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Cao L, Gao Y, Wang XZ, Shu GY, Hu YN, Xie ZP, Cui W, Guo XP, Zhou X. A Series of Efficient Umbrella Modeling Strategies to Track Irradiation-Mutation Strains Improving Butyric Acid Production From the Pre-development Earlier Stage Point of View. Front Bioeng Biotechnol 2021; 9:609345. [PMID: 34222207 PMCID: PMC8242359 DOI: 10.3389/fbioe.2021.609345] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/23/2020] [Accepted: 05/10/2021] [Indexed: 11/13/2022] Open
Abstract
Clostridium tyrobutyricum (C. tyrobutyricum) is a fermentation strain used to produce butyric acid. A promising new biofuel, n-butanol, can be produced by catalysis of butyrate, which can be obtained through microbial fermentation. Butyric acid has various uses in food additives and flavor agents, antiseptic substances, drug formulations, and fragrances. Its use as a food flavoring has been approved by the European Union, and it has therefore been listed on the EU Lists of Flavorings. As butyric acid fermentation is a cost-efficient process, butyric acid is an attractive feedstock for various biofuels and food commercialization products. 12C6+ irradiation has advantages over conventional mutation methods for fermentation production due to its dosage conformity and excellent biological availability. Nevertheless, the effects of these heavy-ion irradiations on the specific productiveness of C. tyrobutyricum are still uncertain. We developed non-structured mathematical models to represent the heavy-ion irradiation of C. tyrobutyricum in biofermentation reactors. The kinetic models reflect various fermentation features of the mutants, including the mutant strain growth model, butyric acid formation model, and medium consumption model. The models were constructed based on the Markov chain Monte Carlo model and logistic regression. Models were verified using experimental data in response to different initial glucose concentrations (0-180 g/L). The parameters of fixed proposals are applied in the various fermentation stages. Predictions of these models were in accordance well with the results of fermentation assays. The maximum butyric acid production was 56.3 g/L. Our study provides reliable information for increasing butyric acid production and for evaluating the feasibility of using mutant strains of C. tyrobutyricum at the pre-development phase.
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Affiliation(s)
- Li Cao
- College of Life Sciences and Engineering, Hexi University, Zhangye, China
| | - Yue Gao
- Institute of Modern Physics, Chinese Academy of Sciences, Lanzhou, China.,College of Life Science, University of Chinese Academy of Sciences, Beijing, China
| | - Xue-Zhen Wang
- College of Life Sciences and Engineering, Hexi University, Zhangye, China
| | - Guang-Yuan Shu
- College of Life Sciences and Engineering, Hexi University, Zhangye, China
| | - Ya-Nan Hu
- College of Life Sciences and Engineering, Hexi University, Zhangye, China
| | - Zong-Ping Xie
- College of Life Sciences and Engineering, Hexi University, Zhangye, China
| | - Wei Cui
- College of Life Sciences and Engineering, Hexi University, Zhangye, China
| | - Xiao-Peng Guo
- Institute of Modern Physics, Chinese Academy of Sciences, Lanzhou, China.,College of Life Science, University of Chinese Academy of Sciences, Beijing, China
| | - Xiang Zhou
- Institute of Modern Physics, Chinese Academy of Sciences, Lanzhou, China.,College of Life Science, University of Chinese Academy of Sciences, Beijing, China
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Jawed K, Abdelaal AS, Koffas MAG, Yazdani SS. Improved Butanol Production Using FASII Pathway in E. coli. ACS Synth Biol 2020; 9:2390-2398. [PMID: 32813973 DOI: 10.1021/acssynbio.0c00154] [Citation(s) in RCA: 8] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/17/2023]
Abstract
n-Butanol is often considered a potential substitute for gasoline due to its physicochemical properties being closely related to those of gasoline. In this study, we extend our earlier work to convert endogenously producing butyrate via the FASII pathway using thioesterase TesBT to its corresponding alcohol, i.e., butanol. We first assembled pathway genes, i.e., car encoding carboxylic acid reductase from Mycobacterium marinum, sfp encoding phosphopantetheinyl transferase from Bacillus subtilis, and adh2 encoding alcohol dehydrogenase from S. cerevisiae, responsible for bioconversion of butyrate to butanol in three different configurations (Operon, Pseudo-Operon, and Monocistronic) to achieve optimum expression of each gene and compared with the clostridial solventogenic pathway for in vivo conversion of butyrate to butanol under aerobic conditions. An E. coli strain harboring car, sfp, and adh2 in pseudo-operon configuration was able to convert butyrate to butanol with 100% bioconversion efficiency when supplemented with 1 g/L of butyrate. Further, co-cultivation of an upstream strain (butyrate-producing) with a downstream strain (butyrate to butanol converting) at different inoculation ratios was investigated, and an optimized ratio of 1:4 (upstream strain: downstream strain) was found to produce ∼2 g/L butanol under fed-batch fermentation. Further, a mono-cultivation approach was applied by transforming a plasmid harboring tesBT gene into the downstream strain. This approach produced 0.42 g/L in a test tube and ∼2.9 g/L butanol under fed-batch fermentation. This is the first report where both mono- and co-cultivation approaches were tested and compared for butanol production, and butanol titers achieved using both strategies are the highest reported values in recombinant E. coli utilizing FASII pathway.
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Affiliation(s)
- Kamran Jawed
- Microbial Engineering Group, International Centre for Genetic Engineering and Biotechnology, 110067 New Delhi, India
- Department of Chemical and Biological Engineering, Rensselaer Polytechnic Institute, Troy, New York 12180, United States
| | - Ali Samy Abdelaal
- Microbial Engineering Group, International Centre for Genetic Engineering and Biotechnology, 110067 New Delhi, India
- Department of Genetics, Faculty of Agriculture, Damietta University, 34511 Damietta, Egypt
| | - Mattheos A. G. Koffas
- Department of Chemical and Biological Engineering, Rensselaer Polytechnic Institute, Troy, New York 12180, United States
- Department of Biological Sciences, Rensselaer Polytechnic Institute, Troy, New York 12180, United States
| | - Syed Shams Yazdani
- Microbial Engineering Group, International Centre for Genetic Engineering and Biotechnology, 110067 New Delhi, India
- DBT-ICGEB Centre for Advanced Bioenergy Research, International Centre for Genetic Engineering and Biotechnology, 110067 New Delhi, India
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Efficient, Simple Production of Corresponding Alcohols from Supplemented C2-C8 Carboxylic Acids in Escherichia coli Using Acyl-CoA Transferase from Megasphaera hexanoica. BIOTECHNOL BIOPROC E 2020. [DOI: 10.1007/s12257-020-0163-x] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/12/2022]
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Nawab S, Wang N, Ma X, Huo YX. Genetic engineering of non-native hosts for 1-butanol production and its challenges: a review. Microb Cell Fact 2020; 19:79. [PMID: 32220254 PMCID: PMC7099781 DOI: 10.1186/s12934-020-01337-w] [Citation(s) in RCA: 14] [Impact Index Per Article: 3.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/30/2019] [Accepted: 03/18/2020] [Indexed: 12/28/2022] Open
Abstract
BACKGROUND Owing to the increase in energy consumption, fossil fuel resources are gradually depleting which has led to the growing environmental concerns; therefore, scientists are being urged to produce sustainable and ecofriendly fuels. Thus, there is a growing interest in the generation of biofuels from renewable energy resources using microbial fermentation. MAIN TEXT Butanol is a promising biofuel that can substitute for gasoline; unfortunately, natural microorganisms pose challenges for the economical production of 1-butanol at an industrial scale. The availability of genetic and molecular tools to engineer existing native pathways or create synthetic pathways have made non-native hosts a good choice for the production of 1-butanol from renewable resources. Non-native hosts have several distinct advantages, including using of cost-efficient feedstock, solvent tolerant and reduction of contamination risk. Therefore, engineering non-native hosts to produce biofuels is a promising approach towards achieving sustainability. This paper reviews the currently employed strategies and synthetic biology approaches used to produce 1-butanol in non-native hosts over the past few years. In addition, current challenges faced in using non-native hosts and the possible solutions that can help improve 1-butanol production are also discussed. CONCLUSION Non-native organisms have the potential to realize commercial production of 1- butanol from renewable resources. Future research should focus on substrate utilization, cofactor imbalance, and promoter selection to boost 1-butanol production in non-native hosts. Moreover, the application of robust genetic engineering approaches is required for metabolic engineering of microorganisms to make them industrially feasible for 1-butanol production.
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Affiliation(s)
- Said Nawab
- Key Laboratory of Molecular Medicine and Biotherapy, School of Life Science, Beijing Institute of Technology, 5 South Zhongguancun Street, Haidian District, Beijing, 100081, People's Republic of China
| | - Ning Wang
- Key Laboratory of Molecular Medicine and Biotherapy, School of Life Science, Beijing Institute of Technology, 5 South Zhongguancun Street, Haidian District, Beijing, 100081, People's Republic of China.
| | - Xiaoyan Ma
- Key Laboratory of Molecular Medicine and Biotherapy, School of Life Science, Beijing Institute of Technology, 5 South Zhongguancun Street, Haidian District, Beijing, 100081, People's Republic of China.
| | - Yi-Xin Huo
- Key Laboratory of Molecular Medicine and Biotherapy, School of Life Science, Beijing Institute of Technology, 5 South Zhongguancun Street, Haidian District, Beijing, 100081, People's Republic of China
- Biology Institute, Shandong Province Key Laboratory for Biosensors, Qilu University of Technology (Shandong Academy of Sciences), Jinan, 250103, China
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Abdelaal AS, Jawed K, Yazdani SS. CRISPR/Cas9-mediated engineering of Escherichia coli for n-butanol production from xylose in defined medium. J Ind Microbiol Biotechnol 2019; 46:965-975. [PMID: 30982114 DOI: 10.1007/s10295-019-02180-8] [Citation(s) in RCA: 21] [Impact Index Per Article: 4.2] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/22/2018] [Accepted: 04/09/2019] [Indexed: 01/14/2023]
Abstract
Butanol production from agricultural residues is the most promising alternative for fossil fuels. To reach the economic viability of biobutanol production, both glucose and xylose should be utilized and converted into butanol. Here, we engineered a dual-operon-based synthetic pathway in the genome of E. coli MG1655 to produce n-butanol using CRISPR/Cas9 technology. Further deletion of competing pathway followed by fed-batch cultivation of the engineered strain in a bioreactor with glucose-containing complex medium yielded 5.4 g/L n-butanol along with pyruvate as major co-product, indicating a redox imbalance. To ferment xylose into butanol in redox-balanced manner, we selected SSK42, an ethanologenic E. coli strain engineered and evolved in our laboratory to produce ethanol from xylose, for integrating synthetic butanol cassette in its genome via CRISPR/Cas9 after deleting the gene responsible for endogenous ethanol production. The engineered plasmid- and marker-free strain, ASA02, produced 4.32 g/L butanol in fed-batch fermentation in completely defined AM1-xylose medium.
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Affiliation(s)
- Ali Samy Abdelaal
- Microbial Engineering Group, International Centre for Genetic Engineering and Biotechnology, New Delhi, India
- Department of Genetics, Faculty of Agriculture, Damietta University, Damietta, Egypt
| | - Kamran Jawed
- Microbial Engineering Group, International Centre for Genetic Engineering and Biotechnology, New Delhi, India
| | - Syed Shams Yazdani
- Microbial Engineering Group, International Centre for Genetic Engineering and Biotechnology, New Delhi, India.
- DBT-ICGEB Centre for Advanced Bioenergy Research, International Centre for Genetic Engineering and Biotechnology, New Delhi, India.
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Fatma Z, Hartman H, Poolman MG, Fell DA, Srivastava S, Shakeel T, Yazdani SS. Model-assisted metabolic engineering of Escherichia coli for long chain alkane and alcohol production. Metab Eng 2018; 46:1-12. [DOI: 10.1016/j.ymben.2018.01.002] [Citation(s) in RCA: 39] [Impact Index Per Article: 6.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/22/2017] [Revised: 12/13/2017] [Accepted: 01/29/2018] [Indexed: 12/19/2022]
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Sangavai C, Chellapandi P. Amino acid catabolism-directed biofuel production in Clostridium sticklandii: An insight into model-driven systems engineering. ACTA ACUST UNITED AC 2017; 16:32-43. [PMID: 29167757 PMCID: PMC5686429 DOI: 10.1016/j.btre.2017.11.002] [Citation(s) in RCA: 13] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/30/2017] [Revised: 10/17/2017] [Accepted: 11/03/2017] [Indexed: 01/01/2023]
Abstract
Model-driven systems engineering has been more fascinating process for microbial biofuel production. Clostridium sticklandii is a potential strain for the solventogenesis and acidogenesis. The present review provides an insight for the protein catabolism-directed biofuel production.
Model-driven systems engineering has been more fascinating process for the microbial production of biofuel and bio-refineries in chemical and pharmaceutical industries. Genome-scale modeling and simulations have been guided for metabolic engineering of Clostridium species for the production of organic solvents and organic acids. Among them, Clostridium sticklandii is one of the potential organisms to be exploited as a microbial cell factory for biofuel production. It is a hyper-ammonia producing bacterium and is able to catabolize amino acids as important carbon and energy sources via Stickland reactions and the development of the specific pathways. Current genomic and metabolic aspects of this bacterium are comprehensively reviewed herein, which provided information for learning about protein catabolism-directed biofuel production. It has a metabolic potential to drive energy and direct solventogenesis as well as acidogenesis from protein catabolism. It produces by-products such as ethanol, acetate, n-butanol, n-butyrate and hydrogen from amino acid catabolism. Model-driven systems engineering of this organism would improve the performance of the industrial sectors and enhance the industrial economy by using protein-based waste in environment-friendly ways.
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Affiliation(s)
- C Sangavai
- Molecular Systems Engineering Lab, Department of Bioinformatics, School of Life Sciences, Bharathidasan University, Tiruchirappalli, 620 024, Tamil Nadu, India
| | - P Chellapandi
- Molecular Systems Engineering Lab, Department of Bioinformatics, School of Life Sciences, Bharathidasan University, Tiruchirappalli, 620 024, Tamil Nadu, India
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Identification of long chain specific aldehyde reductase and its use in enhanced fatty alcohol production in E. coli. Metab Eng 2016; 37:35-45. [DOI: 10.1016/j.ymben.2016.04.003] [Citation(s) in RCA: 38] [Impact Index Per Article: 4.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/13/2015] [Revised: 04/09/2016] [Accepted: 04/25/2016] [Indexed: 11/23/2022]
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9
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Zheng Y, Li L, Liu Q, Zhang H, Cao Y, Xian M, Liu H. High-specificity synthesis of novel monomers by remodeled alcohol hydroxylase. BMC Biotechnol 2016; 16:61. [PMID: 27557638 PMCID: PMC4995789 DOI: 10.1186/s12896-016-0291-8] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/08/2016] [Accepted: 08/10/2016] [Indexed: 11/10/2022] Open
Abstract
BACKGROUND Diols are important monomers for the production of plastics and polyurethanes, which are widely used in our daily life. The medium-chain diols with one hydroxyl group at its subterminal end are able to confer more flexibility upon the synthesized materials. But unfortunately, this type of diols has not been synthesized so far. The strong need for advanced materials impelled us to develop a new strategy for the production of these novel diols. In this study, we use the remodeled P450BM3 for high-specificity production of 1,7-decanediol. RESULTS The native P450BM3 was capable of converting medium-chain alcohols into corresponding α, ω1-, α, ω2- and α, ω3-diols, with each of them accounting for about one third of the total diols, but it exhibited a little or no activity on the short-chain alcohols. Greatly improved regiospecificity of alcohol hydroxylation was obtained by laboratory evolution of P450BM3. After substitution of 12 amino acid residues (J2-F87A), the ratio of 1,7-decanediol (ω-3 hydroxylation) to total decanediols increased to 86.8 % from 34.0 %. Structure modeling and site-directed mutagenesis demonstrated that the heme end residues such as Ala(78), Phe(87) and Arg(255) play a key role in controlling the regioselectivity of the alcohol hydroxylation, while the residues at the mouth of substrate binding site is not responsible for the regioselectivity. CONCLUSIONS Herein we employ an engineered P450BM3 for the first time to enable the high-specificity biosynthesis of 1,7-decanediol, which is a promising monomer for the development of advanced materials. Several key amino acid residues that control the regioselectivity of alcohol hydroxylation were identified, providing some new insights into how to improve the regiospecificity of alcohol hydroxylation. This report not only provides a good strategy for the biosynthesis of 1,7-decanediol, but also gives a promising approach for the production of other useful diols.
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Affiliation(s)
- Yanning Zheng
- CAS Key Laboratory of Biobased Materials, Qingdao Institute of Bioenergy and Bioprocess Technology, Chinese Academy of Sciences, No.189 Songling Road, Laoshan District, Qingdao, 266101, China
| | - Lingling Li
- CAS Key Laboratory of Biobased Materials, Qingdao Institute of Bioenergy and Bioprocess Technology, Chinese Academy of Sciences, No.189 Songling Road, Laoshan District, Qingdao, 266101, China.,College of Food Science, Sichuan Agricultural University, Yaan, 625014, China
| | - Qiang Liu
- CAS Key Laboratory of Biobased Materials, Qingdao Institute of Bioenergy and Bioprocess Technology, Chinese Academy of Sciences, No.189 Songling Road, Laoshan District, Qingdao, 266101, China.,College of Food Science, Sichuan Agricultural University, Yaan, 625014, China
| | - Haibo Zhang
- CAS Key Laboratory of Biobased Materials, Qingdao Institute of Bioenergy and Bioprocess Technology, Chinese Academy of Sciences, No.189 Songling Road, Laoshan District, Qingdao, 266101, China
| | - Yujin Cao
- CAS Key Laboratory of Biobased Materials, Qingdao Institute of Bioenergy and Bioprocess Technology, Chinese Academy of Sciences, No.189 Songling Road, Laoshan District, Qingdao, 266101, China
| | - Mo Xian
- CAS Key Laboratory of Biobased Materials, Qingdao Institute of Bioenergy and Bioprocess Technology, Chinese Academy of Sciences, No.189 Songling Road, Laoshan District, Qingdao, 266101, China.
| | - Huizhou Liu
- CAS Key Laboratory of Biobased Materials, Qingdao Institute of Bioenergy and Bioprocess Technology, Chinese Academy of Sciences, No.189 Songling Road, Laoshan District, Qingdao, 266101, China.
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Engineered Production of Short Chain Fatty Acid in Escherichia coli Using Fatty Acid Synthesis Pathway. PLoS One 2016; 11:e0160035. [PMID: 27466817 PMCID: PMC4965127 DOI: 10.1371/journal.pone.0160035] [Citation(s) in RCA: 41] [Impact Index Per Article: 5.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/20/2016] [Accepted: 07/12/2016] [Indexed: 11/19/2022] Open
Abstract
Short-chain fatty acids (SCFAs), such as butyric acid, have a broad range of applications in chemical and fuel industries. Worldwide demand of sustainable fuels and chemicals has encouraged researchers for microbial synthesis of SCFAs. In this study we compared three thioesterases, i.e., TesAT from Anaerococcus tetradius, TesBF from Bryantella formatexigens and TesBT from Bacteroides thetaiotaomicron, for production of SCFAs in Escherichia coli utilizing native fatty acid synthesis (FASII) pathway and modulated the genetic and bioprocess parameters to improve its yield and productivity. E. coli strain expressing tesBT gene yielded maximum butyric acid titer at 1.46 g L-1, followed by tesBF at 0.85 g L-1 and tesAT at 0.12 g L-1. The titer of butyric acid varied significantly depending upon the plasmid copy number and strain genotype. The modulation of genetic factors that are known to influence long chain fatty acid production, such as deletion of the fadD and fadE that initiates the fatty acid degradation cycle and overexpression of fadR that is a global transcriptional activator of fatty acid biosynthesis and repressor of degradation cycle, did not improve the butyric acid titer significantly. Use of chemical inhibitor cerulenin, which restricts the fatty acid elongation cycle, increased the butyric acid titer by 1.7-fold in case of TesBF, while it had adverse impact in case of TesBT. In vitro enzyme assay indicated that cerulenin also inhibited short chain specific thioesterase, though inhibitory concentration varied according to the type of thioesterase used. Further process optimization followed by fed-batch cultivation under phosphorous limited condition led to production of 14.3 g L-1 butyric acid and 17.5 g L-1 total free fatty acid at 28% of theoretical yield. This study expands our understanding of SCFAs production in E. coli through FASII pathway and highlights role of genetic and process optimization to enhance the desired product.
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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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Saini M, Hong Chen M, Chiang CJ, Chao YP. Potential production platform of n-butanol in Escherichia coli. Metab Eng 2014; 27:76-82. [PMID: 25461833 DOI: 10.1016/j.ymben.2014.11.001] [Citation(s) in RCA: 67] [Impact Index Per Article: 6.7] [Reference Citation Analysis] [Abstract] [Key Words] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/29/2014] [Revised: 10/21/2014] [Accepted: 11/07/2014] [Indexed: 10/24/2022]
Abstract
We proposed a potential production platform of n-butanol in Escherichia coli. First, a butyrate-conversion strain was developed by removal of undesired genes and recruiting endogenous atoDA and Clostridium adhE2. Consequently, this E. coli strain grown on the M9 mineral salt with yeast extract (M9Y) was shown to produce 6.2g/L n-butanol from supplemented butyrate at 36h. The molar conversion yield of n-butanol on butyrate reaches 92%. Moreover, the production platform was advanced by additional inclusion of a butyrate-producing strain. This strain was equipped with a pathway comprising atoDA and heterologous genes for the synthesis of butyrate. Without butyrate, the butyrate-conversion and the butyrate-producing strains were co-cultured in M9Y medium and produced 5.5g/L n-butanol from glucose at 24h. The production yield on glucose accounts for 69% of the theoretical yield. Overall, it indicates a promise of the developed platform for n-butanol production in E. coli.
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Affiliation(s)
- Mukesh Saini
- Department of Chemical Engineering, Feng Chia University, 100 Wenhwa Road, Taichung 40724, Taiwan
| | - Min Hong Chen
- Department of Chemical Engineering, Feng Chia University, 100 Wenhwa Road, Taichung 40724, Taiwan
| | - Chung-Jen Chiang
- Department of Medical Laboratory Science and Biotechnology, China Medical University, No. 91, Hsueh-Shih Road, Taichung 40402, Taiwan.
| | - Yun-Peng Chao
- Department of Chemical Engineering, Feng Chia University, 100 Wenhwa Road, Taichung 40724, Taiwan; Department of Health and Nutrition Biotechnology, Asia University, Taichung 41354, Taiwan; Department of Medical Research, China Medical University Hospital, Taichung 40447, Taiwan.
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13
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Banka AL, Guralp SA, Gulari E. Secretory expression and characterization of two hemicellulases, xylanase, and β-xylosidase, isolated from Bacillus subtilis M015. Appl Biochem Biotechnol 2014; 174:2702-10. [PMID: 25224913 PMCID: PMC4237932 DOI: 10.1007/s12010-014-1219-1] [Citation(s) in RCA: 19] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/31/2014] [Accepted: 09/02/2014] [Indexed: 11/23/2022]
Abstract
Microbial hydrolysis of lignocellulosic biomass is becoming increasingly important for the production of renewable biofuels to address global energy concerns. Hemicellulose is the second most abundant lignocellulosic biopolymer consisting of mostly xylan and other polysaccharides. A variety of enzymes is involved in complete hydrolysis of xylan into its constituent sugars for subsequent biofuel fermentation. Two enzymes, endo-β-xylanase and β-xylosidase, are particularly important in hydrolyzing the xylan backbone into xylooligosaccharides and individual xylose units. In this study, we describe the cloning, expression, and characterization of xylanase and β-xylosidase isolated from Bacillus subtilis M015 in Escherichia coli. The genes were identified to encode a 213 amino acid protein for xylanase (glycoside hydrolase (GH) family 11) and a 533 amino acid protein for β-xylosidase (GH family 43). Recombinant enzymes were produced by periplasmic-leaky E. coli JE5505 and therefore secreted into the supernatant during growth. Temperature and pH optima were determined to be 50 °C and 5.5–6 for xylanase and 35 °C and 7.0–7.5 for β-xylosidase using beech wood xylan and p-nitrophenyl-β-D-xylopyranoside as the substrates, respectively. We have also investigated the synergy of two enzymes on xylan hydrolysis and observed 90 % increase in total sugar release (composed of xylose, xylobiose, xylotriose, and xylotetraose) for xylanase/β-xylosidase combination as opposed to xylanase alone.
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Affiliation(s)
- Alison L Banka
- Department of Chemical Engineering, University of Michigan, 3074 H.H.Dow Buil., 2300 Hayward St, Ann Arbor, MI, 48109, USA
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