Engineering Escherichia coli to improve tryptophan production via genetic manipulation of precursor and cofactor pathways  

作　　者：Zhu Li Dongqin Ding Huiying Wang Linxia Liu Huan Fang Tao Chen Dawei Zhang 

机构地区：[1]Key Laboratory of Systems Bioengineering of the Ministry of Education,School of Chemical Engineering and Technology,SynBio Research Platform,Collaborative Innovation Centre of Chemical Science and Engineering,Tianjin University,Tianjin,300072,China [2]Key Laboratory of Systems Microbial Biotechnology,Chinese Academy of Sciences,Tianjin,300308,China [3]Tianjin Institute of Industrial Biotechnology,Chinese Academy of Sciences,Tianjin,300308,China [4]University of Chinese Academy of Sciences,Beijing,100049,China

出　　处：《Synthetic and Systems Biotechnology》2020年第3期200-205,共6页合成和系统生物技术（英文）

基　　金：This work was supported by the National Key R&D Program of China(2018YFA0900300);the Tianjin Science Fund for Distinguished Young Scholars(17JCJQJC45300);the Science and Technology Service Network(STS)Initiative of the Chinese Academy of Sciences(CAS)(KFJ-STS-ZDTP-065).

摘　　要：Optimizing the supply of biosynthetic precursors and cofactors is usually an effective metabolic strategy to improve the production of target compounds.Here,the combination of optimizing precursor synthesis and balancing cofactor metabolism was adopted to improve tryptophan production in Escherichia coli.First,glutamine synthesis was improved by expressing heterologous glutamine synthetase from Bacillus subtilis and Bacillus megaterium in the engineered Escherichia coli strain KW001,resulting in the best candidate strain TS-1.Then icd and gdhA were overexpressed in TS-1,which led to the accumulation of 1.060 g/L tryptophan.Subsequently,one more copy of prs was introduced on the chromosome to increase the flux of 5-phospho-α-D-ribose 1-diphosphate followed by the expression of mutated serA and thrA to increase the precursor supply of serine,resulting in the accumulation of 1.380 g/L tryptophan.Finally,to maintain cofactor balance,sthA and pntAB,encoding transhydrogenase,were overexpressed.With sufficient amounts of precursors and balanced cofactors,the engineered strain could produce 1.710 g/L tryptophan after 48 h of shake-flask fermentation,which was 2.76-times higher than the titer of the parent strain.Taken together,our results demonstrate that the combination of optimizing precursor supply and regulating cofactor metabolism is an effective approach for high-level production of tryptophan.Similar strategies could be applied to the production of other amino acids or related derivatives.

关 键 词：Escherichia coli TRYPTOPHAN Metabolic precursors Cofactor supply 

分 类 号：Q819[生物学—生物工程]