fa Zhang
- The Key Laboratory of Industrial Biotechnology, Ministry of Education, School of Biotechnology, Jiangnan University, 214122, Wuxi, Jiangsu, China.
| | - Xiaohong Qian
- The Key Laboratory of Industrial Biotechnology, Ministry of Education, School of Biotechnology, Jiangnan University, 214122, Wuxi, Jiangsu, China.
| | - Haiming Si
- The Key Laboratory of Industrial Biotechnology, Ministry of Education, School of Biotechnology, Jiangnan University, 214122, Wuxi, Jiangsu, China.
| | - Guochao Xu
- The Key Laboratory of Industrial Biotechnology, Ministry of Education, School of Biotechnology, Jiangnan University, 214122, Wuxi, Jiangsu, China.
| | - Ruizhi Han
- The Key Laboratory of Industrial Biotechnology, Ministry of Education, School of Biotechnology, Jiangnan University, 214122, Wuxi, Jiangsu, China.
| | - Ye Ni
- The Key Laboratory of Industrial Biotechnology, Ministry of Education, School of Biotechnology, Jiangnan University, 214122, Wuxi, Jiangsu, China.
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23
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Hinks J, Wang Y, Matysik A, Kraut R, Kjelleberg S, Mu Y, Bazan GC, Wuertz S, Seviour T. Increased Microbial Butanol Tolerance by Exogenous Membrane Insertion Molecules. CHEMSUSCHEM 2015; 8:3718-3726. [PMID: 26404512 DOI: 10.1002/cssc.201500194] [Citation(s) in RCA: 12] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 02/05/2015] [Revised: 07/13/2015] [Indexed: 06/05/2023]
Abstract
Butanol is an ideal biofuel, although poor titers lead to high recovery costs by distillation. Fluidization of microbial membranes by butanol is one of the major factors limiting titers in butanol-producing bioprocesses. Starting with the hypothesis that certain membrane insertion molecules would stabilize the lipid bilayer in the presence of butanol, we applied a combination of in vivo and in vitro techniques within an in silico framework to describe a new approach to achieve solvent tolerance in bacteria. Single-molecule tracking of a model supported bilayer showed that COE1-5C, a five-ringed oligo-polyphenylenevinylene conjugated oligoelectrolyte (COE), reduced the diffusion rate of phospholipids in a microbially derived lipid bilayer to a greater extent than three-ringed and four-ringed COEs. Furthermore, COE1-5C treatment increased the specific growth rate of E. coli K12 relative to a control at inhibitory butanol concentrations. Consequently, to confer butanol tolerance to microbes by exogenous means is complementary to genetic modification of strains in industrial bioprocesses, extends the physiological range of microbes to match favorable bioprocess conditions, and is amenable with complex and undefined microbial consortia for biobutanol production. Molecular dynamics simulations indicated that the π-conjugated aromatic backbone of COE1-5C likely acts as a hydrophobic tether for glycerophospholipid acyl chains by enhancing bilayer integrity in the presence of high butanol concentrations, which thereby counters membrane fluidization. COE1-5C-mitigated E. coli K12 membrane depolarization by butanol is consistent with the hypothesis that improved growth rates in the presence of butanol are a consequence of improved bilayer stability.
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Affiliation(s)
- Jamie Hinks
- Singapore Centre for Environmental Life Sciences Engineering (SCELSE), Nanyang Technological University, Singapore, 637551, Singapore.
| | - Yaofeng Wang
- School of Biological Sciences, Nanyang Technological University, Singapore, 637551, Singapore
| | - Artur Matysik
- Division of Molecular Genetics and Cell Biology, School of Biological Sciences, Nanyang Technological University, Singapore, 637551, Singapore
| | - Rachel Kraut
- Division of Molecular Genetics and Cell Biology, School of Biological Sciences, Nanyang Technological University, Singapore, 637551, Singapore
| | - Staffan Kjelleberg
- Singapore Centre for Environmental Life Sciences Engineering (SCELSE), Nanyang Technological University, Singapore, 637551, Singapore
- School of Biological Sciences, Nanyang Technological University, Singapore, 637551, Singapore
- Centre for Marine BioInnovation and School of Biotechnology and Bimolecular Sciences, University of New South Wales, Sydney, 2052, Australia
| | - Yuguang Mu
- School of Biological Sciences, Nanyang Technological University, Singapore, 637551, Singapore
| | - Guillermo C Bazan
- Department of Chemistry & Biochemistry and Materials, Center for Polymers and Organic Solids, University of California, Santa Barbara, California, 93106, USA
| | - Stefan Wuertz
- Singapore Centre for Environmental Life Sciences Engineering (SCELSE), Nanyang Technological University, Singapore, 637551, Singapore
- Department of Civil and Environmental Engineering, University of California, Davis, California, 95616, USA
| | - Thomas Seviour
- Singapore Centre for Environmental Life Sciences Engineering (SCELSE), Nanyang Technological University, Singapore, 637551, Singapore.
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24
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cAMP receptor protein (CRP)-mediated resistance/tolerance in bacteria: mechanism and utilization in biotechnology. Appl Microbiol Biotechnol 2015; 99:4533-43. [DOI: 10.1007/s00253-015-6587-0] [Citation(s) in RCA: 16] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/13/2015] [Revised: 03/31/2015] [Accepted: 04/03/2015] [Indexed: 02/05/2023]
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25
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Huang L, Pu Y, Yang X, Zhu X, Cai J, Xu Z. Engineering of global regulator cAMP receptor protein (CRP) in Escherichia coli for improved lycopene production. J Biotechnol 2015; 199:55-61. [PMID: 25687103 DOI: 10.1016/j.jbiotec.2015.02.006] [Citation(s) in RCA: 20] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/23/2014] [Revised: 02/05/2015] [Accepted: 02/05/2015] [Indexed: 01/23/2023]
Abstract
Transcriptional engineering has received significant attention for improving strains by modulating the behavior of transcription factors, which could be used to reprogram a series of gene transcriptions and enable multiple simultaneous modifications at the genomic level. In this study, engineering of the cAMP receptor protein (CRP) was explored with the aim of subtly balancing entire pathway networks and potentially improving lycopene production without significant genetic intervention in other pathways. Amino acid mutations were introduced to CRP by error-prone PCR, and three variants (mcrp26, mcrp159 and mcrp424) with increased lycopene productivity were screened. Combinations of three point mutations were then created via site-directed mutagenesis. The best mutant gene (mcrp26) was integrated into the genome of E. coli BW25113-BIE to replace the wild-type crp gene (MT-1), which resulted in a higher lycopene production (18.49mg/g DCW) compared to the original strain (WT). The mutant strain MT-1 was further investigated in a 10-L bench-top fermentor with a lycopene yield of 128mg/l at 20h, approximately 25% higher than WT. DNA microarray analyses showed that 396 genes (229 up-regulated and 167 down-regulated) were differentially expressed in the mutant MT-1 compared to WT. Finally, the introduction of the mutant crp gene (mcrp26) increased β-carotene production in E. coli. This is the first report of improving the phenotype for metabolite overproduction in E. coli using a CRP engineering strategy.
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Affiliation(s)
- Lei Huang
- Institute of Bioengineering, College of Chemical and Biological Engineering, Zhejiang University, Hangzhou, China
| | - Yue Pu
- Institute of Bioengineering, College of Chemical and Biological Engineering, Zhejiang University, Hangzhou, China
| | - Xiuliang Yang
- Shangdong Jincheng Biopharmaceutical Corporation Limited, Zibo, China
| | - Xiangcheng Zhu
- Hunan Engineering Research Center of Combinatorial Biosynthesis and Natural Product Drug Discovery, Changsha, China
| | - Jin Cai
- Institute of Bioengineering, College of Chemical and Biological Engineering, Zhejiang University, Hangzhou, China
| | - Zhinan Xu
- Institute of Bioengineering, College of Chemical and Biological Engineering, Zhejiang University, Hangzhou, China.
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26
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Liu W, Jiang R. Combinatorial and high-throughput screening approaches for strain engineering. Appl Microbiol Biotechnol 2015; 99:2093-104. [DOI: 10.1007/s00253-015-6400-0] [Citation(s) in RCA: 17] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/18/2014] [Revised: 01/09/2015] [Accepted: 01/10/2015] [Indexed: 12/31/2022]
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27
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Shimizu K. Metabolic Regulation and Coordination of the Metabolism in Bacteria in Response to a Variety of Growth Conditions. ADVANCES IN BIOCHEMICAL ENGINEERING/BIOTECHNOLOGY 2015; 155:1-54. [PMID: 25712586 DOI: 10.1007/10_2015_320] [Citation(s) in RCA: 25] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 12/22/2022]
Abstract
Living organisms have sophisticated but well-organized regulation system. It is important to understand the metabolic regulation mechanisms in relation to growth environment for the efficient design of cell factories for biofuels and biochemicals production. Here, an overview is given for carbon catabolite regulation, nitrogen regulation, ion, sulfur, and phosphate regulations, stringent response under nutrient starvation as well as oxidative stress regulation, redox state regulation, acid-shock, heat- and cold-shock regulations, solvent stress regulation, osmoregulation, and biofilm formation, and quorum sensing focusing on Escherichia coli metabolism and others. The coordinated regulation mechanisms are of particular interest in getting insight into the principle which governs the cell metabolism. The metabolism is controlled by both enzyme-level regulation and transcriptional regulation via transcription factors such as cAMP-Crp, Cra, Csr, Fis, P(II)(GlnB), NtrBC, CysB, PhoR/B, SoxR/S, Fur, MarR, ArcA/B, Fnr, NarX/L, RpoS, and (p)ppGpp for stringent response, where the timescales for enzyme-level and gene-level regulations are different. Moreover, multiple regulations are coordinated by the intracellular metabolites, where fructose 1,6-bisphosphate (FBP), phosphoenolpyruvate (PEP), and acetyl-CoA (AcCoA) play important roles for enzyme-level regulation as well as transcriptional control, while α-ketoacids such as α-ketoglutaric acid (αKG), pyruvate (PYR), and oxaloacetate (OAA) play important roles for the coordinated regulation between carbon source uptake rate and other nutrient uptake rate such as nitrogen or sulfur uptake rate by modulation of cAMP via Cya.
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Affiliation(s)
- Kazuyuki Shimizu
- Kyushu Institute of Technology, Iizuka, Fukuoka, 820-8502, Japan. .,Institute of Advanced Biosciences, Keio University, Tsuruoka, Yamagata, 997-0017, Japan.
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28
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Dong H, Zhao C, Zhang T, Lin Z, Li Y, Zhang Y. Engineering Escherichia coli Cell Factories for n-Butanol Production. ADVANCES IN BIOCHEMICAL ENGINEERING/BIOTECHNOLOGY 2015; 155:141-63. [PMID: 25662903 DOI: 10.1007/10_2015_306] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 01/25/2023]
Abstract
The production of n-butanol, as a widely applied solvent and potential fuel, is attracting much attention. The fermentative production of butanol coupled with the production of acetone and ethanol by Clostridium (ABE fermentation) was once one of the oldest biotechnological processes, ranking second in scale behind ethanol fermentation. However, there remain problems with butanol production by Clostridium, especially the difficulty in genetically manipulating clostridial strains. In recent years, many efforts have been made to produce butanol using non-native strains. Until now, the most advanced effort was the engineering of the user-friendly and widely studied Escherichia coli for butanol production. This paper reviews the current progress and problems relating to butanol production by engineered E. coli in terms of prediction using mathematical models, pathway construction, novel enzyme replacement, butanol toxicity, and tolerance engineering strategies.
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Affiliation(s)
- Hongjun Dong
- CAS Key Laboratory of Microbial Physiological and Metabolic Engineering, Institute of Microbiology, Chinese Academy of Sciences, Beijing, 100101, China
| | - Chunhua Zhao
- CAS Key Laboratory of Microbial Physiological and Metabolic Engineering, Institute of Microbiology, Chinese Academy of Sciences, Beijing, 100101, China
- University of Chinese Academy of Sciences, Beijing, 100049, China
| | - Tianrui Zhang
- CAS Key Laboratory of Microbial Physiological and Metabolic Engineering, Institute of Microbiology, Chinese Academy of Sciences, Beijing, 100101, China
- Tianjin Institute of Industrial Biotechnology, Chinese Academy of Sciences, Tianjin, 300308, China
| | - Zhao Lin
- University of Chinese Academy of Sciences, Beijing, 100049, China
| | - Yin Li
- CAS Key Laboratory of Microbial Physiological and Metabolic Engineering, Institute of Microbiology, Chinese Academy of Sciences, Beijing, 100101, China
| | - Yanping Zhang
- CAS Key Laboratory of Microbial Physiological and Metabolic Engineering, Institute of Microbiology, Chinese Academy of Sciences, Beijing, 100101, China.
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29
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Yu AQ, Pratomo Juwono NK, Leong SSJ, Chang MW. Production of Fatty Acid-derived valuable chemicals in synthetic microbes. Front Bioeng Biotechnol 2014; 2:78. [PMID: 25566540 PMCID: PMC4275033 DOI: 10.3389/fbioe.2014.00078] [Citation(s) in RCA: 36] [Impact Index Per Article: 3.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/29/2014] [Accepted: 12/10/2014] [Indexed: 12/18/2022] Open
Abstract
Fatty acid derivatives, such as hydroxy fatty acids, fatty alcohols, fatty acid methyl/ethyl esters, and fatty alka(e)nes, have a wide range of industrial applications including plastics, lubricants, and fuels. Currently, these chemicals are obtained mainly through chemical synthesis, which is complex and costly, and their availability from natural biological sources is extremely limited. Metabolic engineering of microorganisms has provided a platform for effective production of these valuable biochemicals. Notably, synthetic biology-based metabolic engineering strategies have been extensively applied to refactor microorganisms for improved biochemical production. Here, we reviewed: (i) the current status of metabolic engineering of microbes that produce fatty acid-derived valuable chemicals, and (ii) the recent progress of synthetic biology approaches that assist metabolic engineering, such as mRNA secondary structure engineering, sensor-regulator system, regulatable expression system, ultrasensitive input/output control system, and computer science-based design of complex gene circuits. Furthermore, key challenges and strategies were discussed. Finally, we concluded that synthetic biology provides useful metabolic engineering strategies for economically viable production of fatty acid-derived valuable chemicals in engineered microbes.
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Affiliation(s)
- Ai-Qun Yu
- Department of Biochemistry, Yong Loo Lin School of Medicine, National University of Singapore , Singapore , Singapore ; Synthetic Biology Research Program, National University of Singapore , Singapore , Singapore
| | - Nina Kurniasih Pratomo Juwono
- Department of Biochemistry, Yong Loo Lin School of Medicine, National University of Singapore , Singapore , Singapore ; Synthetic Biology Research Program, National University of Singapore , Singapore , Singapore
| | - Susanna Su Jan Leong
- Department of Biochemistry, Yong Loo Lin School of Medicine, National University of Singapore , Singapore , Singapore ; Synthetic Biology Research Program, National University of Singapore , Singapore , Singapore ; Singapore Institute of Technology , Singapore , Singapore
| | - Matthew Wook Chang
- Department of Biochemistry, Yong Loo Lin School of Medicine, National University of Singapore , Singapore , Singapore ; Synthetic Biology Research Program, National University of Singapore , Singapore , Singapore
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30
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Jia H, Fan Y, Feng X, Li C. Enhancing stress-resistance for efficient microbial biotransformations by synthetic biology. Front Bioeng Biotechnol 2014; 2:44. [PMID: 25368869 PMCID: PMC4202804 DOI: 10.3389/fbioe.2014.00044] [Citation(s) in RCA: 11] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/15/2014] [Accepted: 10/04/2014] [Indexed: 12/23/2022] Open
Abstract
Chemical conversions mediated by microorganisms, otherwise known as microbial biotransformations, are playing an increasingly important role within the biotechnology industry. Unfortunately, the growth and production of microorganisms are often hampered by a number of stressful conditions emanating from environment fluctuations and/or metabolic imbalances such as high temperature, high salt condition, strongly acidic solution, and presence of toxic metabolites. Therefore, exploring methods to improve the stress tolerance of host organisms could significantly improve the biotransformation process. With the help of synthetic biology, it is now becoming feasible to implement strategies to improve the stress-resistance of the existing hosts. This review summarizes synthetic biology efforts to enhance the efficiency of biotransformations by improving the robustness of microbes. Particular attention will be given to strategies at the cellular and the microbial community levels.
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Affiliation(s)
- Haiyang Jia
- Department of Biological Engineering, School of Life Science, Beijing Institute of Technology , Beijing , China
| | - Yanshuang Fan
- Department of Biological Engineering, School of Life Science, Beijing Institute of Technology , Beijing , China
| | - Xudong Feng
- Department of Biological Engineering, School of Life Science, Beijing Institute of Technology , Beijing , China
| | - Chun Li
- Department of Biological Engineering, School of Life Science, Beijing Institute of Technology , Beijing , China
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31
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Microbial tolerance engineering toward biochemical production: from lignocellulose to products. Curr Opin Biotechnol 2014; 29:99-106. [DOI: 10.1016/j.copbio.2014.03.005] [Citation(s) in RCA: 67] [Impact Index Per Article: 6.7] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/14/2013] [Revised: 03/01/2014] [Accepted: 03/18/2014] [Indexed: 11/19/2022]
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32
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Basak S, Geng H, Jiang R. Rewiring global regulator cAMP receptor protein (CRP) to improve E. coli tolerance towards low pH. J Biotechnol 2014; 173:68-75. [PMID: 24452100 DOI: 10.1016/j.jbiotec.2014.01.015] [Citation(s) in RCA: 24] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/15/2013] [Revised: 01/07/2014] [Accepted: 01/11/2014] [Indexed: 11/19/2022]
Abstract
Bioprocesses such as production of organic acids or acid hydrolysis of bioresources during biofuel production often suffer limitations due to microbial sensitivity under acidic conditions. Approaches for improving the acid tolerance of these microbes have mainly focused on using metabolic engineering tools. Here, we tried to improve strain acidic tolerance from its transcription level, i.e. we adopted error-prone PCR method to engineer global regulator cAMP receptor protein (CRP) of Escherichia coli to improve its performance at low pH. The best mutant AcM1 was identified from random mutagenesis libraries based on its growth performance. AcM1 almost doubled (0.113h(-1)) the growth rate of the control (0.062h(-1)) at pH 4.24. It also demonstrated better thermotolerance than the control at 48°C, whose growth was completely inhibited at this temperature. Quantitative real time reverse transcription PCR results revealed a stress response overlap among low pH stress-, oxidative stress- and osmotic stress-related genes. The chief enzyme responsible for cell acid tolerance, glutamate decarboxylase, demonstrated over twofold activity in AcM1 compared to the control. Differential binding properties of AcM1 mutant CRP with Class-I, II, and III CRP-dependent promoters suggested that modifications to native CRP may lead to transcription profile changes. Hence, we believe that transcriptional engineering of global regulator CRP can provide a new strain engineering alternative for E. coli.
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Affiliation(s)
- Souvik Basak
- 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
| | - Rongrong Jiang
- School of Chemical & Biomedical Engineering, Nanyang Technological University, 62 Nanyang Drive, Singapore 637459, Singapore.
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33
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Fisher MA, Boyarskiy S, Yamada MR, Kong N, Bauer S, Tullman-Ercek D. Enhancing tolerance to short-chain alcohols by engineering the Escherichia coli AcrB efflux pump to secrete the non-native substrate n-butanol. ACS Synth Biol 2014; 3:30-40. [PMID: 23991711 DOI: 10.1021/sb400065q] [Citation(s) in RCA: 82] [Impact Index Per Article: 8.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022]
Abstract
The microbial conversion of sugars to fuels is a promising technology, but the byproducts of biomass pretreatment processes and the fuels themselves are often toxic at industrially relevant levels. One promising solution to these problems is to engineer efflux pumps to secrete fuels and inhibitory chemicals from the cell, increasing microbial tolerance and enabling higher fuel titer. Toward that end, we used a directed evolution strategy to generate variants of the Escherichia coli AcrB efflux pump that act on the non-native substrate n-butanol, enhancing growth rates of E. coli in the presence of this biofuel by up to 25%. Furthermore, these variants confer improved tolerance to isobutanol and straight-chain alcohols up to n-heptanol. Single amino acid changes in AcrB responsible for this phenotype were identified. We have also shown that both the chemical and genetic inactivation of pump activity eliminate the tolerance conferred by AcrB pump variants, supporting our assertion that the variants secrete the non-native substrates. This strategy can be applied to create an array of efflux pumps that modulate the intracellular concentrations of small molecules of interest to microbial fuel and chemical production.
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Affiliation(s)
- Michael A. Fisher
- Energy Biosciences
Institute, University of California Berkeley, 2151 Berkeley Way, Berkeley, California 94704, United States
| | - Sergey Boyarskiy
- Energy Biosciences
Institute, University of California Berkeley, 2151 Berkeley Way, Berkeley, California 94704, United States
- Department
of Bioengineering, University of California Berkeley, 306 Stanley
Hall MC #1762, Berkeley, California 94720, United States
| | - Masaki R. Yamada
- Department
of Chemical and Biomolecular Engineering, University of California Berkeley, 201 Gilman Hall, Berkeley, California 94720, United States
| | - Niwen Kong
- Department
of Molecular and Cell Biology, University of California Berkeley, 142 LSA #3200, Berkeley, California 94720, United States
| | - Stefan Bauer
- Energy Biosciences
Institute, University of California Berkeley, 2151 Berkeley Way, Berkeley, California 94704, United States
| | - Danielle Tullman-Ercek
- Energy Biosciences
Institute, University of California Berkeley, 2151 Berkeley Way, Berkeley, California 94704, United States
- Department
of Chemical and Biomolecular Engineering, University of California Berkeley, 201 Gilman Hall, Berkeley, California 94720, United States
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34
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Chen L, Wu L, Wang J, Zhang W. Butanol tolerance regulated by a two-component response regulator Slr1037 in photosynthetic Synechocystis sp. PCC 6803. BIOTECHNOLOGY FOR BIOFUELS 2014; 7:89. [PMID: 24932218 PMCID: PMC4057619 DOI: 10.1186/1754-6834-7-89] [Citation(s) in RCA: 28] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 12/23/2013] [Accepted: 05/27/2014] [Indexed: 05/03/2023]
Abstract
BACKGROUND Butanol production directly from CO2 in photosynthetic cyanobacteria is restricted by the high toxicity of butanol to the hosts. In previous studies, we have found that a few two-component signal transduction systems (TCSTSs) were differentially regulated in Synechocystis sp. PCC 6803 after butanol treatment. RESULTS To explore regulatory mechanisms of butanol tolerance, in this work, by constructing gene knockout mutants of the butanol-responsive TCSTS genes and conducting tolerance analysis, we uncovered that an orphan slr1037 gene encoding a novel response regulator was involved in butanol tolerance in Synechocystis. Interestingly, the ∆slr1037 mutant grew similarly to the wild type under several other stress conditions tested, which suggests that its regulation on butanol tolerance is specific. Using a quantitative iTRAQ LC-MS/MS proteomics approach coupled with real-time reverse transcription PCR, we further determined the possible butanol-tolerance regulon regulated by Slr1037. The results showed that, after slr1037 deletion, proteins involved in photosynthesis and glycolysis/gluconeogenesis of central metabolic processes, and glutaredoxin, peptide methionine sulfoxide reductase and glucosylglycerol-phosphate synthase with stress-responsive functions were down-regulated, suggesting that Slr1037 may exhibit regulation to a wide range of cellular functions in combating butanol stress. CONCLUSIONS The study provided a proteomic description of the putative butanol-tolerance regulon regulated by the slr1037 gene. As the first signal transduction protein identified directly related to butanol tolerance, response regulator Slr1037 could be a natural candidate for transcriptional engineering to improve butanol tolerance in Synechocystis.
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Affiliation(s)
- Lei Chen
- Laboratory of Synthetic Microbiology, 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
- Collaborative Innovation Center of Chemical Science and Engineering, Tianjin, P.R. China
| | - Lina Wu
- Laboratory of Synthetic Microbiology, 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
- Collaborative Innovation Center of Chemical Science and Engineering, Tianjin, P.R. China
| | - Jiangxin Wang
- Laboratory of Synthetic Microbiology, 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
- Collaborative Innovation Center of Chemical Science and Engineering, Tianjin, P.R. China
| | - Weiwen Zhang
- Laboratory of Synthetic Microbiology, 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
- Collaborative Innovation Center of Chemical Science and Engineering, Tianjin, P.R. China
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35
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Kang Z, Zhang C, Du G, Chen J. Metabolic Engineering of Escherichia coli for Production of 2-phenylethanol from Renewable Glucose. Appl Biochem Biotechnol 2013; 172:2012-21. [DOI: 10.1007/s12010-013-0659-3] [Citation(s) in RCA: 34] [Impact Index Per Article: 3.1] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/07/2013] [Accepted: 11/27/2013] [Indexed: 11/29/2022]
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36
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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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Engineering of transcriptional regulators enhances microbial stress tolerance. Biotechnol Adv 2013; 31:986-91. [DOI: 10.1016/j.biotechadv.2013.02.010] [Citation(s) in RCA: 53] [Impact Index Per Article: 4.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/30/2012] [Revised: 01/17/2013] [Accepted: 02/25/2013] [Indexed: 11/20/2022]
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38
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Chong H, Yeow J, Wang I, Song H, Jiang R. Improving acetate tolerance of Escherichia coli by rewiring its global regulator cAMP receptor protein (CRP). PLoS One 2013; 8:e77422. [PMID: 24124618 PMCID: PMC3790751 DOI: 10.1371/journal.pone.0077422] [Citation(s) in RCA: 25] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/16/2013] [Accepted: 09/10/2013] [Indexed: 11/18/2022] Open
Abstract
The presence of acetate exceeding 5 g/L is a major concern during E. coli fermentation due to its inhibitory effect on cell growth, thereby limiting high-density cell culture and recombinant protein production. Hence, engineered E. coli strains with enhanced acetate tolerance would be valuable for these bioprocesses. In this work, the acetate tolerance of E. coli was much improved by rewiring its global regulator cAMP receptor protein (CRP), which is reported to regulate 444 genes. Error-prone PCR method was employed to modify crp and the mutagenesis libraries (~3×10(6)) were subjected to M9 minimal medium supplemented with 5-10 g/L sodium acetate for selection. Mutant A2 (D138Y) was isolated and its growth rate in 15 g/L sodium acetate was found to be 0.083 h(-1), much higher than that of the control (0.016 h(-1)). Real-time PCR analysis via OpenArray(®) system revealed that over 400 CRP-regulated genes were differentially expressed in A2 with or without acetate stress, including those involved in the TCA cycle, phosphotransferase system, etc. Eight genes were chosen for overexpression and the overexpression of uxaB was found to lead to E. coli acetate sensitivity.
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Affiliation(s)
- Huiqing Chong
- School of Chemical and Biomedical Engineering, Nanyang Technological University, Singapore, Singapore
| | | | - Ivy Wang
- Life Technologies R&D, Singapore, Singapore
| | - Hao Song
- School of Chemical and Biomedical Engineering, Nanyang Technological University, Singapore, Singapore
| | - Rongrong Jiang
- School of Chemical and Biomedical Engineering, Nanyang Technological University, Singapore, Singapore
- * E-mail:
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39
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Wang J, Chen L, Tian X, Gao L, Niu X, Shi M, Zhang W. Global metabolomic and network analysis of Escherichia coli responses to exogenous biofuels. J Proteome Res 2013; 12:5302-12. [PMID: 24016299 DOI: 10.1021/pr400640u] [Citation(s) in RCA: 48] [Impact Index Per Article: 4.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/12/2023]
Abstract
Although synthetic biology progress has made it possible to produce various biofuels in more user-friendly hosts, such as Escherichia coli, the large-scale biofuel production in these non-native systems is still challenging, mostly due to the very low tolerance of these non-native hosts to the biofuel toxicity. To address the issues, in this study we determined the metabolic responses of E. coli induced by three major biofuel products, ethanol, butanol, and isobutanol, using a gas chromatography-mass spectrometry (GC-MS) approach. A metabolomic data set of 65 metabolites identified in all samples was then subjected to principal component analysis (PCA) to compare their effects and a weighted correlation network analysis (WGCNA) to identify the metabolic modules specifically responsive to each of the biofuel stresses, respectively. The PCA analysis showed that cellular responses caused by the biofuel stress were in general similar to aging cells at stationary phase, inconsistent with early studies showing a high degree of dissimilarity between metabolite responses during growth cessation as induced through stationary phases or through various environmental stress applications. The WGCNA analysis allowed identification of 2, 4, and 2 metabolic modules specifically associated with ethanol, butanol, and isobutanol treatments, respectively. The biofuel-associated modules included amino acids and osmoprotectants, such as isoleucine, valine, glycine, glutamate, and trehalose, suggesting amino acid metabolism and osmoregulation are among the key protection mechanisms against biofuel stresses in E. coli. Interestingly, no module was found associated with all three biofuel products, suggesting differential effects of each biofuel on E. coli. The findings enhanced our understanding of E. coli responses to exogenous biofuels and also demonstrated the effectiveness of the metabolomic and network analysis in identifying key targets for biofuel tolerance.
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Affiliation(s)
- Jiangxin Wang
- Laboratory of Synthetic Microbiology, School of Chemical Engineering & Technology, and Key Laboratory of Systems Bioengineering, Ministry of Education, Tianjin University , Tianjin 300072, P. R. China
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40
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Zhu H, Ren X, Wang J, Song Z, Shi M, Qiao J, Tian X, Liu J, Chen L, Zhang W. Integrated OMICS guided engineering of biofuel butanol-tolerance in photosynthetic Synechocystis sp. PCC 6803. BIOTECHNOLOGY FOR BIOFUELS 2013; 6:106. [PMID: 23883549 PMCID: PMC3726282 DOI: 10.1186/1754-6834-6-106] [Citation(s) in RCA: 49] [Impact Index Per Article: 4.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 04/06/2013] [Accepted: 07/23/2013] [Indexed: 05/03/2023]
Abstract
BACKGROUND Photosynthetic cyanobacteria have been recently proposed as a 'microbial factory' to produce butanol due to their capability to utilize solar energy and CO2 as the sole energy and carbon sources, respectively. However, to improve the productivity, one key issue needed to be addressed is the low tolerance of the photosynthetic hosts to butanol. RESULTS In this study, we first applied a quantitative transcriptomics approach with a next-generation RNA sequencing technology to identify gene targets relevant to butanol tolerance in a model cyanobacterium Synechocystis sp. PCC 6803. The results showed that 278 genes were induced by the butanol exposure at all three sampling points through the growth time course. Genes encoding heat-shock proteins, oxidative stress related proteins, transporters and proteins involved in common stress responses, were induced by butanol exposure. We then applied GC-MS based metabolomics analysis to determine the metabolic changes associated with the butanol exposure. The results showed that 46 out of 73 chemically classified metabolites were differentially regulated by butanol treatment. Notably, 3-phosphoglycerate, glycine, serine and urea related to general stress responses were elevated in butanol-treated cells. To validate the potential targets, we constructed gene knockout mutants for three selected gene targets. The comparative phenotypic analysis confirmed that these genes were involved in the butanol tolerance. CONCLUSION The integrated OMICS analysis provided a comprehensive view of the complicated molecular mechanisms employed by Synechocystis sp. PCC 6803 against butanol stress, and allowed identification of a series of potential gene candidates for tolerance engineering in cyanobacterium Synechocystis sp. PCC 6803.
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Affiliation(s)
- Hongji Zhu
- Laboratory of Synthetic Microbiology, School of Chemical Engineering & Technology, Tianjin University, Tianjin 300072, P.R. China
- Key Laboratory of Systems Bioengineering, Ministry of Education, Tianjin 300072, P.R. China
| | - Xiaoyue Ren
- Laboratory of Synthetic Microbiology, School of Chemical Engineering & Technology, Tianjin University, Tianjin 300072, P.R. China
- Key Laboratory of Systems Bioengineering, Ministry of Education, Tianjin 300072, P.R. China
| | - Jiangxin Wang
- Laboratory of Synthetic Microbiology, School of Chemical Engineering & Technology, Tianjin University, Tianjin 300072, P.R. China
- Key Laboratory of Systems Bioengineering, Ministry of Education, Tianjin 300072, P.R. China
| | - Zhongdi Song
- Laboratory of Synthetic Microbiology, School of Chemical Engineering & Technology, Tianjin University, Tianjin 300072, P.R. China
- Key Laboratory of Systems Bioengineering, Ministry of Education, Tianjin 300072, P.R. China
| | - Mengliang Shi
- Laboratory of Synthetic Microbiology, School of Chemical Engineering & Technology, Tianjin University, Tianjin 300072, P.R. China
- Key Laboratory of Systems Bioengineering, Ministry of Education, Tianjin 300072, P.R. China
| | - Jianjun Qiao
- Laboratory of Synthetic Microbiology, School of Chemical Engineering & Technology, Tianjin University, Tianjin 300072, P.R. China
- Key Laboratory of Systems Bioengineering, Ministry of Education, Tianjin 300072, P.R. China
| | - Xiaoxu Tian
- Laboratory of Synthetic Microbiology, School of Chemical Engineering & Technology, Tianjin University, Tianjin 300072, P.R. China
- Key Laboratory of Systems Bioengineering, Ministry of Education, Tianjin 300072, P.R. China
| | - Jie Liu
- Laboratory of Synthetic Microbiology, School of Chemical Engineering & Technology, Tianjin University, Tianjin 300072, P.R. China
- Key Laboratory of Systems Bioengineering, Ministry of Education, Tianjin 300072, P.R. China
| | - Lei Chen
- Laboratory of Synthetic Microbiology, School of Chemical Engineering & Technology, Tianjin University, Tianjin 300072, P.R. China
- Key Laboratory of Systems Bioengineering, Ministry of Education, Tianjin 300072, P.R. China
| | - Weiwen Zhang
- Laboratory of Synthetic Microbiology, School of Chemical Engineering & Technology, Tianjin University, Tianjin 300072, P.R. China
- Key Laboratory of Systems Bioengineering, Ministry of Education, Tianjin 300072, P.R. China
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Marcheschi RJ, Gronenberg LS, Liao JC. Protein engineering for metabolic engineering: current and next-generation tools. Biotechnol J 2013; 8:545-55. [PMID: 23589443 DOI: 10.1002/biot.201200371] [Citation(s) in RCA: 35] [Impact Index Per Article: 3.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/20/2012] [Revised: 03/07/2013] [Accepted: 03/20/2013] [Indexed: 11/10/2022]
Abstract
Protein engineering in the context of metabolic engineering is increasingly important to the field of industrial biotechnology. As the demand for biologically produced food, fuels, chemicals, food additives, and pharmaceuticals continues to grow, the ability to design and modify proteins to accomplish new functions will be required to meet the high productivity demands for the metabolism of engineered organisms. We review advances in selecting, modeling, and engineering proteins to improve or alter their activity. Some of the methods have only recently been developed for general use and are just beginning to find greater application in the metabolic engineering community. We also discuss methods of generating random and targeted diversity in proteins to generate mutant libraries for analysis. Recent uses of these techniques to alter cofactor use; produce non-natural amino acids, alcohols, and carboxylic acids; and alter organism phenotypes are presented and discussed as examples of the successful engineering of proteins for metabolic engineering purposes.
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Affiliation(s)
- Ryan J Marcheschi
- Department of Chemical and Biomolecular Engineering, University of California, Los Angeles, CA, USA
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42
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Production of long-chain hydroxy fatty acids by microbial conversion. Appl Microbiol Biotechnol 2013; 97:3323-31. [PMID: 23494626 DOI: 10.1007/s00253-013-4815-z] [Citation(s) in RCA: 35] [Impact Index Per Article: 3.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/26/2012] [Revised: 02/24/2013] [Accepted: 02/26/2013] [Indexed: 10/27/2022]
Abstract
Hydroxy fatty acids (HFAs) are very important chemicals for versatile applications in biodegradable polymer materials and cosmetic and pharmaceutical industries. They are difficult to be synthesized via chemical routes due to the inertness of the fatty acyl chain. In contrast, these fatty acids make up a major class of natural products widespread among bacteria, yeasts, and fungi. A number of microorganisms capable of producing HFAs from fatty acids or vegetable oils have been reported. Therefore, HFAs could be produced by biotechnological strategies, especially by microbial conversion processes. Microorganisms could oxidize fatty acids either at the terminal carbon or inside the acyl chain to produce various HFAs, including α-HFAs, β-HFAs, mid-position HFAs, ω-HFAs, di-HFAs, and tri-HFAs. The enzymes and their encoded genes responsible for the hydroxylation of the carbon chain have been identified and characterized during the past few years. The involved microbes and catalytic mechanisms for the production of different types of HFAs are systematically demonstrated in this review. It provides a better view of HFA biosynthesis and lays the foundation for further industrial production.
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Skretas G, Kolisis FN. Combinatorial approaches for inverse metabolic engineering applications. Comput Struct Biotechnol J 2013; 3:e201210021. [PMID: 24688681 PMCID: PMC3962077 DOI: 10.5936/csbj.201210021] [Citation(s) in RCA: 13] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/02/2012] [Revised: 02/11/2013] [Accepted: 02/17/2013] [Indexed: 11/22/2022] Open
Abstract
Traditional metabolic engineering analyzes biosynthetic and physiological pathways, identifies bottlenecks, and makes targeted genetic modifications with the ultimate goal of increasing the production of high-value products in living cells. Such efforts have led to the development of a variety of organisms with industrially relevant properties. However, there are a number of cellular phenotypes important for research and the industry for which the rational selection of cellular targets for modification is not easy or possible. In these cases, strain engineering can be alternatively carried out using “inverse metabolic engineering”, an approach that first generates genetic diversity by subjecting a population of cells to a particular mutagenic process, and then utilizes genetic screens or selections to identify the clones exhibiting the desired phenotype. Given the availability of an appropriate screen for a particular property, the success of inverse metabolic engineering efforts usually depends on the level and quality of genetic diversity which can be generated. Here, we review classic and recently developed combinatorial approaches for creating such genetic diversity and discuss the use of these methodologies in inverse metabolic engineering applications.
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Affiliation(s)
- Georgios Skretas
- Institute of Biology, Medicinal Chemistry and Biotechnology, National Hellenic Research Foundation, Athens, Greece
| | - Fragiskos N Kolisis
- Biotechnology Laboratory, School of Chemical Engineering, National Technical University of Athens - Zografou Campus, Athens, Greece
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Chong H, Huang L, Yeow J, Wang I, Zhang H, Song H, Jiang R. Improving ethanol tolerance of Escherichia coli by rewiring its global regulator cAMP receptor protein (CRP). PLoS One 2013; 8:e57628. [PMID: 23469036 PMCID: PMC3585226 DOI: 10.1371/journal.pone.0057628] [Citation(s) in RCA: 44] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/20/2012] [Accepted: 01/21/2013] [Indexed: 11/19/2022] Open
Abstract
A major challenge in bioethanol fermentation is the low tolerance of the microbial host towards the end product bioethanol. Here we report to improve the ethanol tolerance of E. coli from the transcriptional level by engineering its global transcription factor cAMP receptor protein (CRP), which is known to regulate over 400 genes in E. coli. Three ethanol tolerant CRP mutants (E1- E3) were identified from error-prone PCR libraries. The best ethanol-tolerant strain E2 (M59T) had the growth rate of 0.08 h(-1) in 62 g/L ethanol, higher than that of the control at 0.06 h(-1). The M59T mutation was then integrated into the genome to create variant iE2. When exposed to 150 g/l ethanol, the survival of iE2 after 15 min was about 12%, while that of BW25113 was <0.01%. Quantitative real-time reverse transcription PCR analysis (RT-PCR) on 444 CRP-regulated genes using OpenArray® technology revealed that 203 genes were differentially expressed in iE2 in the absence of ethanol, whereas 92 displayed differential expression when facing ethanol stress. These genes belong to various functional groups, including central intermediary metabolism (aceE, acnA, sdhD, sucA), iron ion transport (entH, entD, fecA, fecB), and general stress response (osmY, rpoS). Six up-regulated and twelve down-regulated common genes were found in both iE2 and E2 under ethanol stress, whereas over one hundred common genes showed differential expression in the absence of ethanol. Based on the RT-PCR results, entA, marA or bhsA was knocked out in iE2 and the resulting strains became more sensitive towards ethanol.
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Affiliation(s)
- Huiqing Chong
- School of Chemical & Biomedical Engineering, Nanyang Technological University, Singapore
| | - Lei Huang
- Institute of Biological Engineering, Department of Chemical and Biological Engineering, Zhejiang University, Hangzhou, P. R. China
| | - Jianwei Yeow
- System Engineering, Life Technologies, Singapore
| | - Ivy Wang
- System Engineering, Life Technologies, Singapore
| | - Hongfang Zhang
- School of Chemical & Biomedical Engineering, Nanyang Technological University, Singapore
| | - Hao Song
- School of Chemical & Biomedical Engineering, Nanyang Technological University, Singapore
| | - Rongrong Jiang
- School of Chemical & Biomedical Engineering, Nanyang Technological University, Singapore
- * E-mail:
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45
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Basak S, Jiang R. Enhancing E. coli tolerance towards oxidative stress via engineering its global regulator cAMP receptor protein (CRP). PLoS One 2012; 7:e51179. [PMID: 23251448 PMCID: PMC3522674 DOI: 10.1371/journal.pone.0051179] [Citation(s) in RCA: 44] [Impact Index Per Article: 3.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/19/2012] [Accepted: 10/30/2012] [Indexed: 12/11/2022] Open
Abstract
Oxidative damage to microbial hosts often occurs under stressful conditions during bioprocessing. Classical strain engineering approaches are usually both time-consuming and labor intensive. Here, we aim to improve E. coli performance under oxidative stress via engineering its global regulator cAMP receptor protein (CRP), which can directly or indirectly regulate redox-sensing regulators SoxR and OxyR, and other ~400 genes in E. coli. Error-prone PCR technique was employed to introduce modifications to CRP, and three mutants (OM1~OM3) were identified with improved tolerance via H(2)O(2) enrichment selection. The best mutant OM3 could grow in 12 mM H(2)O(2) with the growth rate of 0.6 h(-1), whereas the growth of wild type was completely inhibited at this H(2)O(2) concentration. OM3 also elicited enhanced thermotolerance at 48°C as well as resistance against cumene hydroperoxide. The investigation about intracellular reactive oxygen species (ROS), which determines cell viability, indicated that the accumulation of ROS in OM3 was always lower than in WT with or without H(2)O(2) treatment. Genome-wide DNA microarray analysis has shown not only CRP-regulated genes have demonstrated great transcriptional level changes (up to 8.9-fold), but also RpoS- and OxyR-regulated genes (up to 7.7-fold). qRT-PCR data and enzyme activity assay suggested that catalase (katE) could be a major antioxidant enzyme in OM3 instead of alkyl hydroperoxide reductase or superoxide dismutase. To our knowledge, this is the first work on improving E. coli oxidative stress resistance by reframing its transcription machinery through its native global regulator. The positive outcome of this approach may suggest that engineering CRP can be successfully implemented as an efficient strain engineering alternative for E. coli.
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Affiliation(s)
- Souvik Basak
- School of Chemical & Biomedical Engineering, Nanyang Technological University, Singapore, Singapore
| | - Rongrong Jiang
- School of Chemical & Biomedical Engineering, Nanyang Technological University, Singapore, Singapore
- * E-mail:
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46
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Error-prone PCR of global transcription factor cyclic AMP receptor protein for enhanced organic solvent (toluene) tolerance. Process Biochem 2012. [DOI: 10.1016/j.procbio.2012.08.006] [Citation(s) in RCA: 13] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 11/16/2022]
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Tian X, Chen L, Wang J, Qiao J, Zhang W. Quantitative proteomics reveals dynamic responses of Synechocystis sp. PCC 6803 to next-generation biofuel butanol. J Proteomics 2012; 78:326-45. [PMID: 23079071 DOI: 10.1016/j.jprot.2012.10.002] [Citation(s) in RCA: 75] [Impact Index Per Article: 6.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/22/2012] [Revised: 10/01/2012] [Accepted: 10/04/2012] [Indexed: 01/04/2023]
Abstract
Butanol is a promising biofuel, and recent metabolic engineering efforts have demonstrated the use of photosynthetic cyanobacterial hosts for its production. However, cyanobacteria have very low tolerance to butanol, limiting the economic viability of butanol production from these renewable producing systems. The existing knowledge of molecular mechanism involved in butanol tolerance in cyanobacteria is very limited. To build a foundation necessary to engineer robust butanol-producing cyanobacterial hosts, in this study, the responses of Synechocystis PCC 6803 to butanol were investigated using a quantitative proteomics approach with iTRAQ - LC-MS/MS technologies. The resulting high-quality dataset consisted of 25,347 peptides corresponding to 1452 unique proteins, a coverage of approximately 40% of the predicted proteins in Synechocystis. Comparative quantification of protein abundances led to the identification of 303 differentially regulated proteins by butanol. Annotation and GO term enrichment analysis showed that multiple biological processes were regulated, suggesting that Synechocystis probably employed multiple and synergistic resistance mechanisms in dealing with butanol stress. Notably, the analysis revealed the induction of heat-shock protein and transporters, along with modification of cell membrane and envelope were the major protection mechanisms against butanol. A conceptual cellular model of Synechocystis PCC 6803 responses to butanol stress was constructed to illustrate the putative molecular mechanisms employed to defend against butanol stress.
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Affiliation(s)
- Xiaoxu Tian
- School of Chemical Engineering & Technology, Tianjin University, Tianjin 300072, PR China
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