Lyu Chang-Jiang, Zhao Wei-Rui, Hu Sheng, Huang Jun, Lu Tao, Jin Zhi-Hua, Mei Le-He, Yao Shan-Jing
College of Chemical and Biological Engineering, Zhejiang University , Hangzhou 310027, China.
School of Biotechnology and Chemical Engineering, Ningbo Institute of Technology, Zhejiang University , Ningbo 315100, China.
J Agric Food Chem. 2017 Feb 1;65(4):858-866. doi: 10.1021/acs.jafc.6b04442. Epub 2017 Jan 18.
Gamma-aminobutyrate (GABA) is an important chemical in the pharmaceutical field. GABA-producing lactic acid bacteria (LAB) offer the opportunity of developing this health-oriented product. In this study, the gadA, gadB, gadC, gadCB, and gadCA gene segments of Lactobacillus brevis were cloned into pMG36e, and strain Lb. brevis/pMG36e-gadA was selected for thorough characterization in terms of GABA production after analysis of GAD activities. Subsequently, a physiology-oriented engineering strategy was adopted to construct an FF-ATPase deficient strain NRA6 with higher GAD activity. As expected, strain NRA6 could produce GABA at a concentration of 43.65 g/L with a 98.42% GABA conversion rate in GYP fermentation medium, which is 1.22-fold higher than that obtained by the wild-type strain in the same condition. This work demonstrates how the acid stress response mechanisms of LAB can be employed to develop cell factories with improved production efficiency and contributes to research into the development of the physiology-oriented engineering.
γ-氨基丁酸（GABA）是制药领域一种重要的化学物质。产GABA的乳酸菌为开发这种健康导向型产品提供了契机。在本研究中，短乳杆菌的gadA、gadB、gadC、gadCB和gadCA基因片段被克隆到pMG36e中，在分析谷氨酸脱羧酶（GAD）活性后，选择短乳杆菌/pMG36e-gadA菌株进行GABA生产方面的全面表征。随后，采用一种面向生理学的工程策略构建了具有更高GAD活性的FF-ATP酶缺陷型菌株NRA6。不出所料，在GYP发酵培养基中，菌株NRA6能够以43.65 g/L的浓度生产GABA，GABA转化率为98.42%，这比相同条件下野生型菌株的产量高1.22倍。这项工作展示了如何利用乳酸菌的酸应激反应机制来开发生产效率更高的细胞工厂，并有助于面向生理学的工程开发研究。
