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Neves D, Meinen D, Alter TB, Blank LM, Ebert BE. Expanding Pseudomonas taiwanensis VLB120's acyl-CoA portfolio: Propionate production in mineral salt medium. Microb Biotechnol 2024; 17:e14309. [PMID: 37537795 PMCID: PMC10832534 DOI: 10.1111/1751-7915.14309] [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: 02/13/2023] [Revised: 06/06/2023] [Accepted: 06/25/2023] [Indexed: 08/05/2023] Open
Abstract
As one of the main precursors, acetyl-CoA leads to the predominant production of even-chain products. From an industrial biotechnology perspective, extending the acyl-CoA portfolio of a cell factory is vital to producing industrial relevant odd-chain alcohols, acids, ketones and polyketides. The bioproduction of odd-chain molecules can be facilitated by incorporating propionyl-CoA into the metabolic network. The shortest pathway for propionyl-CoA production, which relies on succinyl-CoA catabolism encoded by the sleeping beauty mutase operon, was evaluated in Pseudomonas taiwanensis VLB120. A single genomic copy of the sleeping beauty mutase genes scpA, argK and scpB combined with the deletion of the methylcitrate synthase PVLB_08385 was sufficient to observe propionyl-CoA accumulation in this Pseudomonas. The chassis' capability for odd-chain product synthesis was assessed by expressing an acyl-CoA hydrolase, which enabled propionate synthesis. Three fed-batch strategies during bioreactor fermentations were benchmarked for propionate production, in which a maximal propionate titre of 2.8 g L-1 was achieved. Considering that the fermentations were carried out in mineral salt medium under aerobic conditions and that a single genome copy drove propionyl-CoA production, this result highlights the potential of Pseudomonas to produce propionyl-CoA derived, odd-chain products.
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Affiliation(s)
- Dário Neves
- Institute of Applied Microbiology‐iAMB, Aachen Biology and Biotechnology‐ABBtRWTH Aachen UniversityAachenGermany
| | - Daniel Meinen
- Institute of Applied Microbiology‐iAMB, Aachen Biology and Biotechnology‐ABBtRWTH Aachen UniversityAachenGermany
| | - Tobias B. Alter
- Institute of Applied Microbiology‐iAMB, Aachen Biology and Biotechnology‐ABBtRWTH Aachen UniversityAachenGermany
| | - Lars M. Blank
- Institute of Applied Microbiology‐iAMB, Aachen Biology and Biotechnology‐ABBtRWTH Aachen UniversityAachenGermany
| | - Birgitta E. Ebert
- Institute of Applied Microbiology‐iAMB, Aachen Biology and Biotechnology‐ABBtRWTH Aachen UniversityAachenGermany
- Australian Institute for Bioengineering and Nanotechnology (AIBN)The University of QueenslandBrisbaneQueenslandAustralia
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2
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Kozaeva E, Nieto-Domínguez M, Hernández AD, Nikel PI. Synthetic metabolism for in vitro acetone biosynthesis driven by ATP regeneration. RSC Chem Biol 2022; 3:1331-1341. [PMID: 36349222 PMCID: PMC9627730 DOI: 10.1039/d2cb00170e] [Citation(s) in RCA: 4] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/22/2022] [Accepted: 09/15/2022] [Indexed: 05/14/2024] Open
Abstract
In vitro ketone production continues to be a challenge due to the biochemical features of the enzymes involved-even when some of them have been extensively characterized (e.g. thiolase from Clostridium acetobutylicum), the assembly of synthetic enzyme cascades still face significant limitations (including issues with protein aggregation and multimerization). Here, we designed and assembled a self-sustaining enzyme cascade with acetone yields close to the theoretical maximum using acetate as the only carbon input. The efficiency of this system was further boosted by coupling the enzymatic sequence to a two-step ATP-regeneration system that enables continuous, cost-effective acetone biosynthesis. Furthermore, simple methods were implemented for purifying the enzymes necessary for this synthetic metabolism, including a first-case example on the isolation of a heterotetrameric acetate:coenzyme A transferase by affinity chromatography.
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Affiliation(s)
- Ekaterina Kozaeva
- The Novo Nordisk Foundation Center for Biosustainability, Technical University of Denmark 2800 Kongens Lyngby Denmark +93 51 19 18
| | - Manuel Nieto-Domínguez
- The Novo Nordisk Foundation Center for Biosustainability, Technical University of Denmark 2800 Kongens Lyngby Denmark +93 51 19 18
| | - Abril D Hernández
- The Novo Nordisk Foundation Center for Biosustainability, Technical University of Denmark 2800 Kongens Lyngby Denmark +93 51 19 18
| | - Pablo I Nikel
- The Novo Nordisk Foundation Center for Biosustainability, Technical University of Denmark 2800 Kongens Lyngby Denmark +93 51 19 18
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3
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Kozaeva E, Mol V, Nikel PI, Nielsen AT. High-throughput colorimetric assays optimized for detection of ketones and aldehydes produced by microbial cell factories. Microb Biotechnol 2022; 15:2426-2438. [PMID: 35689383 PMCID: PMC9437884 DOI: 10.1111/1751-7915.14097] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/08/2022] [Accepted: 05/19/2022] [Indexed: 11/29/2022] Open
Abstract
Randomized strain and pathway engineering are critical to improving microbial cell factory performance, calling for the development of high‐throughput screening and selection systems. To facilitate this effort, we have developed two 96‐well plate format colorimetric assays for reliable quantification of various ketones and aldehydes from culture supernatants, based on either a vanillin‐acetone reaction or the 2,4‐dinitrophenylhydrazine (2,4‐DNPH) reagent. The vanillin‐acetone assay enabled accurate and selective measurement of acetone titers up to 2 g l−1 in a minimal culture medium. The 2,4‐DNPH‐based assay can be used for a wide range of aldehydes and ketones, shown here through the optimization of conditions for 15 different compounds. Both assays were implemented to improve acetone production from different substrates by an engineered Escherichia coli strain. The fast and user‐friendly colorimetric assays proposed here open the potential for iterative rounds of (automated) strain and pathway engineering and screening, facilitating the efforts towards further boosting production titers of industrially relevant ketones and aldehydes.
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Affiliation(s)
- Ekaterina Kozaeva
- The Novo Nordisk Foundation Center for Biosustainability, Technical University of Denmark, 2800, Kongens Lyngby, Denmark
| | - Viviënne Mol
- The Novo Nordisk Foundation Center for Biosustainability, Technical University of Denmark, 2800, Kongens Lyngby, Denmark
| | - Pablo I Nikel
- The Novo Nordisk Foundation Center for Biosustainability, Technical University of Denmark, 2800, Kongens Lyngby, Denmark
| | - Alex Toftgaard Nielsen
- The Novo Nordisk Foundation Center for Biosustainability, Technical University of Denmark, 2800, Kongens Lyngby, Denmark
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4
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Connolly JA, Harcombe WR, Smanski MJ, Kinkel LL, Takano E, Breitling R. Harnessing intercellular signals to engineer the soil microbiome. Nat Prod Rep 2021; 39:311-324. [PMID: 34850800 DOI: 10.1039/d1np00034a] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/11/2022]
Abstract
Covering: Focus on 2015 to 2020Plant and soil microbiomes consist of diverse communities of organisms from across kingdoms and can profoundly affect plant growth and health. Natural product-based intercellular signals govern important interactions between microbiome members that ultimately regulate their beneficial or harmful impacts on the plant. Exploiting these evolved signalling circuits to engineer microbiomes towards beneficial interactions with crops is an attractive goal. There are few reports thus far of engineering the intercellular signalling of microbiomes, but this article argues that it represents a tremendous opportunity for advancing the field of microbiome engineering. This could be achieved through the selection of synergistic consortia in combination with genetic engineering of signal pathways to realise an optimised microbiome.
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Affiliation(s)
- Jack A Connolly
- Manchester Institute of Biotechnology, Manchester Synthetic Biology Research Centre SYNBIOCHEM, Faculty of Science and Engineering, School of Natural Sciences, Department of Chemistry, The University of Manchester, Manchester, M1 7DN, UK.
| | - William R Harcombe
- BioTechnology Institute, University of Minnesota, Twin-Cities, Saint Paul, MN55108, USA.,Department of Evolution, and Behaviour, University of Minnesota, Twin-Cities Saint Paul, MN55108, USA
| | - Michael J Smanski
- BioTechnology Institute, University of Minnesota, Twin-Cities, Saint Paul, MN55108, USA.,Department of Biochemistry, Molecular Biology and Biophysics, University of Minnesota, Twin-Cities, Saint Paul, MN55108, USA
| | - Linda L Kinkel
- BioTechnology Institute, University of Minnesota, Twin-Cities, Saint Paul, MN55108, USA.,Department of Plant Pathology, University of Minnesota, Twin-Cities, Saint Paul, MN 55108, USA
| | - Eriko Takano
- Manchester Institute of Biotechnology, Manchester Synthetic Biology Research Centre SYNBIOCHEM, Faculty of Science and Engineering, School of Natural Sciences, Department of Chemistry, The University of Manchester, Manchester, M1 7DN, UK.
| | - Rainer Breitling
- Manchester Institute of Biotechnology, Manchester Synthetic Biology Research Centre SYNBIOCHEM, Faculty of Science and Engineering, School of Natural Sciences, Department of Chemistry, The University of Manchester, Manchester, M1 7DN, UK.
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5
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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: 81] [Impact Index Per Article: 27.0] [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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6
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C4 Bacterial Volatiles Improve Plant Health. Pathogens 2021; 10:pathogens10060682. [PMID: 34072921 PMCID: PMC8227687 DOI: 10.3390/pathogens10060682] [Citation(s) in RCA: 14] [Impact Index Per Article: 4.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/13/2021] [Revised: 05/10/2021] [Accepted: 05/24/2021] [Indexed: 02/04/2023] Open
Abstract
Plant growth-promoting rhizobacteria (PGPR) associated with plant roots can trigger plant growth promotion and induced systemic resistance. Several bacterial determinants including cell-wall components and secreted compounds have been identified to date. Here, we review a group of low-molecular-weight volatile compounds released by PGPR, which improve plant health, mostly by protecting plants against pathogen attack under greenhouse and field conditions. We particularly focus on C4 bacterial volatile compounds (BVCs), such as 2,3-butanediol and acetoin, which have been shown to activate the plant immune response and to promote plant growth at the molecular level as well as in large-scale field applications. We also disc/ uss the potential applications, metabolic engineering, and large-scale fermentation of C4 BVCs. The C4 bacterial volatiles act as airborne signals and therefore represent a new type of biocontrol agent. Further advances in the encapsulation procedure, together with the development of standards and guidelines, will promote the application of C4 volatiles in the field.
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7
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Fuji T, Nakazawa S, Ito K. Feasible-metabolic-pathway-exploration technique using chemical latent space. Bioinformatics 2021; 36:i770-i778. [PMID: 33381845 PMCID: PMC8454040 DOI: 10.1093/bioinformatics/btaa809] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/16/2022] Open
Abstract
Motivation Exploring metabolic pathways is one of the key techniques for developing highly
productive microbes for the bioproduction of chemical compounds. To explore feasible
pathways, not only examining a combination of well-known enzymatic reactions but also
finding potential enzymatic reactions that can catalyze the desired structural changes
are necessary. To achieve this, most conventional techniques use manually
predefined-reaction rules, however, they cannot sufficiently find potential reactions
because the conventional rules cannot comprehensively express structural changes before
and after enzymatic reactions. Evaluating the feasibility of the explored pathways is
another challenge because there is no way to validate the reaction possibility of
unknown enzymatic reactions by these rules. Therefore, a technique for comprehensively
capturing the structural changes in enzymatic reactions and a technique for evaluating
the pathway feasibility are still necessary to explore feasible metabolic pathways. Results We developed a feasible-pathway-exploration technique using chemical latent space
obtained from a deep generative model for compound structures. With this technique, an
enzymatic reaction is regarded as a difference vector between the main substrate and the
main product in chemical latent space acquired from the generative model. Features of
the enzymatic reaction are embedded into the fixed-dimensional vector, and it is
possible to express structural changes of enzymatic reactions comprehensively. The
technique also involves differential-evolution-based reaction selection to design
feasible candidate pathways and pathway scoring using neural-network-based
reaction-possibility prediction. The proposed technique was applied to the
non-registered pathways relevant to the production of 2-butanone, and successfully
explored feasible pathways that include such reactions.
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Affiliation(s)
- Taiki Fuji
- Center for Exploratory Research, Research and Development Group , Hitachi, Ltd., Kokubunji-shi, Tokyo 185-8601, Japan
| | - Shiori Nakazawa
- Center for Exploratory Research, Research and Development Group , Hitachi, Ltd., Kokubunji-shi, Tokyo 185-8601, Japan
| | - Kiyoto Ito
- Center for Exploratory Research, Research and Development Group , Hitachi, Ltd., Kokubunji-shi, Tokyo 185-8601, Japan
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8
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Miscevic D, Srirangan K, Kefale T, Kilpatrick S, Chung DA, Moo-Young M, Chou CP. Heterologous production of 3-hydroxyvalerate in engineered Escherichia coli. Metab Eng 2020; 61:141-151. [DOI: 10.1016/j.ymben.2019.11.005] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/06/2019] [Revised: 10/25/2019] [Accepted: 11/09/2019] [Indexed: 10/25/2022]
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9
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Orive-Milla N, Delmulle T, de Mey M, Faijes M, Planas A. Metabolic engineering for glycoglycerolipids production in E. coli: Tuning phosphatidic acid and UDP-glucose pathways. Metab Eng 2020; 61:106-119. [PMID: 32492511 DOI: 10.1016/j.ymben.2020.05.010] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/21/2019] [Revised: 05/04/2020] [Accepted: 05/25/2020] [Indexed: 12/12/2022]
Abstract
Glycolipids are target molecules in biotechnology and biomedicine as biosurfactants, biomaterials and bioactive molecules. An engineered E. coli strain for the production of glycoglycerolipids (GGL) used the MG517 glycolipid synthase from M. genitalium for glucosyl transfer from UDPGlc to diacylglycerol acceptor (Mora-Buyé et al., 2012). The intracellular diacylglycerol pool proved to be the limiting factor for GGL production. Here we designed different metabolic engineering strategies to enhance the availability of precursor substrates for the glycolipid synthase by modulating fatty acids, acyl donor and phosphatidic acid biosynthesis. Knockouts of tesA, fadE and fabR genes involved in fatty acids degradation, overexpression of the transcriptional regulator FadR, the acyltransferases PlsB and C, and the pyrophosphatase Cdh for phosphatidic acid biosynthesis, as well as the phosphatase PgpB for conversion to diacylglycerol were explored with the aim of improving GGL titers. Among the different engineered strains, the ΔtesA strain co-expressing MG517 and a fusion PlsCxPgpB protein was the best producer, with a 350% increase of GGL titer compared to the parental strain expressing MG517 alone. Attempts to boost UDPGlc availability by overexpressing the uridyltransferase GalU or knocking out the UDP-sugar diphosphatase encoding gene ushA did not further improve GGL titers. Most of the strains produced GGL containing a variable number of glucosyl units from mono-to tetra-saccharides. Interestingly, the strains co-expressing Cdh showed a shift in the GGL profile towards the diglucosylated lipid (up to 80% of total GGLs) whereas the strains with a fadR knockout presented a higher amount of unsaturated acyl chains. In all cases, GGL production altered the lipidic composition of the E. coli membrane, observing that GGL replace phosphatidylethanolamine to maintain the overall membrane charge balance.
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Affiliation(s)
- Nuria Orive-Milla
- Laboratory of Biochemistry, Institut Químic de Sarrià, University Ramon Llull, Via Augusta 350, E-08017, Barcelona, Spain
| | - Tom Delmulle
- Centre for Synthetic Biology (CSB), Ghent University, Coupure Links 653, B-9000, Ghent, Belgium
| | - Marjan de Mey
- Centre for Synthetic Biology (CSB), Ghent University, Coupure Links 653, B-9000, Ghent, Belgium
| | - Magda Faijes
- Laboratory of Biochemistry, Institut Químic de Sarrià, University Ramon Llull, Via Augusta 350, E-08017, Barcelona, Spain.
| | - Antoni Planas
- Laboratory of Biochemistry, Institut Químic de Sarrià, University Ramon Llull, Via Augusta 350, E-08017, Barcelona, Spain.
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10
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Yan Q, Simmons TR, Cordell WT, Hernández Lozada NJ, Breckner CJ, Chen X, Jindra MA, Pfleger BF. Metabolic engineering of β-oxidation to leverage thioesterases for production of 2-heptanone, 2-nonanone and 2-undecanone. Metab Eng 2020; 61:335-343. [PMID: 32479802 DOI: 10.1016/j.ymben.2020.05.008] [Citation(s) in RCA: 14] [Impact Index Per Article: 3.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/17/2020] [Revised: 05/15/2020] [Accepted: 05/19/2020] [Indexed: 01/06/2023]
Abstract
Medium-chain length methyl ketones are potential blending fuels due to their cetane numbers and low melting temperatures. Biomanufacturing offers the potential to produce these molecules from renewable resources such as lignocellulosic biomass. In this work, we designed and tested metabolic pathways in Escherichia coli to specifically produce 2-heptanone, 2-nonanone and 2-undecanone. We achieved substantial production of each ketone by introducing chain-length specific acyl-ACP thioesterases, blocking the β-oxidation cycle at an advantageous reaction, and introducing active β-ketoacyl-CoA thioesterases. Using a bioprospecting approach, we identified fifteen homologs of E. coli β-ketoacyl-CoA thioesterase (FadM) and evaluated the in vivo activity of each against various chain length substrates. The FadM variant from Providencia sneebia produced the most 2-heptanone, 2-nonanone, and 2-undecanone, suggesting it has the highest activity on the corresponding β-ketoacyl-CoA substrates. We tested enzyme variants, including acyl-CoA oxidases, thiolases, and bi-functional 3-hydroxyacyl-CoA dehydratases to maximize conversion of fatty acids to β-keto acyl-CoAs for 2-heptanone, 2-nonanone, and 2-undecanone production. In order to address the issue of product loss during fermentation, we applied a 20% (v/v) dodecane layer in the bioreactor and built an external water cooling condenser connecting to the bioreactor heat-transferring condenser coupling to the condenser. Using these modifications, we were able to generate up to 4.4 g/L total medium-chain length methyl ketones.
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Affiliation(s)
- Qiang Yan
- Department of Chemical and Biological Engineering, University of Wisconsin-Madison, Madison, WI, 53706, USA; DOE Center for Advanced Bioenergy and Bioproducts Innovation, University of Wisconsin-Madison, Madison, WI, 53706, USA.
| | - Trevor R Simmons
- Department of Chemical and Biological Engineering, University of Wisconsin-Madison, Madison, WI, 53706, USA
| | - William T Cordell
- Department of Chemical and Biological Engineering, University of Wisconsin-Madison, Madison, WI, 53706, USA; DOE Center for Advanced Bioenergy and Bioproducts Innovation, University of Wisconsin-Madison, Madison, WI, 53706, USA
| | - Néstor J Hernández Lozada
- Department of Chemical and Biological Engineering, University of Wisconsin-Madison, Madison, WI, 53706, USA
| | - Christian J Breckner
- Department of Chemical and Biological Engineering, University of Wisconsin-Madison, Madison, WI, 53706, USA
| | - Xuanqi Chen
- Department of Chemical and Biological Engineering, University of Wisconsin-Madison, Madison, WI, 53706, USA
| | - Michael A Jindra
- Department of Chemical and Biological Engineering, University of Wisconsin-Madison, Madison, WI, 53706, USA
| | - Brian F Pfleger
- Department of Chemical and Biological Engineering, University of Wisconsin-Madison, Madison, WI, 53706, USA; DOE Center for Advanced Bioenergy and Bioproducts Innovation, University of Wisconsin-Madison, Madison, WI, 53706, USA; Microbiology Doctoral Training Program, University of Wisconsin-Madison, Madison, WI, 53706, USA.
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11
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Ku JT, Chen AY, Lan EI. Metabolic Engineering Design Strategies for Increasing Acetyl-CoA Flux. Metabolites 2020; 10:metabo10040166. [PMID: 32340392 PMCID: PMC7240943 DOI: 10.3390/metabo10040166] [Citation(s) in RCA: 25] [Impact Index Per Article: 6.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/07/2020] [Revised: 04/19/2020] [Accepted: 04/21/2020] [Indexed: 01/18/2023] Open
Abstract
Acetyl-CoA is a key metabolite precursor for the biosynthesis of lipids, polyketides, isoprenoids, amino acids, and numerous other bioproducts which are used in various industries. Metabolic engineering efforts aim to increase carbon flux towards acetyl-CoA in order to achieve higher productivities of its downstream products. In this review, we summarize the strategies that have been implemented for increasing acetyl-CoA flux and concentration, and discuss their effects. Furthermore, recent works have developed synthetic acetyl-CoA biosynthesis routes that achieve higher stoichiometric yield of acetyl-CoA from glycolytic substrates.
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Affiliation(s)
- Jason T. Ku
- Institute of Molecular Medicine and Bioengineering, National Chiao Tung University, Hsinchu City 300, Taiwan; (J.T.K.); (A.Y.C.)
| | - Arvin Y. Chen
- Institute of Molecular Medicine and Bioengineering, National Chiao Tung University, Hsinchu City 300, Taiwan; (J.T.K.); (A.Y.C.)
| | - Ethan I. Lan
- Department of Biological Science and Technology, National Chiao Tung University, Hsinchu City 300, Taiwan
- Correspondence:
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12
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Integrated strain engineering and bioprocessing strategies for high-level bio-based production of 3-hydroxyvalerate in Escherichia coli. Appl Microbiol Biotechnol 2020; 104:5259-5272. [PMID: 32291486 DOI: 10.1007/s00253-020-10580-5] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/18/2019] [Revised: 03/15/2020] [Accepted: 03/23/2020] [Indexed: 12/12/2022]
Abstract
As petro-based production generates numerous environmental impacts and their associated technological concerns, bio-based production has been well recognized these days as a modern alternative to manufacture chemical products in a more renewable, environmentally friendly, and sustainable manner. Herein, we report the development of a microbial bioprocess for high-level and potentially economical production of 3-hydroxyvalerate (3-HV), a valuable special chemical with multiple applications in chemical, biopolymer, and pharmaceutical industries, from glycerol, which can be cheaply and renewably refined as a byproduct from biodiesel production. We used our recently derived 3-HV-producing Escherichia coli strains for bioreactor characterization under various culture conditions. In the parental strain, 3-HV biosynthesis was limited by the intracellular availability of propionyl-CoA, whose formation was favored by anaerobic conditions, which often compromised cell growth. With appropriate strain engineering, we demonstrated that 3-HV can be effectively produced under both microaerobic (close to anaerobic) and aerobic conditions, which determine the direction of dissimilated carbon flux toward the succinate node in the tricarboxylic acid (TCA) cycle. We first used the ∆sdhA single mutant strain, in which the dissimilated carbon flux was primarily directed to the Sleeping beauty mutase (Sbm) pathway (via the reductive TCA branch, with enhanced cell growth under microaerobic conditions, achieving 3.08 g L-1 3-HV in a fed-batch culture. In addition, we used the ∆sdhA-∆iclR double mutant strain, in which the dissimilated carbon flux was directed from the TCA cycle to the Sbm pathway via the deregulated glyoxylate shunt, for cultivation under rather aerobic conditions. In addition to demonstrating effective cell growth, this strain has shown impressive 3-HV biosynthesis (up to 10.6 g L-1), equivalent to an overall yield of 18.8% based on consumed glycerol, in aerobic fed-batch culture. This study not only represents one of the most effective bio-based production of 3-HV from structurally unrelated carbons to date, but also highlights the importance of integrated strain engineering and bioprocessing strategies to enhance bio-based production.Key points• TCA cycle engineering was applied to enhance 3-HV biosynthesis in E. coli. • Effects of oxygenic conditions on 3-HV in E. coli biosynthesis were investigated. • Bioreactor characterization of 3-HV biosynthesis in E. coli was performed.
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13
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Mar MJ, Andersen JM, Kandasamy V, Liu J, Solem C, Jensen PR. Synergy at work: linking the metabolism of two lactic acid bacteria to achieve superior production of 2-butanol. BIOTECHNOLOGY FOR BIOFUELS 2020; 13:45. [PMID: 32180827 PMCID: PMC7065357 DOI: 10.1186/s13068-020-01689-w] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Figures] [Subscribe] [Scholar Register] [Received: 12/11/2019] [Accepted: 02/26/2020] [Indexed: 06/10/2023]
Abstract
BACKGROUND The secondary alcohol 2-butanol has many important applications, e.g., as a solvent. Industrially, it is usually made by sulfuric acid-catalyzed hydration of butenes. Microbial production of 2-butanol has also been attempted, however, with little success as witnessed by the low titers and yields reported. Two important reasons for this, are the growth-hampering effect of 2-butanol on microorganisms, and challenges associated with one of the key enzymes involved in its production, namely diol dehydratase. RESULTS We attempt to link the metabolism of an engineered Lactococcus lactis strain, which possesses all enzyme activities required for fermentative production of 2-butanol from glucose, except for diol dehydratase, which acts on meso-2,3-butanediol (mBDO), with that of a Lactobacillus brevis strain which expresses a functional dehydratase natively. We demonstrate growth-coupled production of 2-butanol by the engineered L. lactis strain, when co-cultured with L. brevis. After fine-tuning the co-culture setup, a titer of 80 mM (5.9 g/L) 2-butanol, with a high yield of 0.58 mol/mol is achieved. CONCLUSIONS Here, we demonstrate that it is possible to link the metabolism of two bacteria to achieve redox-balanced production of 2-butanol. Using a simple co-cultivation setup, we achieved the highest titer and yield from glucose in a single fermentation step ever reported. The data highlight the potential that lies in harnessing microbial synergies for producing valuable compounds.
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Affiliation(s)
- Mette J. Mar
- National Food Institute, Technical University of Denmark, Kemitorvet, Building 201, 2800 Kgs. Lyngby, Denmark
| | - Joakim M. Andersen
- National Food Institute, Technical University of Denmark, Kemitorvet, Building 201, 2800 Kgs. Lyngby, Denmark
| | - Vijayalakshmi Kandasamy
- National Food Institute, Technical University of Denmark, Kemitorvet, Building 201, 2800 Kgs. Lyngby, Denmark
| | - Jianming Liu
- National Food Institute, Technical University of Denmark, Kemitorvet, Building 201, 2800 Kgs. Lyngby, Denmark
| | - Christian Solem
- National Food Institute, Technical University of Denmark, Kemitorvet, Building 201, 2800 Kgs. Lyngby, Denmark
| | - Peter R. Jensen
- National Food Institute, Technical University of Denmark, Kemitorvet, Building 201, 2800 Kgs. Lyngby, Denmark
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14
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Miscevic D, Mao JY, Moo-Young M, Chou CHP. High-level heterologous production of propionate in engineered Escherichia coli. Biotechnol Bioeng 2020; 117:1304-1315. [PMID: 31956980 DOI: 10.1002/bit.27276] [Citation(s) in RCA: 8] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/28/2019] [Revised: 01/13/2020] [Accepted: 01/16/2020] [Indexed: 12/14/2022]
Abstract
A propanologenic (i.e., 1-propanol-producing) bacterium Escherichia coli strain was previously derived by activating the genomic sleeping beauty mutase (Sbm) operon. The activated Sbm pathway branches out of the tricarboxylic acid (TCA) cycle at the succinyl-CoA node to form propionyl-CoA and its derived metabolites of 1-propanol and propionate. In this study, we targeted several TCA cycle genes encoding enzymes near the succinyl-CoA node for genetic manipulation to identify the individual contribution of the carbon flux into the Sbm pathway from the three TCA metabolic routes, that is, oxidative TCA cycle, reductive TCA branch, and glyoxylate shunt. For the control strain CPC-Sbm, in which propionate biosynthesis occurred under relatively anaerobic conditions, the carbon flux into the Sbm pathway was primarily derived from the reductive TCA branch, and both succinate availability and the SucCD-mediated interconversion of succinate/succinyl-CoA were critical for such carbon flux redirection. Although the oxidative TCA cycle normally had a minimal contribution to the carbon flux redirection, the glyoxylate shunt could be an alternative and effective carbon flux contributor under aerobic conditions. With mechanistic understanding of such carbon flux redirection, metabolic strategies based on blocking the oxidative TCA cycle (via ∆sdhA mutation) and deregulating the glyoxylate shunt (via ∆iclR mutation) were developed to enhance the carbon flux redirection and therefore propionate biosynthesis, achieving a high propionate titer of 30.9 g/L with an overall propionate yield of 49.7% upon fed-batch cultivation of the double mutant strain CPC-Sbm∆sdhA∆iclR under aerobic conditions. The results also suggest that the Sbm pathway could be metabolically active under both aerobic and anaerobic conditions.
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Affiliation(s)
- Dragan Miscevic
- Department of Chemical Engineering, University of Waterloo, Waterloo, Ontario, Canada
| | - Ju-Yi Mao
- Department of Bioscience and Biotechnology, National Taiwan Ocean University, Keelung, Taiwan
| | - Murray Moo-Young
- Department of Chemical Engineering, University of Waterloo, Waterloo, Ontario, Canada
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15
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Westbrook AW, Miscevic D, Kilpatrick S, Bruder MR, Moo-Young M, Chou CP. Strain engineering for microbial production of value-added chemicals and fuels from glycerol. Biotechnol Adv 2019; 37:538-568. [DOI: 10.1016/j.biotechadv.2018.10.006] [Citation(s) in RCA: 26] [Impact Index Per Article: 5.2] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/16/2017] [Revised: 10/03/2018] [Accepted: 10/10/2018] [Indexed: 12/22/2022]
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16
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Abstract
Reduced polyketides are a subclass of natural products that have a variety of medical, veterinary, and agricultural applications and are well known for their structural diversity. Although these compounds do not resemble each other, they are all made by a class of enzymes known as modular polyketide synthases (PKSs). The commonality of PKS domains/modules that compose PKSs and the understanding of the relationship between the sequence of the PKS and the structure of the compound it produces render modular PKSs as excellent targets for engineering to produce novel compounds with predicted structures. Here, we describe experimental protocols and considerations for modular PKS engineering and two case studies to produce commodity chemicals by engineered PKSs.
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17
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Escherichia coli as a host for metabolic engineering. Metab Eng 2018; 50:16-46. [DOI: 10.1016/j.ymben.2018.04.008] [Citation(s) in RCA: 181] [Impact Index Per Article: 30.2] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/17/2018] [Revised: 04/11/2018] [Accepted: 04/12/2018] [Indexed: 12/21/2022]
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18
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Yuzawa S, Mirsiaghi M, Jocic R, Fujii T, Masson F, Benites VT, Baidoo EEK, Sundstrom E, Tanjore D, Pray TR, George A, Davis RW, Gladden JM, Simmons BA, Katz L, Keasling JD. Short-chain ketone production by engineered polyketide synthases in Streptomyces albus. Nat Commun 2018; 9:4569. [PMID: 30385744 PMCID: PMC6212451 DOI: 10.1038/s41467-018-07040-0] [Citation(s) in RCA: 34] [Impact Index Per Article: 5.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/03/2018] [Accepted: 09/26/2018] [Indexed: 01/14/2023] Open
Abstract
Microbial production of fuels and commodity chemicals has been performed primarily using natural or slightly modified enzymes, which inherently limits the types of molecules that can be produced. Type I modular polyketide synthases (PKSs) are multi-domain enzymes that can produce unique and diverse molecular structures by combining particular types of catalytic domains in a specific order. This catalytic mechanism offers a wealth of engineering opportunities. Here we report engineered microbes that produce various short-chain (C5-C7) ketones using hybrid PKSs. Introduction of the genes into the chromosome of Streptomyces albus enables it to produce >1 g · l-1 of C6 and C7 ethyl ketones and several hundred mg · l-1 of C5 and C6 methyl ketones from plant biomass hydrolysates. Engine tests indicate these short-chain ketones can be added to gasoline as oxygenates to increase the octane of gasoline. Together, it demonstrates the efficient and renewable microbial production of biogasolines by hybrid enzymes.
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Affiliation(s)
- Satoshi Yuzawa
- Biogical Systems and Engineering Division, Lawrence Berkeley National Laboratory, Berkeley, California, 94720, United States. .,Joint BioEnegy Institute, Emeryville, California, 94608, United States. .,Biotechnology Research Center, The University of Tokyo, Tokyo, 113-8657, Japan.
| | - Mona Mirsiaghi
- Biogical Systems and Engineering Division, Lawrence Berkeley National Laboratory, Berkeley, California, 94720, United States.,Advanced Biofuels & Bioproducts Process Development Unit, Lawrence Berkeley National Laboratory, Berkeley, California, 94720, United States
| | - Renee Jocic
- Biogical Systems and Engineering Division, Lawrence Berkeley National Laboratory, Berkeley, California, 94720, United States
| | - Tatsuya Fujii
- Joint BioEnegy Institute, Emeryville, California, 94608, United States.,Research Institute for Sustainable Chemistry, Institute for Synthetic Biology, National Institute of Advanced Industrial Science and Technology, Higashi-hiroshima, Hiroshima, 739-0046, Japan
| | - Fabrice Masson
- Biogical Systems and Engineering Division, Lawrence Berkeley National Laboratory, Berkeley, California, 94720, United States.,Advanced Biofuels & Bioproducts Process Development Unit, Lawrence Berkeley National Laboratory, Berkeley, California, 94720, United States
| | - Veronica T Benites
- Biogical Systems and Engineering Division, Lawrence Berkeley National Laboratory, Berkeley, California, 94720, United States.,Joint BioEnegy Institute, Emeryville, California, 94608, United States
| | - Edward E K Baidoo
- Biogical Systems and Engineering Division, Lawrence Berkeley National Laboratory, Berkeley, California, 94720, United States.,Joint BioEnegy Institute, Emeryville, California, 94608, United States
| | - Eric Sundstrom
- Biogical Systems and Engineering Division, Lawrence Berkeley National Laboratory, Berkeley, California, 94720, United States.,Advanced Biofuels & Bioproducts Process Development Unit, Lawrence Berkeley National Laboratory, Berkeley, California, 94720, United States
| | - Deepti Tanjore
- Biogical Systems and Engineering Division, Lawrence Berkeley National Laboratory, Berkeley, California, 94720, United States.,Advanced Biofuels & Bioproducts Process Development Unit, Lawrence Berkeley National Laboratory, Berkeley, California, 94720, United States
| | - Todd R Pray
- Biogical Systems and Engineering Division, Lawrence Berkeley National Laboratory, Berkeley, California, 94720, United States.,Advanced Biofuels & Bioproducts Process Development Unit, Lawrence Berkeley National Laboratory, Berkeley, California, 94720, United States
| | - Anthe George
- Joint BioEnegy Institute, Emeryville, California, 94608, United States.,Department of Biomass Science and Conversion Technologies, Sandia National Laboratory, Livermore, California, 94551, United States
| | - Ryan W Davis
- Department of Biomass Science and Conversion Technologies, Sandia National Laboratory, Livermore, California, 94551, United States
| | - John M Gladden
- Joint BioEnegy Institute, Emeryville, California, 94608, United States.,Department of Biomass Science and Conversion Technologies, Sandia National Laboratory, Livermore, California, 94551, United States
| | - Blake A Simmons
- Biogical Systems and Engineering Division, Lawrence Berkeley National Laboratory, Berkeley, California, 94720, United States.,Joint BioEnegy Institute, Emeryville, California, 94608, United States
| | - Leonard Katz
- Joint BioEnegy Institute, Emeryville, California, 94608, United States.,QB3 Institute, University of California, Berkeley, California, 94720, United States
| | - Jay D Keasling
- Biogical Systems and Engineering Division, Lawrence Berkeley National Laboratory, Berkeley, California, 94720, United States. .,Joint BioEnegy Institute, Emeryville, California, 94608, United States. .,QB3 Institute, University of California, Berkeley, California, 94720, United States. .,Department of Bioengineering, University of California, Berkeley, California, 94720, United States. .,Department of Chemical and Biomolecular Engineering, University of California, Berkeley, California, 94720, United States. .,Novo Nordisk Foundation Center for Biosustainability, Technical University of Denmark, Building 220, Kemitorvet, DK-2800, Kgs, Lyngby, Denmark. .,Center for Synthetic Biochemistry, Shenzhen Institutes for Advanced Technologies, Shenzhen, Guangdong, 518055, China.
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19
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Tokic M, Hadadi N, Ataman M, Neves D, Ebert BE, Blank LM, Miskovic L, Hatzimanikatis V. Discovery and Evaluation of Biosynthetic Pathways for the Production of Five Methyl Ethyl Ketone Precursors. ACS Synth Biol 2018; 7:1858-1873. [PMID: 30021444 DOI: 10.1021/acssynbio.8b00049] [Citation(s) in RCA: 22] [Impact Index Per Article: 3.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/22/2022]
Abstract
The limited supply of fossil fuels and the establishment of new environmental policies shifted research in industry and academia toward sustainable production of the second generation of biofuels, with methyl ethyl ketone (MEK) being one promising fuel candidate. MEK is a commercially valuable petrochemical with an extensive application as a solvent. However, as of today, a sustainable and economically viable production of MEK has not yet been achieved despite several attempts of introducing biosynthetic pathways in industrial microorganisms. We used BNICE.ch as a retrobiosynthesis tool to discover all novel pathways around MEK. Out of 1325 identified compounds connecting to MEK with one reaction step, we selected 3-oxopentanoate, but-3-en-2-one, but-1-en-2-olate, butylamine, and 2-hydroxy-2-methylbutanenitrile for further study. We reconstructed 3 679 610 novel biosynthetic pathways toward these 5 compounds. We then embedded these pathways into the genome-scale model of E. coli, and a set of 18 622 were found to be the most biologically feasible ones on the basis of thermodynamics and their yields. For each novel reaction in the viable pathways, we proposed the most similar KEGG reactions, with their gene and protein sequences, as candidates for either a direct experimental implementation or as a basis for enzyme engineering. Through pathway similarity analysis we classified the pathways and identified the enzymes and precursors that were indispensable for the production of the target molecules. These retrobiosynthesis studies demonstrate the potential of BNICE.ch for discovery, systematic evaluation, and analysis of novel pathways in synthetic biology and metabolic engineering studies.
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Affiliation(s)
- Milenko Tokic
- Laboratory of Computational Systems Biotechnology (LCSB), Swiss Federal Institute of Technology (EPFL), CH-1015 Lausanne, Switzerland
| | - Noushin Hadadi
- Laboratory of Computational Systems Biotechnology (LCSB), Swiss Federal Institute of Technology (EPFL), CH-1015 Lausanne, Switzerland
| | - Meric Ataman
- Laboratory of Computational Systems Biotechnology (LCSB), Swiss Federal Institute of Technology (EPFL), CH-1015 Lausanne, Switzerland
| | - Dário Neves
- Institute of Applied Microbiology (iAMB), Aachen Biology and Biotechnology (ABBt), RWTH Aachen University, D-52056 Aachen, Germany
| | - Birgitta E. Ebert
- Institute of Applied Microbiology (iAMB), Aachen Biology and Biotechnology (ABBt), RWTH Aachen University, D-52056 Aachen, Germany
| | - Lars M. Blank
- Institute of Applied Microbiology (iAMB), Aachen Biology and Biotechnology (ABBt), RWTH Aachen University, D-52056 Aachen, Germany
| | - Ljubisa Miskovic
- Laboratory of Computational Systems Biotechnology (LCSB), Swiss Federal Institute of Technology (EPFL), CH-1015 Lausanne, Switzerland
| | - Vassily Hatzimanikatis
- Laboratory of Computational Systems Biotechnology (LCSB), Swiss Federal Institute of Technology (EPFL), CH-1015 Lausanne, Switzerland
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20
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van Beek HL, Romero E, Fraaije MW. Engineering Cyclohexanone Monooxygenase for the Production of Methyl Propanoate. ACS Chem Biol 2017; 12:291-299. [PMID: 27935281 DOI: 10.1021/acschembio.6b00965] [Citation(s) in RCA: 21] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022]
Abstract
A previous study showed that cyclohexanone monooxygenase from Acinetobacter calcoaceticus (AcCHMO) catalyzes the Baeyer-Villiger oxidation of 2-butanone, yielding ethyl acetate and methyl propanoate as products. Methyl propanoate is of industrial interest as a precursor of acrylic plastic. Here, various residues near the substrate and NADP+ binding sites in AcCHMO were subjected to saturation mutagenesis to enhance both the activity on 2-butanone and the regioselectivity toward methyl propanoate. The resulting libraries were screened using whole cell biotransformations, and headspace gas chromatography-mass spectrometry was used to identify improved AcCHMO variants. This revealed that the I491A AcCHMO mutant exhibits a significant improvement over the wild type enzyme in the desired regioselectivity using 2-butanone as a substrate (40% vs 26% methyl propanoate, respectively). Another interesting mutant is the T56S AcCHMO mutant, which exhibits a higher conversion yield (92%) and kcat (0.5 s-1) than wild type AcCHMO (52% and 0.3 s-1, respectively). Interestingly, the uncoupling rate for the T56S AcCHMO mutant is also significantly lower than that for the wild type enzyme. The T56S/I491A double mutant combined the beneficial effects of both mutations leading to higher conversion and improved regioselectivity. This study shows that even for a relatively small aliphatic substrate (2-butanone), catalytic efficiency and regioselectivity can be tuned by structure-inspired enzyme engineering.
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Affiliation(s)
- Hugo L. van Beek
- Molecular Enzymology Group, University of Groningen, Nijenborgh 4, 9747AG Groningen, The Netherlands
| | - Elvira Romero
- Molecular Enzymology Group, University of Groningen, Nijenborgh 4, 9747AG Groningen, The Netherlands
| | - Marco W. Fraaije
- Molecular Enzymology Group, University of Groningen, Nijenborgh 4, 9747AG Groningen, The Netherlands
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21
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Srirangan K, Liu X, Tran TT, Charles TC, Moo-Young M, Chou CP. Engineering of Escherichia coli for direct and modulated biosynthesis of poly(3-hydroxybutyrate-co-3-hydroxyvalerate) copolymer using unrelated carbon sources. Sci Rep 2016; 6:36470. [PMID: 27819347 PMCID: PMC5098226 DOI: 10.1038/srep36470] [Citation(s) in RCA: 20] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/19/2016] [Accepted: 10/14/2016] [Indexed: 12/13/2022] Open
Abstract
While poly(3-hydroxybutyrate-co-3-hydroxyvalerate) [P(3HB-co-3HV)] is a biodegradable commodity plastic with broad applications, its microbial synthesis is hindered by high production costs primarily associated with the supplementation of related carbon substrates (e.g. propionate or valerate). Here we report construction of engineered Escherichia coli strains for direct synthesis of P(3HB-co-3HV) from an unrelated carbon source (e.g. glucose or glycerol). First, an E. coli strain with an activated sleeping beauty mutase (Sbm) operon was used to generate propionyl-CoA as a precursor. Next, two acetyl-CoA moieties or acetyl-CoA and propionyl-CoA were condensed to form acetoacetyl-CoA and 3-ketovaleryl-CoA, respectively, by functional expression of β-ketothiolases from Cupriavidus necator (i.e. PhaA and BktB). The resulting thioester intermediates were channeled into the polyhydroxyalkanoate (PHA) biosynthetic pathway through functional expression of acetoacetyl-CoA reductase (PhaB) for thioester reduction and PHA synthase (PhaC) for subsequent polymerization. Metabolic engineering of E. coli host strains was further conducted to enhance total PHA content and the 3-hydroxyvaleryl (3HV) monomer fraction in the copolymer. Using a selection of engineered E. coli strains for batch cultivation with an unrelated carbon source, we achieved high-level P(3HB-co-3HV) production with the 3HV monomer fraction ranging from 3 to 19 mol%, demonstrating the potential industrial applicability of these whole-cell biocatalysts.
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Affiliation(s)
- Kajan Srirangan
- Department of Chemical Engineering , University of Waterloo, 200 University Avenue West Waterloo, Ontario N2L 3G1 Canada
| | - Xuejia Liu
- Department of Chemical Engineering , University of Waterloo, 200 University Avenue West Waterloo, Ontario N2L 3G1 Canada
| | - Tam T Tran
- Department of Biology, University of Waterloo, Waterloo, Ontario, Canada
| | - Trevor C Charles
- Department of Biology, University of Waterloo, Waterloo, Ontario, Canada
| | - Murray Moo-Young
- Department of Chemical Engineering , University of Waterloo, 200 University Avenue West Waterloo, Ontario N2L 3G1 Canada
| | - C Perry Chou
- Department of Chemical Engineering , University of Waterloo, 200 University Avenue West Waterloo, Ontario N2L 3G1 Canada
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22
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Srirangan K, Bruder M, Akawi L, Miscevic D, Kilpatrick S, Moo-Young M, Chou CP. Recent advances in engineering propionyl-CoA metabolism for microbial production of value-added chemicals and biofuels. Crit Rev Biotechnol 2016; 37:701-722. [PMID: 27557613 DOI: 10.1080/07388551.2016.1216391] [Citation(s) in RCA: 9] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [Key Words] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/21/2022]
Abstract
Diminishing fossil fuel reserves and mounting environmental concerns associated with petrochemical manufacturing practices have generated significant interests in developing whole-cell biocatalytic systems for the production of value-added chemicals and biofuels. Although acetyl-CoA is a common natural biogenic precursor for the biosynthesis of numerous metabolites, propionyl-CoA is unpopular and non-native to most organisms. Nevertheless, with its C3-acyl moiety as a discrete building block, propionyl-CoA can serve as another key biogenic precursor to several biological products of industrial importance. As a result, engineering propionyl-CoA metabolism, particularly in genetically tractable hosts with the use of inexpensive feedstocks, has paved an avenue for novel biomanufacturing. Herein, we present a systematic review on manipulation of propionyl-CoA metabolism as well as relevant genetic and metabolic engineering strategies for microbial production of value-added chemicals and biofuels, including odd-chain alcohols and organic acids, bio(co)polymers and polyketides. [Formula: see text].
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Affiliation(s)
| | - Mark Bruder
- a Department of Chemical Engineering , University of Waterloo , Waterloo , ON , Canada
| | - Lamees Akawi
- a Department of Chemical Engineering , University of Waterloo , Waterloo , ON , Canada
| | - Dragan Miscevic
- a Department of Chemical Engineering , University of Waterloo , Waterloo , ON , Canada
| | - Shane Kilpatrick
- a Department of Chemical Engineering , University of Waterloo , Waterloo , ON , Canada
| | - Murray Moo-Young
- a Department of Chemical Engineering , University of Waterloo , Waterloo , ON , Canada
| | - C Perry Chou
- a Department of Chemical Engineering , University of Waterloo , Waterloo , ON , Canada
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