Zhang Bo, Wang Ying, Niu Kun, Liu Zhiqiang, Zheng Yuguo
The National and Local Joint Engineering Research Center for Biomanufacturing of Chiral Chemicals, Zhejiang University of Technology, Hangzhou 310014, Zhejiang, China.
Key Laboratory of Bioorganic Synthesis of Zhejiang Province, College of Biotechnology and Bioengineering, Zhejiang University of Technology, Hangzhou 310014, Zhejiang, China.
Sheng Wu Gong Cheng Xue Bao. 2023 Aug 25;39(8):3302-3317. doi: 10.13345/j.cjb.230138.
L-methionine, also known as L-aminomethane, is one of the eight essential amino acids required by the human body and has important applications in the fields of feed, medicine, and food. In this study, an L-methionine high-yielding strain was constructed using a modular metabolic engineering strategy based on the M2 strain ( W3110 ΔIJAHFEBC/PAM) previously constructed in our laboratory. Firstly, the production of one-carbon module methyl donors was enhanced by overexpression of methylenetetrahydrofolate reductase (methylenetetrahydrofolate reductase, MetF) and screening of hydroxymethyltransferase (GlyA) from different sources, optimizing the one-carbon module. Subsequently, cysteamine lyase (hydroxymethyltransferase, MalY) and cysteine internal transporter gene () were overexpressed to improve the supply of L-homocysteine and L-cysteine, two precursors of the one-carbon module. The production of L-methionine in shake flask fermentation was increased from 2.8 g/L to 4.05 g/L, and up to 18.26 g/L in a 5 L fermenter. The results indicate that the one carbon module has a significant impact on the biosynthesis of L-methionine, and efficient biosynthesis of L-methionine can be achieved through optimizing the one carbon module. This study may facilitate further improvement of microbial fermentation production of L-methionine.
L-甲硫氨酸，又称L-氨基丁烷，是人体所需的八种必需氨基酸之一，在饲料、医药和食品领域有重要应用。本研究基于本实验室先前构建的M2菌株（W3110ΔIJAHFEBC/PAM），采用模块化代谢工程策略构建了一株L-甲硫氨酸高产菌株。首先，通过过表达亚甲基四氢叶酸还原酶（MetF）和筛选不同来源的羟甲基转移酶（GlyA）来增强一碳模块甲基供体的产生，优化一碳模块。随后，过表达半胱胺裂解酶（羟甲基转移酶，MalY）和半胱氨酸内部转运基因（），以改善一碳模块的两种前体L-高半胱氨酸和L-半胱氨酸的供应。摇瓶发酵中L-甲硫氨酸的产量从2.8 g/L提高到4.05 g/L，在5 L发酵罐中高达18.26 g/L。结果表明，一碳模块对L-甲硫氨酸的生物合成有显著影响，通过优化一碳模块可实现L-甲硫氨酸的高效生物合成。本研究可能有助于进一步提高微生物发酵生产L-甲硫氨酸的水平。
