High-level production of𝛾γ-aminobutyric acid via efficient co-expression of the key genes of glutamate decarboxylase system in Escherichia coli  

作　　者：Lili Yao Changjiang Lyu Yuting Wang Sheng Hu Weirui Zhao Hongwei Cao Jun Huang Lehe Mei 

机构地区：[1]College of Life Science and Technology,Heilongjiang Bayi Agricultural University,Daqing 163319,China [2]School of Biological and Chemical Engineering,Zhejiang University of Science and Technology,Hangzhou 310023,China [3]School of Biological and Chemical Engineering,Ningbo Tech University,Ningbo 315100,China [4]College of Chemical and Biological Engineering,Zhejiang University,Hangzhou 310027,China

出　　处：《Engineering Microbiology》2023年第2期65-71,共7页工程微生物学（英文）

基　　金：This work was supported by Natural Science Foundation of Zhe-jiang Province(LY23B060001);Zhejiang Provincial Key R&D Pro-gram of China(2021C02049);China Postdoctoral Science Founda-tion(2020M671337);National Natural Science Foundation of China(31670804,31971372);Ningbo"Scientific and Technological In-novation 2025″Key Project(2020Z080,2020Z088).

摘　　要：Biosynthesis of the functional factor𝛾γ-aminobutyric acid(GABA)in bacteria involves two key proteins an intra-cellular glutamate decarboxylase(GadB)and a membrane-bound antiporter(GadC).Efficient co-expression of suitable GadB and GadC candidates is crucial for improving GABA productivity.In this study,gadBΔC11 of Lacti-plantibacillus plantarum and gadCΔC41 of Escherichia coli were inserted into the designed double promoter(P T7lac and P BAD)expression system.Then,E.coli Lemo21(DE3)was chosen as the host to minimize the toxic effects of GadCΔC41 overexpression.Furthermore,a green and high-efficiency GABA synthesis system using dormant engineered Lemo21(DE3)cells as biocatalysts was developed.The total GABA yield reached 829.08 g/L with a 98.7%conversion ratio within 13 h,when engineered E.coli Lemo21(DE3)cells were concentrated to an OD 600 of 20 and reused for three cycles in a 3 M L-glutamate solution at 37℃,which represented the highest GABA productivity ever reported.Overall,expanding the active pH ranges of GadB and GadC toward physiological pH and employing a tunable expression host for membrane-bound GadC production is a promising strategy for high-level GABA biosynthesis in E.coli.

关 键 词：Glutamate decarboxylase ANTIPORTER γ-Aminobutyric acid E.COLI Whole-cell biocatalysts 

分 类 号：O64[理学—物理化学]