1
|
Xu JM, Li JQ, Zhang B, Liu ZQ, Zheng YG. Fermentative production of the unnatural amino acid L-2-aminobutyric acid based on metabolic engineering. Microb Cell Fact 2019; 18:43. [PMID: 30819198 PMCID: PMC6393993 DOI: 10.1186/s12934-019-1095-z] [Citation(s) in RCA: 15] [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] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/03/2019] [Accepted: 02/25/2019] [Indexed: 01/13/2023] Open
Abstract
Background l-2-aminobutyric acid (l-ABA) is an unnatural amino acid that is a key intermediate for the synthesis of several important pharmaceuticals. To make the biosynthesis of l-ABA environmental friendly and more suitable for the industrial-scale production. We expand the nature metabolic network of Escherichia coli using metabolic engineering approach for the production of l-ABA. Results In this study, Escherichia coli THR strain with a modified pathway for threonine-hyperproduction was engineered via deletion of the rhtA gene from the chromosome. To redirect carbon flux from 2-ketobutyrate (2-KB) to l-ABA, the ilvIH gene was deleted to block the l-isoleucine pathway. Furthermore, the ilvA gene from Escherichia coli W3110 and the leuDH gene from Thermoactinomyces intermedius were amplified and co-overexpressed. The promoter was altered to regulate the expression strength of ilvA* and leuDH. The final engineered strain E. coli THR ΔrhtAΔilvIH/Gap-ilvA*-Pbs-leuDH was able to produce 9.33 g/L of l-ABA with a yield of 0.19 g/L/h by fed-batch fermentation in a 5 L bioreactor. Conclusions This novel metabolically tailored strain offers a promising approach to fulfill industrial requirements for production of l-ABA. Electronic supplementary material The online version of this article (10.1186/s12934-019-1095-z) contains supplementary material, which is available to authorized users.
Collapse
Affiliation(s)
- Jian-Miao Xu
- Key Laboratory of Bioorganic Synthesis of Zhejiang Province, College of Biotechnology and Bioengineering, Zhejiang University of Technology, Hangzhou, 310014, China
| | - Jian-Qiang Li
- Key Laboratory of Bioorganic Synthesis of Zhejiang Province, College of Biotechnology and Bioengineering, Zhejiang University of Technology, Hangzhou, 310014, China
| | - Bo Zhang
- Key Laboratory of Bioorganic Synthesis of Zhejiang Province, College of Biotechnology and Bioengineering, Zhejiang University of Technology, Hangzhou, 310014, China
| | - Zhi-Qiang Liu
- Key Laboratory of Bioorganic Synthesis of Zhejiang Province, College of Biotechnology and Bioengineering, Zhejiang University of Technology, Hangzhou, 310014, China.
| | - Yu-Guo Zheng
- Key Laboratory of Bioorganic Synthesis of Zhejiang Province, College of Biotechnology and Bioengineering, Zhejiang University of Technology, Hangzhou, 310014, China
| |
Collapse
|
2
|
Wang Y, Li GS, Qiao P, Lin L, Xue HL, Zhu L, Wu MB, Lin JP, Yang LR. Increased productivity of L-2-aminobutyric acid and total turnover number of NAD +/NADH in a one-pot system through enhanced thermostability of L-threonine deaminase. Biotechnol Lett 2018; 40:1551-1559. [PMID: 30259222 DOI: 10.1007/s10529-018-2607-3] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/02/2018] [Accepted: 09/17/2018] [Indexed: 11/29/2022]
Abstract
OBJECTIVE To strengthen NADH regeneration in the biosynthesis of L-2-aminobutyric acid (L-ABA). RESULTS L-Threonine deaminase (L-TD) from Escherichia coli K12 was modified by directed evolution and rational design to improve its endurance to heat treatment. The half-life of mutant G323D/F510L/T344A at 42 °C increased from 10 to 210 min, a 20-fold increase compared to the wild-type L-TD, and the temperature at which the activity of the enzyme decreased by 50% in 15 min increased from 39 to 53 °C. The mutant together with thermostable L-leucine dehydrogenase from Bacillus sphaericus DSM730 and formate dehydrogenase from Candida boidinii constituted a one-pot system for L-ABA biosynthesis. Employing preheat treatment in the one-pot system, the biosynthesis of L-ABA and total turnover number of NAD+/NADH were 0.993 M and 16,469, in contrast to 0.635 M and 10,531 with wild-type L-TD, respectively. CONCLUSIONS By using the engineered L-TD during endured preheat treatment, the one-pot system has achieved a higher productivity of L-ABA and total turnover number of coenzyme.
Collapse
Affiliation(s)
- Ying Wang
- Key Laboratory of Biomass Chemical Engineering of Ministry of Education, College of Chemical and Biological Engineering, Zhejiang University, 38 Zhe-da Road, Hangzhou, 310007, Zhejiang, People's Republic of China
| | - Guo-Si Li
- Key Laboratory of Biomass Chemical Engineering of Ministry of Education, College of Chemical and Biological Engineering, Zhejiang University, 38 Zhe-da Road, Hangzhou, 310007, Zhejiang, People's Republic of China
| | - Pei Qiao
- Key Laboratory of Biomass Chemical Engineering of Ministry of Education, College of Chemical and Biological Engineering, Zhejiang University, 38 Zhe-da Road, Hangzhou, 310007, Zhejiang, People's Republic of China
| | - Ling Lin
- Key Laboratory of Biomass Chemical Engineering of Ministry of Education, College of Chemical and Biological Engineering, Zhejiang University, 38 Zhe-da Road, Hangzhou, 310007, Zhejiang, People's Republic of China
| | - Hai-Long Xue
- Key Laboratory of Biomass Chemical Engineering of Ministry of Education, College of Chemical and Biological Engineering, Zhejiang University, 38 Zhe-da Road, Hangzhou, 310007, Zhejiang, People's Republic of China
| | - Li Zhu
- Key Laboratory of Biomass Chemical Engineering of Ministry of Education, College of Chemical and Biological Engineering, Zhejiang University, 38 Zhe-da Road, Hangzhou, 310007, Zhejiang, People's Republic of China
| | - Mian-Bin Wu
- Key Laboratory of Biomass Chemical Engineering of Ministry of Education, College of Chemical and Biological Engineering, Zhejiang University, 38 Zhe-da Road, Hangzhou, 310007, Zhejiang, People's Republic of China
| | - Jian-Ping Lin
- Key Laboratory of Biomass Chemical Engineering of Ministry of Education, College of Chemical and Biological Engineering, Zhejiang University, 38 Zhe-da Road, Hangzhou, 310007, Zhejiang, People's Republic of China.
| | - Li-Rong Yang
- Key Laboratory of Biomass Chemical Engineering of Ministry of Education, College of Chemical and Biological Engineering, Zhejiang University, 38 Zhe-da Road, Hangzhou, 310007, Zhejiang, People's Republic of China
| |
Collapse
|