Extracellular expression of glutamate decarboxylase B in Escherichia coli to improve gamma-aminobutyric acid production.
Extracellular expression of glutamate decarboxylase B in Escherichia coli to improve gamma-aminobutyric acid production.
复制标题
大肠杆菌中谷氨酸脱羧酶 B 的胞外表达可提高 γ-氨基丁酸的产量
DOI：
10.1186/s13568-016-0231-y
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发表时间：
2016-12
期刊：
影响因子：
3.7
通讯作者：
Wang X
中科院分区：
文献类型：
--
作者：
Zhao A;Hu X;Li Y;Chen C;Wang X
过量表达谷氨酸脱羧酶GadB的大肠杆菌可以在添加谷氨酸的情况下产生γ-氨基丁酸。如果在大肠杆菌中过量表达GadB，可能会显著提高γ-氨基丁酸的产量和生产能力。大肠杆菌细胞可以排泄到外面，在那里它可以直接将谷氨酸转化为γ-氨基丁酸。在本研究中，GadB分别与信号肽TorA或PelB融合，并在E. coli BL21（DE3）。发现TorA比PelB更能促进GadB分泌。对大肠杆菌GadB分泌和γ-氨基丁酸产生的条件进行了优化。coliBL 21（DE 3）/pET 20 b-torA-gadB，使GadB的过表达量达到半数以上。在一个发酵罐中依次进行用于GadB表达和γ-氨基丁酸生产的BL 21（DE 3）/pET 20 b-torA-gadB的补料分批发酵;在36和72 h后分别获得264.4和313.1 g/L的γ-氨基丁酸。
Escherichia coli overexpressing glutamate decarboxylase GadB can produce gamma-aminobutyric acid with addition of monosodium glutamate. The yield and productivity of gamma-aminobutyric acid might be significantly improved if the overexpressed GadB in E. coli cells can be excreted outside, where it can directly transforms monosodium glutamate to gamma-aminobutyric acid. In this study, GadB was fused to signal peptides TorA or PelB, respectively, and overexpressed in E. coli BL21(DE3). It was found that TorA could facilitate GadB secretion much better than PelB. Conditions for GadB secretion and gamma-aminobutyric acid production were optimized in E. coli BL21(DE3)/pET20b-torA-gadB, leading the secretion of more than half of the overexpressed GadB. Fed-batch fermentation for GadB expression and gamma-aminobutyric acid production of BL21(DE3)/pET20b-torA-gadB was sequentially performed in one fermenter; 264.4 and 313.1 g/L gamma-aminobutyric acid were obtained with addition of monosodium glutamate after 36 and 72 h, respectively.