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Li Q, Ma Q, Zhou Y, Jiang X, Parales RE, Zhao S, Zhuang Y, Ruan Z. Isolation, identification, and degradation mechanism by multi-omics of mesotrione-degrading Amycolatopsis nivea La24. JOURNAL OF HAZARDOUS MATERIALS 2024; 476:134951. [PMID: 38917628 DOI: 10.1016/j.jhazmat.2024.134951] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 03/20/2024] [Revised: 06/03/2024] [Accepted: 06/16/2024] [Indexed: 06/27/2024]
Abstract
Mesotrione is a herbicide used in agricultural production; however, its stability and long-term residues pose ecological risks to soil health and subsequent crops. In this research, the strain Amycolatopsis nivea La24 was identified as capable of completely degrading 50 mg∙L-1 mesotrione within 48 h. It exhibited a broad adaptability to various environment and could degrade three sulfonylurea herbicides (nicosulfuron, chlorimuron-methyl, and cinosulfuron). Non-target metabonomic and mass spectrometry demonstrated that La24 strain broke down the mesotrione parent molecule by targeting the β-diketone bond and nitro group, resulting in the production of five possible degradation products. The differentially expressed genes were significantly enriched in fatty acid degradation, amino acid metabolism, and other pathways, and the differentially metabolites in glutathione metabolism, arginine/proline metabolism, cysteine/methionine metabolism, and other pathways. Additionally, it was confirmed by heterologous expression that nitroreductase was directly involved in the mesotrione degradation, and NDMA-dependent methanol dehydrogenase would increase the resistance to mesotrione. Finally, the intracellular response of La24 during mesotrione degradation was proposed. This work provides insight for a comprehensive understanding of the mesotrione biodegradation mechanism, significantly expands the resources for pollutant degradation, and offers the potential for a more sustainable solution to address herbicide pollution in soil.
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Affiliation(s)
- Qingqing Li
- State Key Laboratory of Efficient Utilization of Arid and Semi-Arid Arable Land in Northern China, Institute of Agricultural Resources and Regional Planning, Chinese Academy of Agricultural Sciences, Beijing 100081, China; National Key Laboratory of Agricultural Microbiology and College of Life Science and Technology, Huazhong Agricultural University, Wuhan 430070, China
| | - Qingyun Ma
- State Key Laboratory of Efficient Utilization of Arid and Semi-Arid Arable Land in Northern China, Institute of Agricultural Resources and Regional Planning, Chinese Academy of Agricultural Sciences, Beijing 100081, China; National Key Laboratory of Agricultural Microbiology and College of Life Science and Technology, Huazhong Agricultural University, Wuhan 430070, China
| | - Yiqing Zhou
- State Key Laboratory of Efficient Utilization of Arid and Semi-Arid Arable Land in Northern China, Institute of Agricultural Resources and Regional Planning, Chinese Academy of Agricultural Sciences, Beijing 100081, China
| | - Xu Jiang
- State Key Laboratory of Efficient Utilization of Arid and Semi-Arid Arable Land in Northern China, Institute of Agricultural Resources and Regional Planning, Chinese Academy of Agricultural Sciences, Beijing 100081, China
| | - Rebecca E Parales
- Department of Microbiology and Molecular Genetics, College of Biological Sciences, University of California, Davis, CA 95616, USA
| | - Shumiao Zhao
- National Key Laboratory of Agricultural Microbiology and College of Life Science and Technology, Huazhong Agricultural University, Wuhan 430070, China
| | - Yan Zhuang
- State Key Laboratory of Efficient Utilization of Arid and Semi-Arid Arable Land in Northern China, Institute of Agricultural Resources and Regional Planning, Chinese Academy of Agricultural Sciences, Beijing 100081, China
| | - Zhiyong Ruan
- State Key Laboratory of Efficient Utilization of Arid and Semi-Arid Arable Land in Northern China, Institute of Agricultural Resources and Regional Planning, Chinese Academy of Agricultural Sciences, Beijing 100081, China; CAAS-CIAT Joint Laboratory in Advanced Technologies for Sustainable Agriculture, Institute of Agricultural Resources and Regional Planning, Chinese Academy of Agricultural Sciences, Beijing 100081, China.
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2
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Jing F, Chen K, Yandeau-Nelson MD, Nikolau BJ. Machine learning model of the catalytic efficiency and substrate specificity of acyl-ACP thioesterase variants generated from natural and in vitro directed evolution. Front Bioeng Biotechnol 2024; 12:1379121. [PMID: 38665811 PMCID: PMC11043601 DOI: 10.3389/fbioe.2024.1379121] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/30/2024] [Accepted: 03/28/2024] [Indexed: 04/28/2024] Open
Abstract
Modulating the catalytic activity of acyl-ACP thioesterase (TE) is an important biotechnological target for effectively increasing flux and diversifying products of the fatty acid biosynthesis pathway. In this study, a directed evolution approach was developed to improve the fatty acid titer and fatty acid diversity produced by E. coli strains expressing variant acyl-ACP TEs. A single round of in vitro directed evolution, coupled with a high-throughput colorimetric screen, identified 26 novel acyl-ACP TE variants that convey up to a 10-fold increase in fatty acid titer, and generate altered fatty acid profiles when expressed in a bacterial host strain. These in vitro-generated variant acyl-ACP TEs, in combination with 31 previously characterized natural variants isolated from diverse phylogenetic origins, were analyzed with a random forest classifier machine learning tool. The resulting quantitative model identified 22 amino acid residues, which define important structural features that determine the catalytic efficiency and substrate specificity of acyl-ACP TE.
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Affiliation(s)
- Fuyuan Jing
- Roy J. Carver Department of Biochemistry, Biophysics, and Molecular Biology, Iowa State University, Ames, IA, United States
- Center for Metabolic Biology, Iowa State University, Ames, IA, United States
- Engineering Research Center for Biorenewable Chemicals, Iowa State University, Ames, IA, United States
| | - Keting Chen
- Roy J. Carver Department of Biochemistry, Biophysics, and Molecular Biology, Iowa State University, Ames, IA, United States
- Department of Genetics, Development and Cell Biology, Iowa State University, Ames, IA, United States
| | - Marna D. Yandeau-Nelson
- Center for Metabolic Biology, Iowa State University, Ames, IA, United States
- Engineering Research Center for Biorenewable Chemicals, Iowa State University, Ames, IA, United States
- Department of Genetics, Development and Cell Biology, Iowa State University, Ames, IA, United States
| | - Basil J. Nikolau
- Roy J. Carver Department of Biochemistry, Biophysics, and Molecular Biology, Iowa State University, Ames, IA, United States
- Center for Metabolic Biology, Iowa State University, Ames, IA, United States
- Engineering Research Center for Biorenewable Chemicals, Iowa State University, Ames, IA, United States
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3
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Snoeck S, Guidi C, De Mey M. "Metabolic burden" explained: stress symptoms and its related responses induced by (over)expression of (heterologous) proteins in Escherichia coli. Microb Cell Fact 2024; 23:96. [PMID: 38555441 PMCID: PMC10981312 DOI: 10.1186/s12934-024-02370-9] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/01/2023] [Accepted: 03/18/2024] [Indexed: 04/02/2024] Open
Abstract
BACKGROUND Engineering bacterial strains to redirect the metabolism towards the production of a specific product has enabled the development of industrial biotechnology. However, rewiring the metabolism can have severe implications for a microorganism, rendering cells with stress symptoms such as a decreased growth rate, impaired protein synthesis, genetic instability and an aberrant cell size. On an industrial scale, this is reflected in processes that are not economically viable. MAIN TEXT In literature, most stress symptoms are attributed to "metabolic burden", however the actual triggers and stress mechanisms involved are poorly understood. Therefore, in this literature review, we aimed to get a better insight in how metabolic engineering affects Escherichia coli and link the observed stress symptoms to its cause. Understanding the possible implications that chosen engineering strategies have, will help to guide the reader towards optimising the envisioned process more efficiently. CONCLUSION This review addresses the gap in literature and discusses the triggers and effects of stress mechanisms that can be activated when (over)expressing (heterologous) proteins in Escherichia coli. It uncovers that the activation of the different stress mechanisms is complex and that many are interconnected. The reader is shown that care has to be taken when (over)expressing (heterologous) proteins as the cell's metabolism is tightly regulated.
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Affiliation(s)
- Sofie Snoeck
- Department of Biotechnology, Centre for Synthetic Biology, Coupure Links 653, Gent, 9000, Belgium
| | - Chiara Guidi
- Department of Biotechnology, Centre for Synthetic Biology, Coupure Links 653, Gent, 9000, Belgium
| | - Marjan De Mey
- Department of Biotechnology, Centre for Synthetic Biology, Coupure Links 653, Gent, 9000, Belgium.
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4
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Nam SH, Ye DY, Hwang HG, Jung GY. Convergent Synthesis of Two Heterogeneous Fluxes from Glucose and Acetate for High-Yield Citramalate Production. JOURNAL OF AGRICULTURAL AND FOOD CHEMISTRY 2024; 72:5797-5804. [PMID: 38465388 DOI: 10.1021/acs.jafc.3c09466] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 03/12/2024]
Abstract
Biological production of citramalate has garnered attention due to its wide application for food additives and pharmaceuticals, although improvement of yield is known to be challenging. When glucose is used as the sole carbon source, carbon loss through decarboxylation steps for providing acetyl-CoA from pyruvate is inevitable. To avoid this, we engineered a strain to co-utilize glucose and cost-effective acetate while preventing carbon loss for enhancing citramalate production. The production pathway diverged to independently supply the precursors required for the synthesis of citramalate from glucose and acetate, respectively. Moreover, the phosphotransferase system was inactivated and the acetate assimilation pathway and the substrate ratio were optimized to enable the simultaneous and efficient utilization of both carbon sources. This yielded results (5.0 g/L, 0.87 mol/mol) surpassing the yield and titer of the control strain utilizing glucose as the sole carbon source in flask cultures, demonstrating an economically efficient strain redesign strategy for synthesizing various products.
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Affiliation(s)
- Sung Hyun Nam
- School of Interdisciplinary Bioscience and Bioengineering, Pohang University of Science and Technology, 77 Cheongam-Ro, Nam-Gu, Pohang, Gyeongbuk 37673, Korea
| | - Dae-Yeol Ye
- Department of Chemical Engineering, Pohang University of Science and Technology, 77 Cheongam-Ro, Nam-Gu, Pohang, Gyeongbuk 37673, Korea
| | - Hyun Gyu Hwang
- Institute of Environmental and Energy Technology, Pohang University of Science and Technology, 77 Cheongam-Ro, Nam-Gu, Pohang, Gyeongbuk 37673, Korea
| | - Gyoo Yeol Jung
- School of Interdisciplinary Bioscience and Bioengineering, Pohang University of Science and Technology, 77 Cheongam-Ro, Nam-Gu, Pohang, Gyeongbuk 37673, Korea
- Department of Chemical Engineering, Pohang University of Science and Technology, 77 Cheongam-Ro, Nam-Gu, Pohang, Gyeongbuk 37673, Korea
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5
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Lu C, Wijffels RH, Martins Dos Santos VAP, Weusthuis RA. Pseudomonas putida as a platform for medium-chain length α,ω-diol production: Opportunities and challenges. Microb Biotechnol 2024; 17:e14423. [PMID: 38528784 DOI: 10.1111/1751-7915.14423] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/12/2023] [Revised: 01/18/2024] [Accepted: 01/26/2024] [Indexed: 03/27/2024] Open
Abstract
Medium-chain-length α,ω-diols (mcl-diols) play an important role in polymer production, traditionally depending on energy-intensive chemical processes. Microbial cell factories offer an alternative, but conventional strains like Escherichia coli and Saccharomyces cerevisiae face challenges in mcl-diol production due to the toxicity of intermediates such as alcohols and acids. Metabolic engineering and synthetic biology enable the engineering of non-model strains for such purposes with P. putida emerging as a promising microbial platform. This study reviews the advancement in diol production using P. putida and proposes a four-module approach for the sustainable production of diols. Despite progress, challenges persist, and this study discusses current obstacles and future opportunities for leveraging P. putida as a microbial cell factory for mcl-diol production. Furthermore, this study highlights the potential of using P. putida as an efficient chassis for diol synthesis.
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Affiliation(s)
- Chunzhe Lu
- Bioprocess Engineering, Wageningen University & Research, Wageningen, The Netherlands
- Groningen Biomolecular Sciences & Biotechnology Institute, University of Groningen, Groningen, The Netherlands
| | - Rene H Wijffels
- Bioprocess Engineering, Wageningen University & Research, Wageningen, The Netherlands
- Faculty of Biosciences and Aquaculture, Nord University, Bodø, Norway
| | - Vitor A P Martins Dos Santos
- Bioprocess Engineering, Wageningen University & Research, Wageningen, The Netherlands
- Lifeglimmer GmbH, Berlin, Germany
| | - Ruud A Weusthuis
- Bioprocess Engineering, Wageningen University & Research, Wageningen, The Netherlands
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6
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Kobalter S, Voit A, Bekerle-Bogner M, Rudalija H, Haas A, Wriessnegger T, Pichler H. Tuning Fatty Acid Profile and Yield in Pichia pastoris. Bioengineering (Basel) 2023; 10:1412. [PMID: 38136003 PMCID: PMC10741089 DOI: 10.3390/bioengineering10121412] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/02/2023] [Revised: 11/29/2023] [Accepted: 12/04/2023] [Indexed: 12/24/2023] Open
Abstract
Fatty acids have been supplied for diverse non-food, industrial applications from plant oils and animal fats for many decades. Due to the massively increasing world population demanding a nutritious diet and the thrive to provide feedstocks for industrial production lines in a sustainable way, i.e., independent from food supply chains, alternative fatty acid sources have massively gained in importance. Carbohydrate-rich side-streams of agricultural production, e.g., molasses, lignocellulosic waste, glycerol from biodiesel production, and even CO2, are considered and employed as carbon sources for the fermentative accumulation of fatty acids in selected microbial hosts. While certain fatty acid species are readily accumulated in native microbial metabolic routes, other fatty acid species are scarce, and host strains need to be metabolically engineered for their high-level production. We report the metabolic engineering of Pichia pastoris to produce palmitoleic acid from glucose and discuss the beneficial and detrimental engineering steps in detail. Fatty acid secretion was achieved through the deletion of fatty acyl-CoA synthetases and overexpression of the truncated E. coli thioesterase 'TesA. The best strains secreted >1 g/L free fatty acids into the culture medium. Additionally, the introduction of C16-specific ∆9-desaturases and fatty acid synthases, coupled with improved cultivation conditions, increased the palmitoleic acid content from 5.5% to 22%.
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Affiliation(s)
- Simon Kobalter
- Austrian Centre of Industrial Biotechnology (acib GmbH), Petersgasse 14, 8010 Graz, Austria; (S.K.)
| | - Alena Voit
- Austrian Centre of Industrial Biotechnology (acib GmbH), Petersgasse 14, 8010 Graz, Austria; (S.K.)
| | - Myria Bekerle-Bogner
- Austrian Centre of Industrial Biotechnology (acib GmbH), Petersgasse 14, 8010 Graz, Austria; (S.K.)
| | - Haris Rudalija
- Austrian Centre of Industrial Biotechnology (acib GmbH), Petersgasse 14, 8010 Graz, Austria; (S.K.)
| | - Anne Haas
- Austrian Centre of Industrial Biotechnology (acib GmbH), Petersgasse 14, 8010 Graz, Austria; (S.K.)
| | - Tamara Wriessnegger
- Austrian Centre of Industrial Biotechnology (acib GmbH), Petersgasse 14, 8010 Graz, Austria; (S.K.)
| | - Harald Pichler
- Austrian Centre of Industrial Biotechnology (acib GmbH), Petersgasse 14, 8010 Graz, Austria; (S.K.)
- Institute of Molecular Biotechnology, Graz University of Technology, NAWI Graz, BioTechMed Graz, Petersgasse 14, 8010 Graz, Austria
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7
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Strategies to Enhance the Biosynthesis of Monounsaturated Fatty Acids in Escherichia coli. BIOTECHNOL BIOPROC E 2023. [DOI: 10.1007/s12257-022-0295-2] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/25/2023]
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8
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Yamamoto Y, Yamada R, Matsumoto T, Ogino H. Construction of a machine-learning model to predict the optimal gene expression level for efficient production of D-lactic acid in yeast. World J Microbiol Biotechnol 2023; 39:69. [PMID: 36607503 DOI: 10.1007/s11274-022-03515-x] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/04/2022] [Accepted: 12/30/2022] [Indexed: 01/07/2023]
Abstract
The modification of gene expression is being researched in the production of useful chemicals by metabolic engineering of the yeast Saccharomyces cerevisiae. When the expression levels of many metabolic enzyme genes are modified simultaneously, the expression ratio of these genes becomes diverse; the relationship between the gene expression ratio and chemical productivity remains unclear. In other words, it is challenging to predict phenotypes from genotypes. However, the productivity of useful chemicals can be improved if this relationship is clarified. In this study, we aimed to construct a machine-learning model that can be used to clarify the relationship between gene expression levels and D-lactic acid productivity and predict the optimal gene expression level for efficient D-lactic acid production in yeast. A machine-learning model was constructed using data on D-lactate dehydrogenase and glycolytic genes expression (13 dimensions) and D-lactic acid productivity. The coefficient of determination of the completed machine-learning model was 0.6932 when using the training data and 0.6628 when using the test data. Using the constructed machine-learning model, we predicted the optimal gene expression level for high D-lactic acid production. We successfully constructed a machine-learning model to predict both D-lactic acid productivity and the suitable gene expression ratio for the production of D-lactic acid. The technique established in this study could be key for predicting phenotypes from genotypes, a problem faced by recent metabolic engineering strategies.
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Affiliation(s)
- Yoshiki Yamamoto
- Department of Chemical Engineering, Osaka Metropolitan University, 1-1 Gakuen-cho, Naka-ku, Sakai, Osaka, 599-8531, Japan
| | - Ryosuke Yamada
- Department of Chemical Engineering, Osaka Metropolitan University, 1-1 Gakuen-cho, Naka-ku, Sakai, Osaka, 599-8531, Japan.
| | - Takuya Matsumoto
- Department of Chemical Engineering, Osaka Metropolitan University, 1-1 Gakuen-cho, Naka-ku, Sakai, Osaka, 599-8531, Japan
| | - Hiroyasu Ogino
- Department of Chemical Engineering, Osaka Metropolitan University, 1-1 Gakuen-cho, Naka-ku, Sakai, Osaka, 599-8531, Japan
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9
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Kalinger RS, Rowland O. Determinants of substrate specificity in a catalytically diverse family of acyl-ACP thioesterases from plants. BMC PLANT BIOLOGY 2023; 23:1. [PMID: 36588156 PMCID: PMC9806908 DOI: 10.1186/s12870-022-04003-y] [Citation(s) in RCA: 15] [Impact Index Per Article: 15.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 09/07/2022] [Accepted: 12/13/2022] [Indexed: 05/05/2023]
Abstract
BACKGROUND ACYL-LIPID THIOESTERASES (ALTs) are a subclass of plastid-localized, fatty acyl-acyl carrier protein (ACP) thioesterase enzymes from plants. They belong to the single hot dog-fold protein family. ALT enzymes generate medium-chain (C6-C14) and C16 fatty acids, methylketone precursors (β-keto fatty acids), and 3-hydroxy fatty acids when expressed heterologously in E. coli. The diverse substrate chain-length and oxidation state preferences of ALTs set them apart from other plant acyl-ACP thioesterases, and ALTs show promise as metabolic engineering tools to produce high-value medium-chain fatty acids and methylketones in bacterial or plant systems. Here, we used a targeted motif-swapping approach to explore connections between ALT protein sequence and substrate specificity. Guided by comparative motif searches and computational modelling, we exchanged regions of amino acid sequence between ALT-type thioesterases from Arabidopsis thaliana, Medicago truncatula, and Zea mays to create chimeric ALT proteins. RESULTS Comparing the activity profiles of chimeric ALTs in E. coli to their wild-type counterparts led to the identification of interacting regions within the thioesterase domain that shape substrate specificity and enzyme activity. Notably, the presence of a 31-CQH[G/C]RH-36 motif on the central α-helix was shown to shift chain-length specificity towards 12-14 carbon chains, and to be a core determinant of substrate specificity in ALT-type thioesterases with preference for 12-14 carbon 3-hydroxyacyl- and β-ketoacyl-ACP substrates. For an ALT containing this motif to be functional, an additional 108-KXXA-111 motif and compatible sequence spanning aa77-93 of the surrounding β-sheet must also be present, demonstrating that interactions between residues in these regions of the catalytic domain are critical to thioesterase activity. The behaviour of chimeric enzymes in E. coli also indicated that aa77-93 play a significant role in dictating whether an ALT will prefer ≤10-carbon or ≥ 12-carbon acyl chain-lengths, and aa91-96 influence selectivity for substrates of fully or partially reduced oxidation states. Additionally, aa64-67 on the hot dog-fold β-sheet were shown to be important for enabling an ALT to act on 3-hydroxy fatty acyl-ACP substrates. CONCLUSIONS By revealing connections between thioesterase sequence and substrate specificity, this study is an advancement towards engineering recombinant ALTs with product profiles suited for specific applications.
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Affiliation(s)
- Rebecca S Kalinger
- Department of Biology and Institute of Biochemistry, Carleton University, 1125 Colonel By Drive, Ottawa, Ontario, K1S 5B6, Canada
| | - Owen Rowland
- Department of Biology and Institute of Biochemistry, Carleton University, 1125 Colonel By Drive, Ottawa, Ontario, K1S 5B6, Canada.
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10
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Valencia LE, Incha MR, Schmidt M, Pearson AN, Thompson MG, Roberts JB, Mehling M, Yin K, Sun N, Oka A, Shih PM, Blank LM, Gladden J, Keasling JD. Engineering Pseudomonas putida KT2440 for chain length tailored free fatty acid and oleochemical production. Commun Biol 2022; 5:1363. [PMID: 36509863 PMCID: PMC9744835 DOI: 10.1038/s42003-022-04336-2] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/14/2022] [Accepted: 12/02/2022] [Indexed: 12/15/2022] Open
Abstract
Despite advances in understanding the metabolism of Pseudomonas putida KT2440, a promising bacterial host for producing valuable chemicals from plant-derived feedstocks, a strain capable of producing free fatty acid-derived chemicals has not been developed. Guided by functional genomics, we engineered P. putida to produce medium- and long-chain free fatty acids (FFAs) to titers of up to 670 mg/L. Additionally, by taking advantage of the varying substrate preferences of paralogous native fatty acyl-CoA ligases, we employed a strategy to control FFA chain length that resulted in a P. putida strain specialized in producing medium-chain FFAs. Finally, we demonstrate the production of oleochemicals in these strains by synthesizing medium-chain fatty acid methyl esters, compounds useful as biodiesel blending agents, in various media including sorghum hydrolysate at titers greater than 300 mg/L. This work paves the road to produce high-value oleochemicals and biofuels from cheap feedstocks, such as plant biomass, using this host.
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Affiliation(s)
- Luis E. Valencia
- grid.451372.60000 0004 0407 8980Joint BioEnergy Institute, Emeryville, CA 94608 USA ,grid.184769.50000 0001 2231 4551Biological Systems and Engineering Division, Lawrence Berkeley National Laboratory, Berkeley, CA 94720 USA ,grid.47840.3f0000 0001 2181 7878Department of Bioengineering, University of California, Berkeley, CA 94720 USA
| | - Matthew R. Incha
- grid.451372.60000 0004 0407 8980Joint BioEnergy Institute, Emeryville, CA 94608 USA ,grid.184769.50000 0001 2231 4551Biological Systems and Engineering Division, Lawrence Berkeley National Laboratory, Berkeley, CA 94720 USA ,grid.47840.3f0000 0001 2181 7878Department of Plant and Microbial Biology, University of California, Berkeley, CA 94720 USA
| | - Matthias Schmidt
- grid.451372.60000 0004 0407 8980Joint BioEnergy Institute, Emeryville, CA 94608 USA ,grid.184769.50000 0001 2231 4551Biological Systems and Engineering Division, Lawrence Berkeley National Laboratory, Berkeley, CA 94720 USA ,grid.1957.a0000 0001 0728 696XInstitute of Applied Microbiology (iAMB), Aachen Biology and Biotechnology (ABBt), RWTH Aachen University, Aachen, Germany
| | - Allison N. Pearson
- grid.451372.60000 0004 0407 8980Joint BioEnergy Institute, Emeryville, CA 94608 USA ,grid.184769.50000 0001 2231 4551Biological Systems and Engineering Division, Lawrence Berkeley National Laboratory, Berkeley, CA 94720 USA ,grid.47840.3f0000 0001 2181 7878Department of Plant and Microbial Biology, University of California, Berkeley, CA 94720 USA
| | - Mitchell G. Thompson
- grid.451372.60000 0004 0407 8980Joint BioEnergy Institute, Emeryville, CA 94608 USA ,grid.184769.50000 0001 2231 4551Environmental Genomics and Systems Biology Division, Lawrence Berkeley National Laboratory, Berkeley, CA USA
| | - Jacob B. Roberts
- grid.451372.60000 0004 0407 8980Joint BioEnergy Institute, Emeryville, CA 94608 USA ,grid.184769.50000 0001 2231 4551Biological Systems and Engineering Division, Lawrence Berkeley National Laboratory, Berkeley, CA 94720 USA ,grid.47840.3f0000 0001 2181 7878Department of Bioengineering, University of California, Berkeley, CA 94720 USA
| | - Marina Mehling
- grid.451372.60000 0004 0407 8980Joint BioEnergy Institute, Emeryville, CA 94608 USA ,grid.184769.50000 0001 2231 4551Biological Systems and Engineering Division, Lawrence Berkeley National Laboratory, Berkeley, CA 94720 USA
| | - Kevin Yin
- grid.451372.60000 0004 0407 8980Joint BioEnergy Institute, Emeryville, CA 94608 USA ,grid.184769.50000 0001 2231 4551Biological Systems and Engineering Division, Lawrence Berkeley National Laboratory, Berkeley, CA 94720 USA ,grid.47840.3f0000 0001 2181 7878Department of Plant and Microbial Biology, University of California, Berkeley, CA 94720 USA
| | - Ning Sun
- grid.184769.50000 0001 2231 4551Biological Systems and Engineering Division, Lawrence Berkeley National Laboratory, Berkeley, CA 94720 USA ,Advanced Biofuels and Bioproducts Process Demonstration Unit, Emeryville, CA 94608 USA
| | - Asun Oka
- grid.184769.50000 0001 2231 4551Biological Systems and Engineering Division, Lawrence Berkeley National Laboratory, Berkeley, CA 94720 USA ,Advanced Biofuels and Bioproducts Process Demonstration Unit, Emeryville, CA 94608 USA
| | - Patrick M. Shih
- grid.451372.60000 0004 0407 8980Joint BioEnergy Institute, Emeryville, CA 94608 USA ,grid.184769.50000 0001 2231 4551Biological Systems and Engineering Division, Lawrence Berkeley National Laboratory, Berkeley, CA 94720 USA ,grid.47840.3f0000 0001 2181 7878Department of Plant and Microbial Biology, University of California, Berkeley, CA 94720 USA ,grid.184769.50000 0001 2231 4551Environmental Genomics and Systems Biology Division, Lawrence Berkeley National Laboratory, Berkeley, CA USA
| | - Lars M. Blank
- grid.1957.a0000 0001 0728 696XInstitute of Applied Microbiology (iAMB), Aachen Biology and Biotechnology (ABBt), RWTH Aachen University, Aachen, Germany
| | - John Gladden
- grid.451372.60000 0004 0407 8980Joint BioEnergy Institute, Emeryville, CA 94608 USA ,grid.474523.30000000403888279Biomanufacturing and Biomaterials Department, Sandia National Laboratories, Livermore, CA 94550 USA
| | - Jay D. Keasling
- grid.451372.60000 0004 0407 8980Joint BioEnergy Institute, Emeryville, CA 94608 USA ,grid.184769.50000 0001 2231 4551Biological Systems and Engineering Division, Lawrence Berkeley National Laboratory, Berkeley, CA 94720 USA ,grid.47840.3f0000 0001 2181 7878Department of Bioengineering, University of California, Berkeley, CA 94720 USA ,grid.47840.3f0000 0001 2181 7878Department of Chemical & Biomolecular Engineering, University of California, Berkeley, CA 94720 USA ,grid.5170.30000 0001 2181 8870Center for Biosustainability, Technical University of Denmark, Lyngby, Denmark ,Center for Synthetic Biochemistry, Institute of Synthetic Biology, Shenzhen Institutes of Advanced Technologies, Shenzhen, China
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11
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Park WS, Shin KS, Jung HW, Lee Y, Sathesh-Prabu C, Lee SK. Combinatorial Metabolic Engineering Strategies for the Enhanced Production of Free Fatty Acids in Escherichia coli. JOURNAL OF AGRICULTURAL AND FOOD CHEMISTRY 2022; 70:13913-13921. [PMID: 36200488 DOI: 10.1021/acs.jafc.2c04621] [Citation(s) in RCA: 4] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/16/2023]
Abstract
In this study, we evaluated the effects of several metabolic engineering strategies in a systematic and combinatorial manner to enhance the free fatty acid (FFA) production in Escherichia coli. The strategies included (i) overexpression of mutant thioesterase I ('TesAR64C) to efficiently release the FFAs from fatty acyl-ACP; (ii) coexpression of global regulatory protein FadR; (iii) heterologous expression of methylmalonyl-CoA carboxyltransferase and phosphoenolpyruvate carboxylase to synthesize fatty acid precursor molecule malonyl-CoA; and (iv) disruption of genes associated with membrane proteins (GusC, MdlA, and EnvR) to improve the cellular state and export the FFAs outside the cell. The synergistic effects of these genetic modifications in strain SBF50 yielded 7.2 ± 0.11 g/L FFAs at the shake flask level. In fed-batch cultivation under nitrogen-limiting conditions, strain SBF50 produced 33.6 ± 0.02 g/L FFAs with a productivity of 0.7 g/L/h from glucose, which is the maximum titer reported in E. coli to date. Combinatorial metabolic engineering approaches can prove to be highly useful for the large-scale production of FA-derived chemicals and fuels.
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Affiliation(s)
- Woo Sang Park
- School of Energy & Chemical Engineering, Ulsan National Institute of Science and Technology (UNIST), Ulsan 44919, Republic of Korea
| | - Kwang Soo Shin
- School of Energy & Chemical Engineering, Ulsan National Institute of Science and Technology (UNIST), Ulsan 44919, Republic of Korea
| | - Hyun Wook Jung
- School of Energy & Chemical Engineering, Ulsan National Institute of Science and Technology (UNIST), Ulsan 44919, Republic of Korea
| | - Yongjoo Lee
- School of Energy & Chemical Engineering, Ulsan National Institute of Science and Technology (UNIST), Ulsan 44919, Republic of Korea
| | - Chandran Sathesh-Prabu
- School of Energy & Chemical Engineering, Ulsan National Institute of Science and Technology (UNIST), Ulsan 44919, Republic of Korea
| | - Sung Kuk Lee
- School of Energy & Chemical Engineering, Ulsan National Institute of Science and Technology (UNIST), Ulsan 44919, Republic of Korea
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12
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Microbial pathways for advanced biofuel production. Biochem Soc Trans 2022; 50:987-1001. [PMID: 35411379 PMCID: PMC9162456 DOI: 10.1042/bst20210764] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/10/2021] [Revised: 03/14/2022] [Accepted: 03/25/2022] [Indexed: 01/16/2023]
Abstract
Decarbonisation of the transport sector is essential to mitigate anthropogenic climate change. Microbial metabolisms are already integral to the production of renewable, sustainable fuels and, building on that foundation, are being re-engineered to generate the advanced biofuels that will maintain mobility of people and goods during the energy transition. This review surveys the range of natural and engineered microbial systems for advanced biofuels production and summarises some of the techno-economic challenges associated with their implementation at industrial scales.
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13
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Metabolic engineering strategies to produce medium-chain oleochemicals via acyl-ACP:CoA transacylase activity. Nat Commun 2022; 13:1619. [PMID: 35338129 PMCID: PMC8956717 DOI: 10.1038/s41467-022-29218-3] [Citation(s) in RCA: 8] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/24/2021] [Accepted: 03/04/2022] [Indexed: 11/12/2022] Open
Abstract
Microbial lipid metabolism is an attractive route for producing oleochemicals. The predominant strategy centers on heterologous thioesterases to synthesize desired chain-length fatty acids. To convert acids to oleochemicals (e.g., fatty alcohols, ketones), the narrowed fatty acid pool needs to be reactivated as coenzyme A thioesters at cost of one ATP per reactivation - an expense that could be saved if the acyl-chain was directly transferred from ACP- to CoA-thioester. Here, we demonstrate such an alternative acyl-transferase strategy by heterologous expression of PhaG, an enzyme first identified in Pseudomonads, that transfers 3-hydroxy acyl-chains between acyl-carrier protein and coenzyme A thioester forms for creating polyhydroxyalkanoate monomers. We use it to create a pool of acyl-CoA’s that can be redirected to oleochemical products. Through bioprospecting, mutagenesis, and metabolic engineering, we develop three strains of Escherichia coli capable of producing over 1 g/L of medium-chain free fatty acids, fatty alcohols, and methyl ketones. Microbial production of oleochemicals involves strategies of expressing thioesterase to narrow the substrate pool for the termination enzyme at the expense of one ATP. Here, the authors developed an alternative energy-efficient strategy to use of an acyl-ACP transacylase to produce medium chain oleochemicals in E. coli.
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14
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Caswell BT, de Carvalho CC, Nguyen H, Roy M, Nguyen T, Cantu DC. Thioesterase enzyme families: Functions, structures, and mechanisms. Protein Sci 2022; 31:652-676. [PMID: 34921469 PMCID: PMC8862431 DOI: 10.1002/pro.4263] [Citation(s) in RCA: 14] [Impact Index Per Article: 7.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/25/2021] [Revised: 12/11/2021] [Accepted: 12/14/2021] [Indexed: 12/12/2022]
Abstract
Thioesterases are enzymes that hydrolyze thioester bonds in numerous biochemical pathways, for example in fatty acid synthesis. This work reports known functions, structures, and mechanisms of updated thioesterase enzyme families, which are classified into 35 families based on sequence similarity. Each thioesterase family is based on at least one experimentally characterized enzyme, and most families have enzymes that have been crystallized and their tertiary structure resolved. Classifying thioesterases into families allows to predict tertiary structures and infer catalytic residues and mechanisms of all sequences in a family, which is particularly useful because the majority of known protein sequence have no experimental characterization. Phylogenetic analysis of experimentally characterized thioesterases that have structures with the two main structural folds reveal convergent and divergent evolution. Based on tertiary structure superimposition, catalytic residues are predicted.
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Affiliation(s)
- Benjamin T. Caswell
- Department of Chemical and Materials EngineeringUniversity of Nevada, RenoRenoNevadaUSA
| | - Caio C. de Carvalho
- Department of Chemical and Materials EngineeringUniversity of Nevada, RenoRenoNevadaUSA
| | - Hung Nguyen
- Department of Computer Science and EngineeringUniversity of Nevada, RenoRenoNevadaUSA
| | - Monikrishna Roy
- Department of Computer Science and EngineeringUniversity of Nevada, RenoRenoNevadaUSA
| | - Tin Nguyen
- Department of Computer Science and EngineeringUniversity of Nevada, RenoRenoNevadaUSA
| | - David C. Cantu
- Department of Chemical and Materials EngineeringUniversity of Nevada, RenoRenoNevadaUSA
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15
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Partipilo G, Graham AJ, Belardi B, Keitz BK. Extracellular Electron Transfer Enables Cellular Control of Cu(I)-Catalyzed Alkyne-Azide Cycloaddition. ACS CENTRAL SCIENCE 2022; 8:246-257. [PMID: 35233456 PMCID: PMC8875427 DOI: 10.1021/acscentsci.1c01208] [Citation(s) in RCA: 2] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 10/01/2021] [Indexed: 05/03/2023]
Abstract
Extracellular electron transfer (EET) is an anaerobic respiration process that couples carbon oxidation to the reduction of metal species. In the presence of a suitable metal catalyst, EET allows for cellular metabolism to control a variety of synthetic transformations. Here, we report the use of EET from the electroactive bacterium Shewanella oneidensis for metabolic and genetic control over Cu(I)-catalyzed alkyne-azide cycloaddition (CuAAC). CuAAC conversion under anaerobic and aerobic conditions was dependent on live, actively respiring S. oneidensis cells. The reaction progress and kinetics were manipulated by tailoring the central carbon metabolism. Similarly, EET-CuAAC activity was dependent on specific EET pathways that could be regulated via inducible expression of EET-relevant proteins: MtrC, MtrA, and CymA. EET-driven CuAAC exhibited modularity and robustness in the ligand and substrate scope. Furthermore, the living nature of this system could be exploited to perform multiple reaction cycles without regeneration, something inaccessible to traditional chemical reductants. Finally, S. oneidensis enabled bioorthogonal CuAAC membrane labeling on live mammalian cells without affecting cell viability, suggesting that S. oneidensis can act as a dynamically tunable biocatalyst in complex environments. In summary, our results demonstrate how EET can expand the reaction scope available to living systems by enabling cellular control of CuAAC.
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Affiliation(s)
- Gina Partipilo
- McKetta
Department of Chemical Engineering, University
of Texas at Austin, Austin, Texas 78712, United States
- Center
for Dynamics and Control of Materials, University
of Texas at Austin, Austin, Texas 78712, United States
| | - Austin J. Graham
- McKetta
Department of Chemical Engineering, University
of Texas at Austin, Austin, Texas 78712, United States
- Center
for Dynamics and Control of Materials, University
of Texas at Austin, Austin, Texas 78712, United States
| | - Brian Belardi
- McKetta
Department of Chemical Engineering, University
of Texas at Austin, Austin, Texas 78712, United States
| | - Benjamin K. Keitz
- McKetta
Department of Chemical Engineering, University
of Texas at Austin, Austin, Texas 78712, United States
- Center
for Dynamics and Control of Materials, University
of Texas at Austin, Austin, Texas 78712, United States
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16
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Enespa, Chandra P, Singh DP. Sources, purification, immobilization and industrial applications of microbial lipases: An overview. Crit Rev Food Sci Nutr 2022; 63:6653-6686. [PMID: 35179093 DOI: 10.1080/10408398.2022.2038076] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/07/2023]
Abstract
Microbial lipase is looking for better attention with the fast growth of enzyme proficiency and other benefits like easy, cost-effective, and reliable manufacturing. Immobilized enzymes can be used repetitively and are incapable to catalyze the reactions in the system continuously. Hydrophobic supports are utilized to immobilize enzymes when the ionic strength is low. This approach allows for the immobilization, purification, stability, and hyperactivation of lipases in a single step. The diffusion of the substrate is more advantageous on hydrophobic supports than on hydrophilic supports in the carrier. These approaches are critical to the immobilization performance of the enzyme. For enzyme immobilization, synthesis provides a higher pH value as well as greater heat stability. Using a mixture of immobilization methods, the binding force between enzymes and the support rises, reducing enzyme leakage. Lipase adsorption produces interfacial activation when it is immobilized on hydrophobic support. As a result, in the immobilization process, this procedure is primarily used for a variety of industrial applications. Microbial sources, immobilization techniques, and industrial applications in the fields of food, flavor, detergent, paper and pulp, pharmaceuticals, biodiesel, derivatives of esters and amino groups, agrochemicals, biosensor applications, cosmetics, perfumery, and bioremediation are all discussed in this review.
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Affiliation(s)
- Enespa
- School for Agriculture, Sri Mahesh Prasad Post Graduate College, University of Lucknow, Lucknow, Uttar Pradesh, India
| | - Prem Chandra
- Food Microbiology & Toxicology Laboratory, Department of Microbiology, School for Environmental Sciences, Babasaheb Bhimrao Ambedkar University (A Central) University, Lucknow, Uttar Pradesh, India
| | - Devendra Pratap Singh
- Department of Environmental Science, School for Environmental Sciences, Babasaheb Bhimrao Ambedkar University (A Central) University, Lucknow, Uttar Pradesh, India
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17
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18
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Banerjee D, Jindra MA, Linot AJ, Pfleger BF, Maranas CD. EnZymClass: Substrate specificity prediction tool of plant acyl-ACP thioesterases based on ensemble learning. CURRENT RESEARCH IN BIOTECHNOLOGY 2022. [DOI: 10.1016/j.crbiot.2021.12.002] [Citation(s) in RCA: 2] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/09/2023] Open
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19
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Accelerating strain phenotyping with desorption electrospray ionization-imaging mass spectrometry and untargeted analysis of intact microbial colonies. Proc Natl Acad Sci U S A 2021; 118:2109633118. [PMID: 34857637 DOI: 10.1073/pnas.2109633118] [Citation(s) in RCA: 6] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Accepted: 10/26/2021] [Indexed: 11/18/2022] Open
Abstract
Reading and writing DNA were once the rate-limiting step in synthetic biology workflows. This has been replaced by the search for the optimal target sequences to produce systems with desired properties. Directed evolution and screening mutant libraries are proven technologies for isolating strains with enhanced performance whenever specialized assays are available for rapidly detecting a phenotype of interest. Armed with technologies such as CRISPR-Cas9, these experiments are capable of generating libraries of up to 1010 genetic variants. At a rate of 102 samples per day, standard analytical methods for assessing metabolic phenotypes represent a major bottleneck to modern synthetic biology workflows. To address this issue, we have developed a desorption electrospray ionization-imaging mass spectrometry screening assay that directly samples microorganisms. This technology increases the throughput of metabolic measurements by reducing sample preparation and analyzing organisms in a multiplexed fashion. To further accelerate synthetic biology workflows, we utilized untargeted acquisitions and unsupervised analytics to assess multiple targets for future engineering strategies within a single acquisition. We demonstrate the utility of the developed method using Escherichia coli strains engineered to overproduce free fatty acids. We determined discrete metabolic phenotypes associated with each strain, which include the primary fatty acid product, secondary products, and additional metabolites outside the engineered product pathway. Furthermore, we measured changes in amino acid levels and membrane lipid composition, which affect cell viability. In sum, we present an analytical method to accelerate synthetic biology workflows through rapid, untargeted, and multiplexed metabolomic analyses.
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20
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Sawant N, Singh H, Appukuttan D. Overview of the Cellular Stress Responses Involved in Fatty Acid Overproduction in E. coli. Mol Biotechnol 2021; 64:373-387. [PMID: 34796451 DOI: 10.1007/s12033-021-00426-4] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/07/2021] [Accepted: 11/10/2021] [Indexed: 12/29/2022]
Abstract
Research on microbial fatty acid metabolism started in the late 1960s, and till date, various developments have aided in elucidating the fatty acid metabolism in great depth. Over the years, synthesis of microbial fatty acid has drawn industrial attention due to its diverse applications. However, fatty acid overproduction imparts various stresses on its metabolic pathways causing a bottleneck to further increase the fatty acid yields. Numerous strategies to increase fatty acid titres in Escherichia coli by pathway modulation have already been published, but the stress generated during fatty acid overproduction is relatively less studied. Stresses like pH, osmolarity and oxidative stress, not only lower fatty acid titres, but also alter the cell membrane composition, protein expression and membrane fluidity. This review discusses an overview of fatty acid synthesis pathway and presents a panoramic view of various stresses caused due to fatty acid overproduction in E. coli. It also addresses how certain stresses like high temperature and nitrogen limitation can boost fatty acid production. This review paper also highlights the interconnections that exist between these stresses.
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Affiliation(s)
- Neha Sawant
- Department of Biological Sciences, Sunandan Divatia School of Science, NMIMS Deemed to be University, Vile Parle (West), Mumbai, 400056, India
| | - Harinder Singh
- Department of Biological Sciences, Sunandan Divatia School of Science, NMIMS Deemed to be University, Vile Parle (West), Mumbai, 400056, India.
| | - Deepti Appukuttan
- Biosystems Engineering Lab, Department of Chemical Engineering, IIT Bombay, Powai, Mumbai, 400076, India.
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21
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Keasling J, Garcia Martin H, Lee TS, Mukhopadhyay A, Singer SW, Sundstrom E. Microbial production of advanced biofuels. Nat Rev Microbiol 2021; 19:701-715. [PMID: 34172951 DOI: 10.1038/s41579-021-00577-w] [Citation(s) in RCA: 79] [Impact Index Per Article: 26.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Accepted: 05/13/2021] [Indexed: 02/06/2023]
Abstract
Concerns over climate change have necessitated a rethinking of our transportation infrastructure. One possible alternative to carbon-polluting fossil fuels is biofuels produced by engineered microorganisms that use a renewable carbon source. Two biofuels, ethanol and biodiesel, have made inroads in displacing petroleum-based fuels, but their uptake has been limited by the amounts that can be used in conventional engines and by their cost. Advanced biofuels that mimic petroleum-based fuels are not limited by the amounts that can be used in existing transportation infrastructure but have had limited uptake due to costs. In this Review, we discuss engineering metabolic pathways to produce advanced biofuels, challenges with substrate and product toxicity with regard to host microorganisms and methods to engineer tolerance, and the use of functional genomics and machine learning approaches to produce advanced biofuels and prospects for reducing their costs.
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Affiliation(s)
- Jay Keasling
- Joint BioEnergy Institute, Emeryville, CA, USA. .,Department of Chemical & Biomolecular Engineering, University of California, Berkeley, Berkeley, CA, USA. .,Department of Bioengineering, University of California, Berkeley, Berkeley, CA, USA. .,Biological Systems and Engineering Division, Lawrence Berkeley National Laboratory, Berkeley, CA, USA. .,Center for Biosustainability, Danish Technical University, Lyngby, Denmark. .,Center for Synthetic Biochemistry, Institute for Synthetic Biology, Shenzhen Institute of Advanced Technology, Shenzhen, China.
| | - Hector Garcia Martin
- Joint BioEnergy Institute, Emeryville, CA, USA.,Biological Systems and Engineering Division, Lawrence Berkeley National Laboratory, Berkeley, CA, USA.,DOE Agile BioFoundry, Emeryville, CA, USA.,BCAM,Basque Center for Applied Mathematics, Bilbao, Spain.,Environmental Genomics and Systems Biology Division, Lawrence Berkeley National Laboratory, Berkeley, CA, USA
| | - Taek Soon Lee
- Joint BioEnergy Institute, Emeryville, CA, USA.,Biological Systems and Engineering Division, Lawrence Berkeley National Laboratory, Berkeley, CA, USA
| | - Aindrila Mukhopadhyay
- Joint BioEnergy Institute, Emeryville, CA, USA.,Biological Systems and Engineering Division, Lawrence Berkeley National Laboratory, Berkeley, CA, USA.,Environmental Genomics and Systems Biology Division, Lawrence Berkeley National Laboratory, Berkeley, CA, USA
| | - Steven W Singer
- Joint BioEnergy Institute, Emeryville, CA, USA.,Biological Systems and Engineering Division, Lawrence Berkeley National Laboratory, Berkeley, CA, USA
| | - Eric Sundstrom
- Biological Systems and Engineering Division, Lawrence Berkeley National Laboratory, Berkeley, CA, USA.,Advanced Biofuels and Bioproducts Process Development Unit, Emeryville, CA, USA
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22
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Eungrasamee K, Incharoensakdi A, Lindblad P, Jantaro S. Overexpression of lipA or glpD_RuBisCO in the Synechocystis sp. PCC 6803 Mutant Lacking the Aas Gene Enhances Free Fatty-Acid Secretion and Intracellular Lipid Accumulation. Int J Mol Sci 2021; 22:ijms222111468. [PMID: 34768898 PMCID: PMC8583886 DOI: 10.3390/ijms222111468] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/24/2021] [Revised: 10/16/2021] [Accepted: 10/21/2021] [Indexed: 11/16/2022] Open
Abstract
Although engineered cyanobacteria for the production of lipids and fatty acids (FAs) are intelligently used as sustainable biofuel resources, intracellularly overproduced FAs disturb cellular homeostasis and eventually generate lethal toxicity. In order to improve their production by enhancing FFAs secretion into a medium, we constructed three engineered Synechocystis 6803 strains including KA (a mutant lacking the aas gene), KAOL (KA overexpressing lipA, encoding lipase A in membrane lipid hydrolysis), and KAOGR (KA overexpressing quadruple glpD/rbcLXS, related to the CBB cycle). Certain contents of intracellular lipids and secreted FFAs of all engineered strains were higher than those of the wild type. Remarkably, the KAOL strain attained the highest level of secreted FFAs by about 21.9%w/DCW at day 5 of normal BG11 cultivation, with a higher growth rate and shorter doubling time. TEM images provided crucial evidence on the morphological changes of the KAOL strain, which accumulated abundant droplets on regions of thylakoid membranes throughout the cell when compared with wild type. On the other hand, BG11-N condition significantly induced contents of both intracellular lipids and secreted FFAs of the KAOL strain up to 37.2 and 24.5%w/DCW, respectively, within 5 days. Then, for the first time, we shone a spotlight onto the overexpression of lipA in the aas mutant of Synechocystis as another potential strategy to achieve higher FFAs secretion with sustainable growth.
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Affiliation(s)
- Kamonchanock Eungrasamee
- Laboratory of Cyanobacterial Biotechnology, Department of Biochemistry, Faculty of Science, Chulalongkorn University, Bangkok 10330, Thailand; (K.E.); (A.I.)
| | - Aran Incharoensakdi
- Laboratory of Cyanobacterial Biotechnology, Department of Biochemistry, Faculty of Science, Chulalongkorn University, Bangkok 10330, Thailand; (K.E.); (A.I.)
| | - Peter Lindblad
- Microbial Chemistry, Department of Chemistry–Ångström, Uppsala University, Box 523, SE-75120 Uppsala, Sweden;
| | - Saowarath Jantaro
- Laboratory of Cyanobacterial Biotechnology, Department of Biochemistry, Faculty of Science, Chulalongkorn University, Bangkok 10330, Thailand; (K.E.); (A.I.)
- Correspondence: ; Tel.: +66-(0)2-218-5431; Fax: +66-(0)2-218-5418
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23
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Chou A, Lee SH, Zhu F, Clomburg JM, Gonzalez R. An orthogonal metabolic framework for one-carbon utilization. Nat Metab 2021; 3:1385-1399. [PMID: 34675440 DOI: 10.1038/s42255-021-00453-0] [Citation(s) in RCA: 26] [Impact Index Per Article: 8.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 10/11/2020] [Accepted: 08/10/2021] [Indexed: 11/09/2022]
Abstract
Metabolic engineering often entails concurrent engineering of substrate utilization, central metabolism and product synthesis pathways, inevitably creating interdependency with native metabolism. Here we report an alternative approach using synthetic pathways for C1 bioconversion that generate multicarbon products directly from C1 units and hence are orthogonal to the host metabolic network. The engineered pathways are based on formyl-CoA elongation (FORCE) reactions catalysed by the enzyme 2-hydroxyacyl-CoA lyase. We use thermodynamic and stoichiometric analyses to evaluate FORCE pathway variants, including aldose elongation, α-reduction and aldehyde elongation. Promising variants were prototyped in vitro and in vivo using the non-methylotrophic bacterium Escherichia coli. We demonstrate the conversion of formate, formaldehyde and methanol into various products including glycolate, ethylene glycol, ethanol and glycerate. FORCE pathways also have the potential to be integrated with the host metabolism for synthetic methylotrophy by the production of native growth substrates as demonstrated in a two-strain co-culture system.
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Affiliation(s)
- Alexander Chou
- Department of Chemical, Biological and Materials Engineering, University of South Florida, Tampa, FL, USA
| | - Seung Hwan Lee
- Department of Chemical, Biological and Materials Engineering, University of South Florida, Tampa, FL, USA
| | - Fayin Zhu
- Department of Chemical, Biological and Materials Engineering, University of South Florida, Tampa, FL, USA
| | - James M Clomburg
- Department of Chemical, Biological and Materials Engineering, University of South Florida, Tampa, FL, USA
| | - Ramon Gonzalez
- Department of Chemical, Biological and Materials Engineering, University of South Florida, Tampa, FL, USA.
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24
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Flores AD, Holland SC, Mhatre A, Sarnaik AP, Godar A, Onyeabor M, Varman AM, Wang X, Nielsen DR. A coculture-coproduction system designed for enhanced carbon conservation through inter-strain CO 2 recycling. Metab Eng 2021; 67:387-395. [PMID: 34365009 DOI: 10.1016/j.ymben.2021.08.001] [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: 04/27/2021] [Revised: 07/08/2021] [Accepted: 08/04/2021] [Indexed: 11/30/2022]
Abstract
Carbon loss in the form of CO2 is an intrinsic and persistent challenge faced during conventional and advanced biofuel production from biomass feedstocks. Current mechanisms for increasing carbon conservation typically require the provision of reduced co-substrates as additional reducing equivalents. This need can be circumvented, however, by exploiting the natural heterogeneity of lignocellulosic sugars mixtures and strategically using specific fractions to drive complementary CO2 emitting vs. CO2 fixing pathways. As a demonstration of concept, a coculture-coproduction system was developed by pairing two catabolically orthogonal Escherichia coli strains; one converting glucose to ethanol (G2E) and the other xylose to succinate (X2S). 13C-labeling studies reveled that G2E + X2S cocultures were capable of recycling 24% of all evolved CO2 and achieved a carbon conservation efficiency of 77%; significantly higher than the 64% achieved when all sugars are instead converted to just ethanol. In addition to CO2 exchange, the latent exchange of pyruvate between strains was discovered, along with significant carbon rearrangement within X2S.
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Affiliation(s)
- Andrew D Flores
- Chemical Engineering, School for Engineering of Matter, Transport, and Energy, Arizona State University, AZ 85287, ECG 301, 501 E. Tyler Mall, Arizona, 85287, United States
| | - Steven C Holland
- School of Life Sciences, Arizona State University, 427 E. Tyler Mall, Tempe, AZ, 85287, United States
| | - Apurv Mhatre
- Chemical Engineering, School for Engineering of Matter, Transport, and Energy, Arizona State University, AZ 85287, ECG 301, 501 E. Tyler Mall, Arizona, 85287, United States
| | - Aditya P Sarnaik
- Chemical Engineering, School for Engineering of Matter, Transport, and Energy, Arizona State University, AZ 85287, ECG 301, 501 E. Tyler Mall, Arizona, 85287, United States
| | - Amanda Godar
- School of Life Sciences, Arizona State University, 427 E. Tyler Mall, Tempe, AZ, 85287, United States
| | - Moses Onyeabor
- School of Life Sciences, Arizona State University, 427 E. Tyler Mall, Tempe, AZ, 85287, United States
| | - Arul M Varman
- Chemical Engineering, School for Engineering of Matter, Transport, and Energy, Arizona State University, AZ 85287, ECG 301, 501 E. Tyler Mall, Arizona, 85287, United States
| | - Xuan Wang
- School of Life Sciences, Arizona State University, 427 E. Tyler Mall, Tempe, AZ, 85287, United States.
| | - David R Nielsen
- Chemical Engineering, School for Engineering of Matter, Transport, and Energy, Arizona State University, AZ 85287, ECG 301, 501 E. Tyler Mall, Arizona, 85287, United States.
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25
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Functional Analysis of an Acyltransferase-Like Domain from Polyunsaturated Fatty Acid Synthase in Thraustochytrium. Microorganisms 2021; 9:microorganisms9030626. [PMID: 33803061 PMCID: PMC8003026 DOI: 10.3390/microorganisms9030626] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/12/2021] [Revised: 03/15/2021] [Accepted: 03/15/2021] [Indexed: 12/19/2022] Open
Abstract
Biosynthesis of very long chain polyunsaturated fatty acids (VLCPUFA) such as docosahexaenoic acid (DHA, 22:6-4,7,10,13,16,19) and docosapentaenoic acid (DPA, 22:5-4,7,10,13,16) in protist Thraustochytrium is catalyzed by a polyunsaturated fatty acids (PUFA) synthase comprising three large subunits, each with multiple catalytic domains. This study used complementation test, in vitro assays, and functional expression to characterize an acyltransferase (AT)-like domain in Subunit-B of a PUFA synthase from Thraustochytrium. Complementation test in Escherichia coli showed that the AT-like domain could not restore the growth phenotype of a temperature-sensitive mutant (∆fabDts) defective in malonyl-CoA:ACP transacylase activity. In vitro assays showed that the AT-like domain possessed thioesterase activity towards a few acyl-CoAs tested where docosahexaenoyl-CoA (DHA-CoA) was the preferred substrate. Expression of this domain in an E. coli mutant (∆fadD) defective in acyl-CoA synthetase activity resulted in the increased accumulation of free fatty acids. Site-directed mutagenesis showed that the substitution of two putative active site residues, serine at 96 (S96) and histidine at 220 (H220), in the AT-like domain significantly reduced its activity towards DHA-CoA and accumulation of free fatty acids in the ∆fadD mutant. These results indicate that the AT-like domain of the PUFA synthase does not function as a malonyl-CoA:ACP transacylase, rather it functions as a thioesterase. It might catalyze the last step of the VLCPUFA biosynthesis by releasing freshly synthesized VLCPUFAs attached to ACP domains of the PUFA synthase in Thraustochytrium.
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Awad G, Garnier A. Maximization of saturated fatty acids through the production of P450BM3 monooxygenase in the engineered Escherichia coli. FOOD AND BIOPRODUCTS PROCESSING 2021. [DOI: 10.1016/j.fbp.2021.01.001] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 11/15/2022]
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A Futile Metabolic Cycle of Fatty Acyl-CoA Hydrolysis and Resynthesis in Corynebacterium glutamicum and Its Disruption Leading to Fatty Acid Production. Appl Environ Microbiol 2021; 87:AEM.02469-20. [PMID: 33310719 PMCID: PMC7851686 DOI: 10.1128/aem.02469-20] [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] [Indexed: 11/26/2022] Open
Abstract
Fatty acyl-CoA thioesterase (Tes) and acyl-CoA synthetase (FadD) catalyze opposing reactions between acyl-CoAs and free fatty acids. Within the genome of Corynebacterium glutamicum, several candidate genes for each enzyme are present, although their functions remain unknown. Modified expressions of the candidate genes in the fatty acid producer WTΔfasR led to identification of one tes gene (tesA) and two fadD genes (fadD5 and fadD15), which functioned positively and negatively in fatty acid production, respectively. Genetic analysis showed that fadD5 and fadD15 are responsible for utilization of exogenous fatty acids and that tesA plays a role in supplying fatty acids for synthesis of the outer layer components mycolic acids. Enzyme assays and expression analysis revealed that tesA, fadD5, and fadD15 were co-expressed to create a cyclic route between acyl-CoAs and fatty acids. When fadD5 or fadD15 was disrupted in wild-type C. glutamicum, both disruptants excreted fatty acids during growth. Double disruptions of them resulted in a synergistic increase in production. Additional disruption of tesA revealed a canceling effect on production. These results indicate that the FadDs normally shunt the surplus of TesA-generated fatty acids back to acyl-CoAs for lipid biosynthesis and that interception of this shunt provokes cells to overproduce fatty acids. When this strategy was applied to a fatty acid high-producer, the resulting fadDs-disrupted and tesA-amplified strain exhibited a 72% yield increase relative to its parent and produced fatty acids, which consisted mainly of oleic acid, palmitic acid, and stearic acid, on the gram scale per liter from 1% glucose.IMPORTANCE The industrial amino acid producer Corynebacterium glutamicum has currently evolved into a potential workhorse for fatty acid production. In this organism, we obtained evidence showing the presence of a unique mechanism of lipid homeostasis, namely, a formation of a futile cycle of acyl-CoA hydrolysis and resynthesis mediated by acyl-CoA thioesterase (Tes) and acyl-CoA synthetase (FadD), respectively. The biological role of the coupling of Tes and FadD would be to supply free fatty acids for synthesis of the outer layer components mycolic acids and to recycle their surplusage to acyl-CoAs for membrane lipid synthesis. We further demonstrated that engineering of the cycle in a fatty acid high-producer led to dramatically improved production, which provides a useful engineering strategy for fatty acid production in this industrially important microorganism.
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Leandro M, Andrade L, Vespoli L, Moreira J, Pimentel V, Soares F, Passamani L, Silveira V, de Souza Filho G. Comparative proteomics reveals essential mechanisms for osmotolerance in Gluconacetobacter diazotrophicus. Res Microbiol 2020; 172:103785. [PMID: 33035671 DOI: 10.1016/j.resmic.2020.09.005] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/12/2020] [Revised: 09/24/2020] [Accepted: 09/25/2020] [Indexed: 12/17/2022]
Abstract
Plant growth-promoting bacteria are a promising alternative to improve agricultural sustainability. Gluconacetobacter diazotrophicus is an osmotolerant bacterium able to colonize several plant species, including sugarcane, coffee, and rice. Despite its biotechnological potential, the mechanisms controlling such osmotolerance remain unclear. The present study investigated the key mechanisms of resistance to osmotic stress in G. diazotrophicus. The molecular pathways regulated by the stress were investigated by comparative proteomics, and proteins essential for resistance were identified by knock-out mutagenesis. Proteomics analysis led to identify regulatory pathways for osmotic adjustment, de novo saturated fatty acids biosynthesis, and uptake of nutrients. The mutagenesis analysis showed that the lack of AccC protein, an essential component of de novo fatty acid biosynthesis, severely affected G. diazotrophicus resistance to osmotic stress. Additionally, knock-out mutants for nutrients uptake (Δtbdr and ΔoprB) and compatible solutes synthesis (ΔmtlK and ΔotsA) became more sensitive to osmotic stress. Together, our results identified specific genes and mechanisms regulated by osmotic stress in an osmotolerant bacterium, shedding light on the essential role of cell envelope and extracytoplasmic proteins for osmotolerance.
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Affiliation(s)
- Mariana Leandro
- Laboratório de Biotecnologia (Setor de Biologia Integrativa), Universidade Estadual do Norte Fluminense Darcy Ribeiro (UENF), Campos dos Goytacazes, Rio de Janeiro, Brazil.
| | - Leandro Andrade
- Laboratório de Biotecnologia (Setor de Biologia Integrativa), Universidade Estadual do Norte Fluminense Darcy Ribeiro (UENF), Campos dos Goytacazes, Rio de Janeiro, Brazil.
| | - Luciano Vespoli
- Laboratório de Biotecnologia (Setor de Biologia Integrativa), Universidade Estadual do Norte Fluminense Darcy Ribeiro (UENF), Campos dos Goytacazes, Rio de Janeiro, Brazil.
| | - Julia Moreira
- Laboratório de Biotecnologia (Setor de Biologia Integrativa), Universidade Estadual do Norte Fluminense Darcy Ribeiro (UENF), Campos dos Goytacazes, Rio de Janeiro, Brazil.
| | - Vivian Pimentel
- Laboratório de Biotecnologia (Setor de Biologia Integrativa), Universidade Estadual do Norte Fluminense Darcy Ribeiro (UENF), Campos dos Goytacazes, Rio de Janeiro, Brazil.
| | - Fabiano Soares
- Laboratório de Biotecnologia (Setor de Biologia Integrativa), Universidade Estadual do Norte Fluminense Darcy Ribeiro (UENF), Campos dos Goytacazes, Rio de Janeiro, Brazil.
| | - Lucas Passamani
- Laboratório de Biotecnologia (Setor de Biologia Integrativa), Universidade Estadual do Norte Fluminense Darcy Ribeiro (UENF), Campos dos Goytacazes, Rio de Janeiro, Brazil.
| | - Vanildo Silveira
- Laboratório de Biotecnologia (Setor de Biologia Integrativa), Universidade Estadual do Norte Fluminense Darcy Ribeiro (UENF), Campos dos Goytacazes, Rio de Janeiro, Brazil.
| | - Gonçalo de Souza Filho
- Laboratório de Biotecnologia (Setor de Biologia Integrativa), Universidade Estadual do Norte Fluminense Darcy Ribeiro (UENF), Campos dos Goytacazes, Rio de Janeiro, Brazil.
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Ge J, Yang X, Yu H, Ye L. High-yield whole cell biosynthesis of Nylon 12 monomer with self-sufficient supply of multiple cofactors. Metab Eng 2020; 62:172-185. [PMID: 32927060 DOI: 10.1016/j.ymben.2020.09.006] [Citation(s) in RCA: 13] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/20/2020] [Revised: 07/09/2020] [Accepted: 09/09/2020] [Indexed: 12/19/2022]
Abstract
Biosynthesis of Nylon 12 monomer using dodecanoic acid (DDA) or its esters as the renewable feedstock typically involves ω-hydroxylation, oxidation and ω-amination. The dependence of hydroxylation and oxidation-catalyzing enzymes on redox cofactors, and the requirement of L-alanine as the co-substrate and pyridoxal 5'-phosphate (PLP) as the coenzyme for transamination, raise the issue of redox imbalance and cofactor shortage, challenging the development of efficient biocatalysts. Simultaneous regeneration of the redox equivalents, PLP and L-alanine required in the artificial pathway was enabled by its interfacing with the native metabolism of the host using glucose dehydrogenase (GDH), L-alanine dehydrogenase (AlaDH) and an exogenous ribose 5-phosphate (R5P)-dependent PLP synthesis pathway as bridges. Further engineering of the host by blocking β-oxidation and enhancing substrate uptake improved the ω-aminododecanoic acid (ω-AmDDA) yield to 96.5%. This study offers a strategy to resolve the cofactor imbalance issue commonly encountered in whole-cell biocatalysis and meanwhile lays a solid foundation for Nylon 12 bioproduction.
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Affiliation(s)
- Jiawei Ge
- Key Laboratory of Biomass Chemical Engineering (Education Ministry), College of Chemical and Biological Engineering, Zhejiang University, Hangzhou, 310027, China; Institute of Bioengineering, College of Chemical and Biological Engineering, Zhejiang University, Hangzhou, 310027, China
| | - Xiaohong Yang
- Institute of Bioengineering, College of Chemical and Biological Engineering, Zhejiang University, Hangzhou, 310027, China
| | - Hongwei Yu
- Key Laboratory of Biomass Chemical Engineering (Education Ministry), College of Chemical and Biological Engineering, Zhejiang University, Hangzhou, 310027, China; Institute of Bioengineering, College of Chemical and Biological Engineering, Zhejiang University, Hangzhou, 310027, China
| | - Lidan Ye
- Key Laboratory of Biomass Chemical Engineering (Education Ministry), College of Chemical and Biological Engineering, Zhejiang University, Hangzhou, 310027, China; Institute of Bioengineering, College of Chemical and Biological Engineering, Zhejiang University, Hangzhou, 310027, China.
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A kinetic rationale for functional redundancy in fatty acid biosynthesis. Proc Natl Acad Sci U S A 2020; 117:23557-23564. [PMID: 32883882 DOI: 10.1073/pnas.2013924117] [Citation(s) in RCA: 9] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/18/2022] Open
Abstract
Cells build fatty acids with biocatalytic assembly lines in which a subset of enzymes often exhibit overlapping activities (e.g., two enzymes catalyze one or more identical reactions). Although the discrete enzymes that make up fatty acid pathways are well characterized, the importance of catalytic overlap between them is poorly understood. We developed a detailed kinetic model of the fatty acid synthase (FAS) of Escherichia coli and paired that model with a fully reconstituted in vitro system to examine the capabilities afforded by functional redundancy in fatty acid synthesis. The model captures-and helps explain-the effects of experimental perturbations to FAS systems and provides a powerful tool for guiding experimental investigations of fatty acid assembly. Compositional analyses carried out in silico and in vitro indicate that FASs with multiple partially redundant enzymes enable tighter (i.e., more independent and/or broader range) control of distinct biochemical objectives-the total production, unsaturated fraction, and average length of fatty acids-than FASs with only a single multifunctional version of each enzyme (i.e., one enzyme with the catalytic capabilities of two partially redundant enzymes). Maximal production of unsaturated fatty acids, for example, requires a second dehydratase that is not essential for their synthesis. This work provides a kinetic, control-theoretic rationale for the inclusion of partially redundant enzymes in fatty acid pathways and supplies a valuable framework for carrying out detailed studies of FAS kinetics.
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Venkateswar Reddy M, Kumar G, Mohanakrishna G, Shobana S, Al-Raoush RI. Review on the production of medium and small chain fatty acids through waste valorization and CO 2 fixation. BIORESOURCE TECHNOLOGY 2020; 309:123400. [PMID: 32371319 DOI: 10.1016/j.biortech.2020.123400] [Citation(s) in RCA: 23] [Impact Index Per Article: 5.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 02/13/2020] [Revised: 04/15/2020] [Accepted: 04/16/2020] [Indexed: 06/11/2023]
Abstract
The developing approaches in the recovery of resources from biowastes for the production of renewable value-added products and fuels, using microbial cultures as bio-catalyst have now became promising aspect. In the path of anaerobic digestion, the microorganisms are assisting transformation of a complex organic feedstock/waste to biomass and biogas. This potentiality consequently leads to the production of intermediate precursors of renewable value-added products. Particularly, a set of anaerobic pathways in the fermentation process, yields small-chain fatty acids (SCFA), and medium-chain fatty acids (MCFA) via chain elongation pathways from waste valorization and CO2 fixation. This review focuses on the production of SCFA and MCFA from CO2, synthetic substrates and waste materials. Moreover, the review introduces the metabolic engineering of Escherichia coli and Saccharomyces cerevisiae for SCFAs/MCFAs production. Furtherly, it concludes that future critical research might target progress of this promising approach as a valorization of complex organic wastes.
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Affiliation(s)
- M Venkateswar Reddy
- Institut für Molekulare Mikrobiologie und Biotechnologie, Westfälische Wilhelms Universität, Corrensstr. 3, 48149 Münster, Germany
| | - Gopalakrishnan Kumar
- School of Civil and Environmental Engineering, Yonsei University, Seoul 03722, Republic of Korea
| | - Gunda Mohanakrishna
- Department of Civil and Architectural Engineering, College of Engineering, Qatar University, P O Box 2713, Doha, Qatar.
| | - Sutha Shobana
- Department of Chemistry & Research Centre, Mohamed Sathak Engineering College, Kilakarai, 623 806 Ramanathapuram, Tamil Nadu, India
| | - Riyadh I Al-Raoush
- Department of Civil and Architectural Engineering, College of Engineering, Qatar University, P O Box 2713, Doha, Qatar
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Hernández Lozada NJ, Simmons TR, Xu K, Jindra MA, Pfleger BF. Production of 1-octanol in Escherichia coli by a high flux thioesterase route. Metab Eng 2020; 61:352-359. [PMID: 32707169 DOI: 10.1016/j.ymben.2020.07.004] [Citation(s) in RCA: 13] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/17/2020] [Revised: 06/10/2020] [Accepted: 07/07/2020] [Indexed: 10/23/2022]
Abstract
1-octanol is a valuable molecule in the chemical industry, where it is used as a plasticizer, as a precursor in the production of linear low-density polyethylene (LLDPE), and as a growth inhibitor of tobacco plant suckers. Due to the low availability of eight-carbon acyl chains in natural lipid feedstocks and the selectivity challenges in petrochemical routes to medium-chain fatty alcohols,1-octanol sells for the highest price among the fatty alcohol products. As an alternative, metabolic engineers have pursued sustainable 1-octanol production via engineered microbes. Here, we report demonstration of gram per liter titers in the model bacterium Escherichia coli via the development of a pathway composed of a thioesterase, an acyl-CoA synthetase, and an acyl-CoA reductase. In addition, the impact of deleting fermentative pathways was explored E. coli K12 MG1655 strain for production of octanoic acid, a key octanol precursor. In order to overcome metabolic flux barriers, bioprospecting experiments were performed to identify acyl-CoA synthetases with high activity towards octanoic acid and acyl-CoA reductases with high activity to produce 1-octanol from octanoyl-CoA. Titration of expression of key pathway enzymes was performed and a strain with the full pathway integrated on the chromosome was created. The final strain produced 1-octanol at 1.3 g/L titer and a >90% C8 specificity from glycerol. In addition to the metabolic engineering efforts, this work addressed some of the technical challenges that arise when quantifying 1-octanol produced from cultures grown under fully aerobic conditions where evaporation and stripping are prevalent.
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Affiliation(s)
- Néstor J Hernández Lozada
- Department of Chemical and Biological Engineering, University of Wisconsin-Madison, 1415 Engineering Drive, Madison, WI, 53706, USA
| | - Trevor R Simmons
- Department of Chemical and Biological Engineering, University of Wisconsin-Madison, 1415 Engineering Drive, Madison, WI, 53706, USA
| | - Ke Xu
- Department of Chemical and Biological Engineering, University of Wisconsin-Madison, 1415 Engineering Drive, Madison, WI, 53706, USA
| | - Michael A Jindra
- Department of Chemical and Biological Engineering, University of Wisconsin-Madison, 1415 Engineering Drive, Madison, WI, 53706, USA
| | - Brian F Pfleger
- Department of Chemical and Biological Engineering, University of Wisconsin-Madison, 1415 Engineering Drive, Madison, WI, 53706, USA.
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Deng X, Chen L, Hei M, Liu T, Feng Y, Yang GY. Structure-guided reshaping of the acyl binding pocket of 'TesA thioesterase enhances octanoic acid production in E. coli. Metab Eng 2020; 61:24-32. [PMID: 32339761 DOI: 10.1016/j.ymben.2020.04.010] [Citation(s) in RCA: 11] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/11/2020] [Revised: 03/23/2020] [Accepted: 04/16/2020] [Indexed: 12/21/2022]
Abstract
Medium-chain fatty acids (C6-C10) have attracted much attention recently for their unique properties compared to their long-chain counterparts, including low melting points and relatively higher carbon conversion yield. Thioesterase enzymes, which can catalyze the hydrolysis of acyl-ACP (acyl carrier protein) to release free fatty acids (FAs), regulate both overall FA yields and acyl chain length distributions in bacterial and yeast fermentation cultures. These enzymes typically prefer longer chain substrates. Herein, seeking to increase bacterial production of MCFAs, we conducted structure-guided mutational screening of multiple residues in the substrate-binding pocket of the E. coli thioesterase enzyme 'TesA. Confirming our hypothesis that enhancing substrate selectivity for medium-chain acyl substrates would promote overall MCFA production, we found that replacement of residues lining the bottom of the pocket with more hydrophobic residues strongly promoted the C8 substrate selectivity of 'TesA. Specifically, two rounds of saturation mutagenesis led to the identification of the 'TesARD-2 variant that exhibited a 133-fold increase in selectivity for the C8-ACP substrate as compared to C16-ACP substrate. Moreover, the recombinant expression of this variant in an E. coli strain with a blocked β-oxidation pathway led to a 1030% increase in the in vivo octanoic acid (C8) production titer. When this strain was fermented in a 5-L fed-batch bioreactor, it produced 2.7 g/L of free C8 (45%, molar fraction) and 7.9 g/L of total free FAs, which is the highest-to-date free C8 titer to date reported using the E. coli type II fatty acid synthetic pathway. Thus, reshaping the substrate binding pocket of a bacterial thioesterase enzyme by manipulating the hydrophobicity of multiple residues altered the substrate selectivity and therefore fatty acid product distributions in cells. Our study demonstrates the relevance of this strategy for increasing titers of industrially attractive MCFAs as fermentation products.
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Affiliation(s)
- Xi Deng
- State Key Laboratory of Microbial Metabolism, Joint International Research Laboratory of Metabolic & Developmental Sciences, School of Life Sciences and Biotechnology, Shanghai Jiao Tong University, Shanghai, 200240, China
| | - Liuqing Chen
- State Key Laboratory of Microbial Metabolism, Joint International Research Laboratory of Metabolic & Developmental Sciences, School of Life Sciences and Biotechnology, Shanghai Jiao Tong University, Shanghai, 200240, China
| | - Mohan Hei
- State Key Laboratory of Microbial Metabolism, Joint International Research Laboratory of Metabolic & Developmental Sciences, School of Life Sciences and Biotechnology, Shanghai Jiao Tong University, Shanghai, 200240, China
| | - Tiangang Liu
- Key Laboratory of Combinatorial Biosynthesis and Drug Discovery, Ministry of Education, and School of Pharmaceutical Sciences, Wuhan University, Wuhan, 430072, China
| | - Yan Feng
- State Key Laboratory of Microbial Metabolism, Joint International Research Laboratory of Metabolic & Developmental Sciences, School of Life Sciences and Biotechnology, Shanghai Jiao Tong University, Shanghai, 200240, China.
| | - Guang-Yu Yang
- State Key Laboratory of Microbial Metabolism, Joint International Research Laboratory of Metabolic & Developmental Sciences, School of Life Sciences and Biotechnology, Shanghai Jiao Tong University, Shanghai, 200240, China.
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Onyeabor M, Martinez R, Kurgan G, Wang X. Engineering transport systems for microbial production. ADVANCES IN APPLIED MICROBIOLOGY 2020; 111:33-87. [PMID: 32446412 DOI: 10.1016/bs.aambs.2020.01.002] [Citation(s) in RCA: 8] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 01/22/2023]
Abstract
The rapid development in the field of metabolic engineering has enabled complex modifications of metabolic pathways to generate a diverse product portfolio. Manipulating substrate uptake and product export is an important research area in metabolic engineering. Optimization of transport systems has the potential to enhance microbial production of renewable fuels and chemicals. This chapter comprehensively reviews the transport systems critical for microbial production as well as current genetic engineering strategies to improve transport functions and thus production metrics. In addition, this chapter highlights recent advancements in engineering microbial efflux systems to enhance cellular tolerance to industrially relevant chemical stress. Lastly, future directions to address current technological gaps are discussed.
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Affiliation(s)
- Moses Onyeabor
- School of Life Sciences, Arizona State University, Tempe, AZ, United States
| | - Rodrigo Martinez
- School of Life Sciences, Arizona State University, Tempe, AZ, United States
| | - Gavin Kurgan
- School of Life Sciences, Arizona State University, Tempe, AZ, United States
| | - Xuan Wang
- School of Life Sciences, Arizona State University, Tempe, AZ, United States.
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Enhanced Production of Fatty Acid Ethyl Ester with Engineered fabHDG Operon in Escherichia coli. Microorganisms 2019; 7:microorganisms7110552. [PMID: 31717929 PMCID: PMC6920873 DOI: 10.3390/microorganisms7110552] [Citation(s) in RCA: 6] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/05/2019] [Revised: 10/23/2019] [Accepted: 11/05/2019] [Indexed: 12/16/2022] Open
Abstract
Biodiesel, or fatty acid ethyl ester (FAEE), is an environmentally safe, next-generation biofuel. Conventionally, FAEE is produced by the conversion of oil/fats, obtained from plants, animals, and microorganisms, by transesterification. Recently, metabolic engineering of bacteria for ready-to-use biodiesel was developed. In Escherichia coli, it is produced by fatty acyl-carrier proteins and ethanol, with the help of thioesterase (TesB) and wax synthase (WS) enzymes. One of the foremost barriers in microbial FAEE production is the feedback inhibition of the fatty acid (FA) operon (fabHDG). Here, we studied the effect of biodiesel biosynthesis in E. coli with an engineered fabHDG operon. With a basic FAEE producing BD1 strain harboring tes and ws genes, biodiesel of 32 mg/L were produced. Optimal FAEE biosynthesis was achieved in the BD2 strain that carries an overexpressed operon (fabH, fabD, and fabG genes) and achieved up to 1291 mg/L of biodiesel, a 40-fold rise compared to the BD1 strain. The composition of FAEE obtained from the BD2 strain was 65% (C10:C2, decanoic acid ethyl ester) and 35% (C12:C2, dodecanoic acid ethyl ester). Our findings indicate that overexpression of the native FA operon, along with FAEE biosynthesis enzymes, improved biodiesel biosynthesis in E. coli.
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He Q, Bennett GN, San KY, Wu H. Biosynthesis of Medium-Chain ω-Hydroxy Fatty Acids by AlkBGT of Pseudomonas putida GPo1 With Native FadL in Engineered Escherichia coli. Front Bioeng Biotechnol 2019; 7:273. [PMID: 31681749 PMCID: PMC6812396 DOI: 10.3389/fbioe.2019.00273] [Citation(s) in RCA: 8] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/10/2019] [Accepted: 10/01/2019] [Indexed: 12/19/2022] Open
Abstract
Hydroxy fatty acids (HFAs) are valuable compounds that are widely used in medical, cosmetic and food fields. Production of ω-HFAs via bioconversion by engineered Escherichia coli has received a lot of attention because this process is environmentally friendly. In this study, a whole-cell bio-catalysis strategy was established to synthesize medium-chain ω-HFAs based on the AlkBGT hydroxylation system from Pseudomonas putida GPo1. The effects of blocking the β-oxidation of fatty acids (FAs) and enhancing the transportation of FAs on ω-HFAs bio-production were also investigated. When fadE and fadD were deleted, the consumption of decanoic acid decreased, and the yield of ω-hydroxydecanoic acid was enhanced remarkably. Additionally, the co-expression of the FA transporter protein, FadL, played an important role in increasing the conversion rate of ω-hydroxydecanoic acid. As a result, the concentration and yield of ω-hydroxydecanoic acid in NH03(pBGT-fadL) increased to 309 mg/L and 0.86 mol/mol, respectively. This whole-cell bio-catalysis system was further applied to the biosynthesis of ω-hydroxyoctanoic acid and ω-hydroxydodecanoic acid using octanoic acid and dodecanoic acid as substrates, respectively. The concentrations of ω-hydroxyoctanoic acid and ω-hydroxydodecanoic acid reached 275.48 and 249.03 mg/L, with yields of 0.63 and 0.56 mol/mol, respectively. This study demonstrated that the overexpression of AlkBGT coupled with native FadL is an efficient strategy to synthesize medium-chain ω-HFAs from medium-chain FAs in fadE and fadD mutant E. coli strains.
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Affiliation(s)
- Qiaofei He
- State Key Laboratory of Bioreactor Engineering, East China University of Science and Technology, Shanghai, China
| | - George N. Bennett
- Department of Chemical and Biomolecular Engineering, Rice University, Houston, TX, United States
| | - Ka-Yiu San
- Department of Bioengineering, Rice University, Houston, TX, United States
- Department of Chemical and Biomolecular Engineering, Rice University, Houston, TX, United States
| | - Hui Wu
- State Key Laboratory of Bioreactor Engineering, East China University of Science and Technology, Shanghai, China
- Shanghai Collaborative Innovation Center for Biomanufacturing Technology, Shanghai, China
- Key Laboratory of Bio-based Material Engineering of China National Light Industry Council, Shanghai, China
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Yang K, Qiao Y, Li F, Xu Y, Yan Y, Madzak C, Yan J. Subcellular engineering of lipase dependent pathways directed towards lipid related organelles for highly effectively compartmentalized biosynthesis of triacylglycerol derived products in Yarrowia lipolytica. Metab Eng 2019; 55:231-238. [DOI: 10.1016/j.ymben.2019.08.001] [Citation(s) in RCA: 30] [Impact Index Per Article: 6.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/09/2019] [Revised: 07/11/2019] [Accepted: 08/02/2019] [Indexed: 11/25/2022]
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Chacón MG, Kendrick EG, Leak DJ. Engineering Escherichia coli for the production of butyl octanoate from endogenous octanoyl-CoA. PeerJ 2019; 7:e6971. [PMID: 31304053 PMCID: PMC6610577 DOI: 10.7717/peerj.6971] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/10/2018] [Accepted: 04/18/2019] [Indexed: 11/20/2022] Open
Abstract
Medium chain esters produced from fruits and flowering plants have a number of commercial applications including use as flavour and fragrance ingredients, biofuels, and in pharmaceutical formulations. These esters are typically made via the activity of an alcohol acyl transferase (AAT) enzyme which catalyses the condensation of an alcohol and an acyl-CoA. Developing a microbial platform for medium chain ester production using AAT activity presents several obstacles, including the low product specificity of these enzymes for the desired ester and/or low endogenous substrate availability. In this study, we engineered Escherichia coli for the production of butyl octanoate from endogenously produced octanoyl-CoA. This was achieved through rational protein engineering of an AAT enzyme from Actinidia chinensis for improved octanoyl-CoA substrate specificity and metabolic engineering of E. coli fatty acid metabolism for increased endogenous octanoyl-CoA availability. This resulted in accumulation of 3.3 + 0.1 mg/L butyl octanoate as the sole product from E. coli after 48 h. This study represents a preliminary examination of the feasibility of developing E. coli platforms for the synthesis single medium chain esters from endogenous fatty acids.
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Affiliation(s)
- Micaela G Chacón
- Department of Biology and Biochemistry, University of Bath, Bath, England
| | | | - David J Leak
- Department of Biology and Biochemistry, University of Bath, Bath, England
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Yan Q, Pfleger BF. Revisiting metabolic engineering strategies for microbial synthesis of oleochemicals. Metab Eng 2019; 58:35-46. [PMID: 31022535 DOI: 10.1016/j.ymben.2019.04.009] [Citation(s) in RCA: 61] [Impact Index Per Article: 12.2] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/14/2019] [Revised: 04/20/2019] [Accepted: 04/21/2019] [Indexed: 02/06/2023]
Abstract
Microbial production of oleochemicals from renewable feedstocks remains an attractive route to produce high-energy density, liquid transportation fuels and high-value chemical products. Metabolic engineering strategies have been applied to demonstrate production of a wide range of oleochemicals, including free fatty acids, fatty alcohols, esters, olefins, alkanes, ketones, and polyesters in both bacteria and yeast. The majority of these demonstrations synthesized products containing long-chain fatty acids. These successes motivated additional effort to produce analogous molecules comprised of medium-chain fatty acids, molecules that are less common in natural oils and therefore of higher commercial value. Substantial progress has been made towards producing a subset of these chemicals, but significant work remains for most. The other primary challenge to producing oleochemicals in microbes is improving the performance, in terms of yield, rate, and titer, of biocatalysts such that economic large-scale processes are feasible. Common metabolic engineering strategies include blocking pathways that compete with synthesis of oleochemical building blocks and/or consume products, pulling flux through pathways by removing regulatory signals, pushing flux into biosynthesis by overexpressing rate-limiting enzymes, and engineering cells to tolerate the presence of oleochemical products. In this review, we describe the basic fundamentals of oleochemical synthesis and summarize advances since 2013 towards improving performance of heterotrophic microbial cell factories.
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Affiliation(s)
- Qiang Yan
- Department of Chemical and Biological Engineering, University of Wisconsin-Madison, Madison, WI 53706, United States; DOE Center for Advanced Bioenergy and Bioproducts Innovation, University of Wisconsin-Madison, Madison, WI 53706, United States
| | - Brian F Pfleger
- Department of Chemical and Biological Engineering, University of Wisconsin-Madison, Madison, WI 53706, United States; DOE Center for Advanced Bioenergy and Bioproducts Innovation, University of Wisconsin-Madison, Madison, WI 53706, United States; Microbiology Doctoral Training Program, University of Wisconsin-Madison, Madison, WI 53706, United States.
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Heterologous production of free dihomo-γ-linolenic acid by Aspergillus oryzae and its extracellular release via surfactant supplementation. J Biosci Bioeng 2019; 127:451-457. [DOI: 10.1016/j.jbiosc.2018.09.013] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/11/2018] [Revised: 08/29/2018] [Accepted: 09/20/2018] [Indexed: 01/21/2023]
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Microbial Production of Fatty Acid via Metabolic Engineering and Synthetic Biology. BIOTECHNOL BIOPROC E 2019. [DOI: 10.1007/s12257-018-0374-6] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/27/2022]
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42
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Zhao Y, Wu BH, Liu ZN, Qiao J, Zhao GR. Combinatorial Optimization of Resveratrol Production in Engineered E. coli. JOURNAL OF AGRICULTURAL AND FOOD CHEMISTRY 2018; 66:13444-13453. [PMID: 30488696 DOI: 10.1021/acs.jafc.8b05014] [Citation(s) in RCA: 21] [Impact Index Per Article: 3.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/21/2023]
Abstract
Resveratrol, a plant-derived polyphenolic compound with various health activities, is widely used in nutraceutical and food additives. Herein, combinatorial optimization of resveratrol biosynthetic pathway and intracellular environment of E. coli was carried out. By screening pathway genes from various species and exploring their expression pattern, we initially constructed resveratrol-producing strains. Further targeting at availability of malonyl-CoA through expressing ACC of Corynebacterium glutamicum and antisense inhibiting native fabD significantly increased resveratrol biosynthesis. Transport engineering for resveratrol secretion and molecular chaperones helping for folding heterologous enzymes were employed to improve the intracellular environments in remarkable degrees. By introducing PcTAL of Phanerochaete chrysosporium and tuning expression model of PcTAL, At4CL, and VvSTS, an engineered E. coli produced 57.77 mg/L of resveratrol from l-tyrosine. After integrating the above strategies, resveratrol titer reached to 238.71 mg/L from l-tyrosine. The combinatorial optimization in this study provides a promising strategy to produce valuable natural products in heterologous expression systems.
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Affiliation(s)
- Ying Zhao
- Department of Pharmaceutical Engineering, School of Chemical Engineering and Technology , Tianjin University , Tianjin 300350 , China
- Key Laboratory of Systems Bioengineering , Ministry of Education , Tianjin 300350 , China
- SynBio Research Platform , Collaborative Innovation Center of Chemical Science and Engineering , Tianjin 300350 , China
| | - Bi-Han Wu
- Department of Pharmaceutical Engineering, School of Chemical Engineering and Technology , Tianjin University , Tianjin 300350 , China
- Key Laboratory of Systems Bioengineering , Ministry of Education , Tianjin 300350 , China
- SynBio Research Platform , Collaborative Innovation Center of Chemical Science and Engineering , Tianjin 300350 , China
| | - Zhen-Ning Liu
- Department of Pharmaceutical Engineering, School of Chemical Engineering and Technology , Tianjin University , Tianjin 300350 , China
- Key Laboratory of Systems Bioengineering , Ministry of Education , Tianjin 300350 , China
- SynBio Research Platform , Collaborative Innovation Center of Chemical Science and Engineering , Tianjin 300350 , China
| | - Jianjun Qiao
- Department of Pharmaceutical Engineering, School of Chemical Engineering and Technology , Tianjin University , Tianjin 300350 , China
- Key Laboratory of Systems Bioengineering , Ministry of Education , Tianjin 300350 , China
- SynBio Research Platform , Collaborative Innovation Center of Chemical Science and Engineering , Tianjin 300350 , China
| | - Guang-Rong Zhao
- Department of Pharmaceutical Engineering, School of Chemical Engineering and Technology , Tianjin University , Tianjin 300350 , China
- Key Laboratory of Systems Bioengineering , Ministry of Education , Tianjin 300350 , China
- SynBio Research Platform , Collaborative Innovation Center of Chemical Science and Engineering , Tianjin 300350 , China
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Identification of active site residues implies a two-step catalytic mechanism for acyl-ACP thioesterase. Biochem J 2018; 475:3861-3873. [DOI: 10.1042/bcj20180470] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/17/2018] [Revised: 11/06/2018] [Accepted: 11/07/2018] [Indexed: 02/02/2023]
Abstract
In plants and bacteria that use a Type II fatty acid synthase, isozymes of acyl-acyl carrier protein (ACP) thioesterase (TE) hydrolyze the thioester bond of acyl-ACPs, terminating the process of fatty acid biosynthesis. These TEs are therefore critical in determining the fatty acid profiles produced by these organisms. Past characterizations of a limited number of plant-sourced acyl-ACP TEs have suggested a thiol-based, papain-like catalytic mechanism, involving a triad of Cys, His, and Asn residues. In the present study, the sequence alignment of 1019 plant and bacterial acyl-ACP TEs revealed that the previously proposed Cys catalytic residue is not universally conserved and therefore may not be a catalytic residue. Systematic mutagenesis of this residue to either Ser or Ala in three plant acyl-ACP TEs, CvFatB1 and CvFatB2 from Cuphea viscosissima and CnFatB2 from Cocos nucifera, resulted in enzymatically active variants, demonstrating that this Cys residue (Cys348 in CvFatB2) is not catalytic. In contrast, the multiple sequence alignment, together with the structure modeling of CvFatB2, suggests that the highly conserved Asp309 and Glu347, in addition to previously proposed Asn311 and His313, may be involved in catalysis. The substantial loss of catalytic competence associated with site-directed mutants at these positions confirmed the involvement of these residues in catalysis. By comparing the structures of acyl-ACP TE and the Pseudomonas 4-hydroxybenzoyl-CoA TE, both of which fold in the same hotdog tertiary structure and catalyze the hydrolysis reaction of thioester bond, we have proposed a two-step catalytic mechanism for acyl-ACP TE that involves an enzyme-bound anhydride intermediate.
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Fatty acid biosynthesis is enhanced in Escherichia coli strains with deletion in genes encoding the PII signaling proteins. Arch Microbiol 2018; 201:209-214. [PMID: 30506165 DOI: 10.1007/s00203-018-1603-2] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/29/2018] [Revised: 11/08/2018] [Accepted: 11/24/2018] [Indexed: 10/27/2022]
Abstract
The committed and rate-limiting step in fatty acid biosynthesis is catalyzed by acetyl-CoA carboxylase (ACC). In previous studies we showed that ACC activity is inhibited through interactions with the PII signaling proteins in vitro. Here we provide in vivo support for that model; we noted that PII proteins are able to reduce malonyl-CoA levels in vivo in Escherichia coli. Furthermore, we show that fatty acid biosynthesis is strongly enhanced in E. coli strains carrying deletions in PII coding genes. Given that PII proteins act as conserved negative regulators of ACC in Bacteria, our findings may be explored to engineer other prokaryotes to improve fatty acid yields, thereby turning microbial biofuel production economically competitive in the future.
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Hernández Lozada NJ, Lai RY, Simmons TR, Thomas KA, Chowdhury R, Maranas CD, Pfleger BF. Highly Active C 8-Acyl-ACP Thioesterase Variant Isolated by a Synthetic Selection Strategy. ACS Synth Biol 2018; 7:2205-2215. [PMID: 30064208 DOI: 10.1021/acssynbio.8b00215] [Citation(s) in RCA: 45] [Impact Index Per Article: 7.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/02/2023]
Abstract
Microbial metabolism is an attractive route for producing medium chain length fatty acids, e.g., octanoic acid, used in the oleochemical industry. One challenge to this strategy is the lack of enzymes that are both highly active in a microbial host and selective toward substrates with desired chain length. Of the many steps in fatty acid biosynthesis, the thioesterase is the most widely used enzyme for controlling chain length. Thioesterases hydrolyze the thioester bond between fatty acids and the acyl-carrier protein (ACP) or coenzyme A (CoA) cofactor. The functional role of thioesterases varies between organisms ( i.e., bacteria vs plant) and therefore so do the substrate specificities. As a result, microbial biocatalysts that utilize a heterologous thioesterase either produce high titers of fatty acids with mixed chain lengths or low titers of products with a narrow chain length distribution. To search for highly active enzymes that selectively hydrolyze octanoyl-ACP, we developed a genetic selection based on the lipoic acid requirement of Escherichia coli. We used the selection to identify variants in a randomly mutagenized library of the C8-specific Cuphea palustris FatB1 thioesterase. After optimizing expression of the thioesterase, E. coli cultures produced 1.7 g/L of octanoic acid with >90% specificity from a single chromosomal copy of this thioesterase. In vitro studies confirmed the mutant thioesterase possessed a 15-fold increase in kcat compared to its native sequence. The high level of specific activity allowed for low levels of expression while maintaining fatty acid titer. The low expression requirement will allow metabolic engineers to use more cellular resources to address other limitations in the pathway and maximize overall productivity.
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Affiliation(s)
- Néstor J. Hernández Lozada
- Department of Chemical and Biological Engineering, University of Wisconsin−Madison, 1415 Engineering Drive, Madison, Wisconsin 53706, United States
| | - Rung-Yi Lai
- Department of Chemical and Biological Engineering, University of Wisconsin−Madison, 1415 Engineering Drive, Madison, Wisconsin 53706, United States
| | - Trevor R. Simmons
- Department of Chemical and Biological Engineering, University of Wisconsin−Madison, 1415 Engineering Drive, Madison, Wisconsin 53706, United States
| | - Kelsey A. Thomas
- Department of Chemical and Biological Engineering, University of Wisconsin−Madison, 1415 Engineering Drive, Madison, Wisconsin 53706, United States
| | - Ratul Chowdhury
- Department of Chemical Engineering, Pennsylvania State University, 158 Fenske Laboratory, University Park, Pennsylvania 16802, United States
| | - Costas D. Maranas
- Department of Chemical Engineering, Pennsylvania State University, 158 Fenske Laboratory, University Park, Pennsylvania 16802, United States
| | - Brian F. Pfleger
- Department of Chemical and Biological Engineering, University of Wisconsin−Madison, 1415 Engineering Drive, Madison, Wisconsin 53706, United States
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Recent advances in metabolic engineering of Corynebacterium glutamicum for bioproduction of value-added aromatic chemicals and natural products. Appl Microbiol Biotechnol 2018; 102:8685-8705. [DOI: 10.1007/s00253-018-9289-6] [Citation(s) in RCA: 38] [Impact Index Per Article: 6.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/11/2018] [Revised: 07/30/2018] [Accepted: 07/31/2018] [Indexed: 02/06/2023]
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Hou J, Zheng H, Tzou WS, Cooper DR, Chruszcz M, Chordia MD, Kwon K, Grabowski M, Minor W. Differences in substrate specificity of V. cholerae FabH enzymes suggest new approaches for the development of novel antibiotics and biofuels. FEBS J 2018; 285:2900-2921. [PMID: 29917313 PMCID: PMC6105497 DOI: 10.1111/febs.14588] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/05/2018] [Revised: 05/31/2018] [Accepted: 06/15/2018] [Indexed: 01/14/2023]
Abstract
Vibrio cholerae, the causative pathogen of the life-threatening infection cholera, encodes two copies of β-ketoacyl-acyl carrier protein synthase III (vcFabH1 and vcFabH2). vcFabH1 and vcFabH2 are pathogenic proteins associated with fatty acid synthesis, lipid metabolism, and potential applications in biofuel production. Our biochemical assays characterize vcFabH1 as exhibiting specificity for acetyl-CoA and CoA thioesters with short acyl chains, similar to that observed for FabH homologs found in most gram-negative bacteria. vcFabH2 prefers medium chain-length acyl-CoA thioesters, particularly octanoyl-CoA, which is a pattern of specificity rarely seen in bacteria. Structural characterization of one vcFabH1 and six vcFabH2 structures determined in either apo form or in complex with acetyl-CoA/octanoyl-CoA indicate that the substrate-binding pockets of vcFabH1 and vcFabH2 are of different sizes, accounting for variations in substrate chain-length specificity. An unusual and unique feature of vcFabH2 is its C-terminal fragment that interacts with both the substrate-entrance loop and the dimer interface of the enzyme. Our discovery of the pattern of substrate specificity of both vcFabH1 and vcFabH2 can potentially aid the development of novel antibacterial agents against V. cholerae. Additionally, the distinctive substrate preference of FabH2 in V. cholerae and related facultative anaerobes conceivably make it an attractive component of genetically engineered bacteria used for commercial biofuel production.
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Affiliation(s)
- Jing Hou
- Department of Molecular Physiology and Biological Physics, University of Virginia, Charlottesville, VA 22908-0736, USA
- Center for Structural Genomics of Infectious Diseases (CSGID) Consortium, USA
| | - Heping Zheng
- Department of Molecular Physiology and Biological Physics, University of Virginia, Charlottesville, VA 22908-0736, USA
- Center for Structural Genomics of Infectious Diseases (CSGID) Consortium, USA
| | - Wen-Shyong Tzou
- Department of Molecular Physiology and Biological Physics, University of Virginia, Charlottesville, VA 22908-0736, USA
- Department of Bioscience and Biotechnology, National Taiwan Ocean University, Taiwan
| | - David R. Cooper
- Department of Molecular Physiology and Biological Physics, University of Virginia, Charlottesville, VA 22908-0736, USA
- Center for Structural Genomics of Infectious Diseases (CSGID) Consortium, USA
| | - Maksymilian Chruszcz
- Department of Chemistry and Biochemistry, University of South Carolina, Columbia, SC 29208, USA
| | - Mahendra D. Chordia
- Department of Molecular Physiology and Biological Physics, University of Virginia, Charlottesville, VA 22908-0736, USA
- Center for Structural Genomics of Infectious Diseases (CSGID) Consortium, USA
| | - Keehwan Kwon
- Center for Structural Genomics of Infectious Diseases (CSGID) Consortium, USA
- Infectious Diseases, J. Craig Venter Institute, Rockville, MD 20850, USA
| | - Marek Grabowski
- Department of Molecular Physiology and Biological Physics, University of Virginia, Charlottesville, VA 22908-0736, USA
- Center for Structural Genomics of Infectious Diseases (CSGID) Consortium, USA
| | - Wladek Minor
- Department of Molecular Physiology and Biological Physics, University of Virginia, Charlottesville, VA 22908-0736, USA
- Center for Structural Genomics of Infectious Diseases (CSGID) Consortium, USA
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Mehrer CR, Incha MR, Politz MC, Pfleger BF. Anaerobic production of medium-chain fatty alcohols via a β-reduction pathway. Metab Eng 2018; 48:63-71. [PMID: 29807110 DOI: 10.1016/j.ymben.2018.05.011] [Citation(s) in RCA: 40] [Impact Index Per Article: 6.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/15/2018] [Revised: 05/11/2018] [Accepted: 05/23/2018] [Indexed: 11/17/2022]
Abstract
In this report, we identify the relevant factors to increase production of medium chain n-alcohols through an expanded view of the reverse β-oxidation pathway. We began by creating a base strain capable of producing medium chain n-alcohols from glucose using a redox-balanced and growth-coupled metabolic engineering strategy. By dividing the heterologous enzymes in the pathway into different modules, we were able to identify and evaluate homologs of each enzyme within the pathway and identify several capable of enhancing medium chain alcohol titers and/or selectivity. In general, the identity of the trans-2-enoyl-CoA reductase (TER) and the direct overexpression of the thiolase (FadA) and β-hydroxy-acyl-CoA reductase (FadB) improved alcohol titer and the identity of the FadBA complex influenced the dominant chain length. Next, we linked the anaerobically induced VHb promoter from Vitreoscilla hemoglobin to each gene to remove the need for chemical inducers and ensure robust expression. The highest performing strain with the autoinduced reverse β-oxidation pathway produced n-alcohols at titers of 1.8 g/L with an apparent molar yield of 0.2 on glucose consumed in rich medium (52% of theoretical yield).
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Affiliation(s)
- Christopher R Mehrer
- Department of Chemical and Biological Engineering, University of Wisconsin-Madison, 3629 Engineering Hall, 1415 Engineering Drive, Madison, WI 53706, United States
| | - Matthew R Incha
- Department of Chemical and Biological Engineering, University of Wisconsin-Madison, 3629 Engineering Hall, 1415 Engineering Drive, Madison, WI 53706, United States
| | - Mark C Politz
- Department of Chemical and Biological Engineering, University of Wisconsin-Madison, 3629 Engineering Hall, 1415 Engineering Drive, Madison, WI 53706, United States
| | - Brian F Pfleger
- Department of Chemical and Biological Engineering, University of Wisconsin-Madison, 3629 Engineering Hall, 1415 Engineering Drive, Madison, WI 53706, United States; Microbiology Doctoral Training Program, University of Wisconsin-Madison, Madison, WI 53706, United States.
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The role of acyl-CoA thioesterase ACOT8I in mediating intracellular lipid metabolism in oleaginous fungus Mortierella alpina. ACTA ACUST UNITED AC 2018; 45:281-291. [DOI: 10.1007/s10295-018-2006-8] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/12/2017] [Accepted: 01/08/2018] [Indexed: 12/26/2022]
Abstract
Abstract
Thioesterases (TEs) play an essential role in the metabolism of fatty acids (FAs). To explore the role of TEs in mediating intracellular lipid metabolism in the oleaginous fungus Mortierella alpina, the acyl-CoA thioesterase ACOT8I was overexpressed. The contents of total fatty acids (TFAs) were the same in the recombinant strains as in the wild-type M. alpina, whilst the production of free fatty acids (FFAs) was enhanced from about 0.9% (wild-type) to 2.8% (recombinant), a roughly threefold increase. Linoleic acid content in FFA form constituted about 9% of the TFAs in the FFA fraction in the recombinant strains but only about 1.3% in the wild-type M. alpina. The gamma-linolenic acid and arachidonic acid contents in FFA form accounted for about 4 and 25%, respectively, of the TFAs in the FFA fraction in the recombinant strains, whilst neither of them in FFA form were detected in the wild-type M. alpina. Overexpression of the TE ACOT8I in the oleaginous fungus M. alpina reinforced the flux from acyl-CoAs to FFAs, improved the production of FFAs and tailored the FA profiles of the lipid species.
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Two distinct domains contribute to the substrate acyl chain length selectivity of plant acyl-ACP thioesterase. Nat Commun 2018; 9:860. [PMID: 29491418 PMCID: PMC5830452 DOI: 10.1038/s41467-018-03310-z] [Citation(s) in RCA: 22] [Impact Index Per Article: 3.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/07/2017] [Accepted: 02/01/2018] [Indexed: 01/12/2023] Open
Abstract
The substrate specificity of acyl-ACP thioesterase (TE) plays an essential role in controlling the fatty acid profile produced by type II fatty acid synthases. Here we identify two groups of residues that synergistically determine different substrate specificities of two acyl-ACP TEs from Cuphea viscosissima (CvFatB1 and CvFatB2). One group (V194, V217, N223, R226, R227, and I268 in CvFatB2) is critical in determining the structure and depth of a hydrophobic cavity in the N-terminal hotdog domain that binds the substrate's acyl moiety. The other group (255-RKLSKI-260 and 285-RKLPKL-289 in CvFatB2) defines positively charged surface patches that may facilitate binding of the ACP moiety. Mutagenesis of residues within these two groups results in distinct synthetic acyl-ACP TEs that efficiently hydrolyze substrates with even shorter chains (C4- to C8-ACPs). These insights into structural determinants of acyl-ACP TE substrate specificity are useful in modifying this enzyme for tailored fatty acid production in engineered organisms.
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