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Diao M, Chen X, Li J, Shi Y, Yu B, Ma Z, Li J, Xie N. Metabolic Engineering of Escherichia coli for High-Level Production of ( R)-Acetoin from Low-Cost Raw Materials. Microorganisms 2023; 11:microorganisms11010203. [PMID: 36677495 PMCID: PMC9867144 DOI: 10.3390/microorganisms11010203] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/19/2022] [Revised: 01/09/2023] [Accepted: 01/10/2023] [Indexed: 01/15/2023] Open
Abstract
Acetoin is an important four-carbon platform chemical with versatile applications. Optically pure (R)-acetoin is more valuable than the racemate as it can be applied in the asymmetric synthesis of optically active α-hydroxy ketone derivatives, pharmaceuticals, and liquid crystal composites. As a cytotoxic solvent, acetoin at high concentrations severely limits culture performance and impedes the acetoin yield of cell factories. In this study, putative genes that may improve the resistance to acetoin for Escherichia coli were screened. To obtain a high-producing strain, the identified acetoin-resistance gene was overexpressed, and the synthetic pathway of (R)-acetoin was strengthened by optimizing the copy number of the key genes. The engineered E. coli strain GXASR-49RSF produced 81.62 g/L (R)-acetoin with an enantiomeric purity of 96.5% in the fed-batch fermentation using non-food raw materials in a 3-L fermenter. Combining the systematic approach developed in this study with the use of low-cost feedstock showed great potential for (R)-acetoin production via this cost-effective biotechnological process.
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Affiliation(s)
- Mengxue Diao
- State Key Laboratory of Non-Food Biomass and Enzyme Technology, National Engineering Research Center for Non-Food Biorefinery, Guangxi Biomass Engineering Technology Research Center, Guangxi Academy of Sciences, 98 Daling Road, Nanning 530007, China
- Correspondence: (M.D.); (N.X.)
| | - Xianrui Chen
- State Key Laboratory of Non-Food Biomass and Enzyme Technology, National Engineering Research Center for Non-Food Biorefinery, Guangxi Biomass Engineering Technology Research Center, Guangxi Academy of Sciences, 98 Daling Road, Nanning 530007, China
| | - Jing Li
- State Key Laboratory for Conservation and Utilization of Subtropical Agro-Bioresources, Life Science and Technology College, Guangxi University, Nanning 530004, China
| | - Ya’nan Shi
- CAS Key Laboratory of Microbial Physiological & Metabolic Engineering, Institute of Microbiology, Chinese Academy of Sciences, Beijing 100101, China
| | - Bo Yu
- CAS Key Laboratory of Microbial Physiological & Metabolic Engineering, Institute of Microbiology, Chinese Academy of Sciences, Beijing 100101, China
| | - Zhilin Ma
- State Key Laboratory for Conservation and Utilization of Subtropical Agro-Bioresources, Life Science and Technology College, Guangxi University, Nanning 530004, China
| | - Jianxiu Li
- State Key Laboratory of Non-Food Biomass and Enzyme Technology, National Engineering Research Center for Non-Food Biorefinery, Guangxi Biomass Engineering Technology Research Center, Guangxi Academy of Sciences, 98 Daling Road, Nanning 530007, China
| | - Nengzhong Xie
- State Key Laboratory of Non-Food Biomass and Enzyme Technology, National Engineering Research Center for Non-Food Biorefinery, Guangxi Biomass Engineering Technology Research Center, Guangxi Academy of Sciences, 98 Daling Road, Nanning 530007, China
- Correspondence: (M.D.); (N.X.)
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Bae SJ, Kim S, Park HJ, Kim J, Jin H, Kim BG, Hahn JS. High-yield production of (R)-acetoin in Saccharomyces cerevisiae by deleting genes for NAD(P)H-dependent ketone reductases producing meso-2,3-butanediol and 2,3-dimethylglycerate. Metab Eng 2021; 66:68-78. [PMID: 33845171 DOI: 10.1016/j.ymben.2021.04.001] [Citation(s) in RCA: 9] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/05/2020] [Revised: 02/19/2021] [Accepted: 04/04/2021] [Indexed: 01/09/2023]
Abstract
Acetoin is widely used in food and cosmetics industries as a taste and fragrance enhancer. To produce (R)-acetoin in Saccharomyces cerevisiae, acetoin biosynthetic genes encoding α-acetolactate synthase (AlsS) and α-acetolactate decarboxylase (AlsD) from Bacillus subtilis and water-forming NADH oxidase (NoxE) from Lactococcus lactis were integrated into delta-sequences in JHY605 strain, where the production of ethanol, glycerol, and (R,R)-2,3-butanediol (BDO) was largely eliminated. We further improved acetoin production by increasing acetoin tolerance by adaptive laboratory evolution, and eliminating other byproducts including meso-2,3-BDO and 2,3-dimethylglycerate, a newly identified byproduct. Ara1, Ypr1, and Ymr226c (named Ora1) were identified as (S)-alcohol-forming reductases, which can reduce (R)-acetoin to meso-2,3-BDO in vitro. However, only Ara1 and Ypr1 contributed to meso-2,3-BDO production in vivo. We elucidate that Ora1, having a substrate preference for (S)-acetoin, reduces (S)-α-acetolactate to 2,3-dimethylglycerate, thus competing with AlsD-mediated (R)-acetoin production. By deleting ARA1, YPR1, and ORA1, 101.3 g/L of (R)-acetoin was produced with a high yield (96% of the maximum theoretical yield) and high stereospecificity (98.2%).
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Affiliation(s)
- Sang-Jeong Bae
- School of Chemical and Biological Engineering, Institute of Chemical Processes, Seoul National University, 1 Gwanak-ro, Gwanak-gu, Seoul, 08826, Republic of Korea
| | - Sujin Kim
- School of Chemical and Biological Engineering, Institute of Chemical Processes, Seoul National University, 1 Gwanak-ro, Gwanak-gu, Seoul, 08826, Republic of Korea
| | - Hyun June Park
- Department of Biotechnology, Duksung Women's University, 33 Samyang-ro 144-gil, Dobong-gu, Seoul, 01369, Republic of Korea
| | - Joonwon Kim
- School of Chemical and Biological Engineering, Institute of Chemical Processes, Seoul National University, 1 Gwanak-ro, Gwanak-gu, Seoul, 08826, Republic of Korea
| | - Hyunbin Jin
- School of Chemical and Biological Engineering, Institute of Chemical Processes, Seoul National University, 1 Gwanak-ro, Gwanak-gu, Seoul, 08826, Republic of Korea
| | - Byung-Gee Kim
- School of Chemical and Biological Engineering, Institute of Chemical Processes, Seoul National University, 1 Gwanak-ro, Gwanak-gu, Seoul, 08826, Republic of Korea
| | - Ji-Sook Hahn
- School of Chemical and Biological Engineering, Institute of Chemical Processes, Seoul National University, 1 Gwanak-ro, Gwanak-gu, Seoul, 08826, Republic of Korea.
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Jia X, Kelly RM, Han Y. Simultaneous biosynthesis of ( R)-acetoin and ethylene glycol from D-xylose through in vitro metabolic engineering. Metab Eng Commun 2018; 7:e00074. [PMID: 30197863 PMCID: PMC6127078 DOI: 10.1016/j.mec.2018.e00074] [Citation(s) in RCA: 10] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/02/2018] [Revised: 06/18/2018] [Accepted: 06/24/2018] [Indexed: 11/28/2022] Open
Abstract
(R)-acetoin is a four-carbon platform compound used as the precursor for synthesizing novel optically active materials. Ethylene glycol (EG) is a large-volume two-carbon commodity chemical used as the anti-freezing agent and building-block molecule for various polymers. Currently established microbial fermentation processes for converting monosaccharides to either (R)-acetoin or EG are plagued by the formation of undesirable by-products. We show here that a cell-free bioreaction scheme can generate enantiomerically pure acetoin and EG as co-products from biomass-derived D-xylose. The seven-step, ATP-free system included in situ cofactor regeneration and recruited enzymes from Escherichia coli W3110, Bacillus subtilis shaijiu 32 and Caulobacter crescentus CB 2. Optimized in vitro biocatalytic conditions generated 3.2 mM (R)-acetoin with stereoisomeric purity of 99.5% from 10 mM D-xylose at 30 °C and pH 7.5 after 24 h, with an initial (R)-acetoin productivity of 1.0 mM/h. Concomitantly, EG was produced at 5.5 mM, with an initial productivity of 1.7 mM/h. This in vitro biocatalytic platform illustrates the potential for production of multiple value-added biomolecules from biomass-based sugars with no ATP requirement.
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Key Words
- (R)-acetoin
- BSA, bovine serum albumin
- Cofactor regeneration
- D-xylose
- EG, ethylene glycol
- EMP, Embden-Meyerhoff-Parnas
- Ethylene glycol
- FAD, flavin adenine dinucleotide
- GC, gas chromatography
- HPLC, high-pressure liquid chromatography
- IPTG, isopropyl-β-D-thiogalactopyranoside
- In vitro metabolic engineering
- LB, lysogeny broth
- NAD+, oxidized nicotinamide adenine dinucleotide
- NADH, reduced nicotinamide adenine dinucleotide
- PET, polyethylene terephthalate
- PP, pentose phosphate
- SDS-PAGE, sodium dodecyl sulfate-polyacrylamide gel electrophoresis
- ThDP, Thiamine diphosphate
- ee, enantiomeric excess
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Affiliation(s)
- Xiaojing Jia
- National Key Laboratory of Biochemical Engineering, Institute of Process Engineering, Chinese Academy of Sciences, Beijing 100190, China
- University of Chinese Academy of Sciences, Beijing 100049, China
| | - Robert M. Kelly
- Department of Chemical and Biomolecular Engineering North Carolina State University, Raleigh, NC 27695-7905, USA
| | - Yejun Han
- National Key Laboratory of Biochemical Engineering, Institute of Process Engineering, Chinese Academy of Sciences, Beijing 100190, China
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