谷氨酸棒杆菌S9114摇瓶发酵产γ-氨基丁酸的研究

Research of gamma aminobutyric acid production by Corynebacterium glutamicum S9114 in shaking flask

为实现谷氨酸棒杆菌工业化生产γ-氨基丁酸(GABA),对L-谷氨酸工业生产菌S9114进行代谢途径改造。通过构建一株工程菌株S9114/p JYW-4-gad B1-gad B2,将来源于短乳杆菌Lb85菌株的谷氨酸脱羧酶编码基因gad B1和gad B2进行共表达,实现发酵72 h后发酵液中GABA含量达到32.8 g/L,GABA糖酸转化率达到47.3%。通过敲除该菌株的谷丙转氨酶编码基因ala T,使工程菌株S9114Δala T/p JYW-4-gad B1-gad B2发酵液中L-丙氨酸浓度降低5.5%,进一步降低了发酵副产物的含量。研究结果为利用谷氨酸棒杆菌实现工业化生产γ-氨基丁酸提供了有价值的参考。

In order to produce gamma-aminobutyric acid （GABA） by Corynebacterium glutamicum, metabolic engineering of GABA in recombinant C. glutamicum S9114 was investigated. By expressing exogenous gad genes （gadB1 and gadB2） from Lactobacillus brevis Lb85 which encoded glutamic acid decarboxylase （GAD）, S9114/pJYW-4-gadBl-gadB2 was constructed. After fermented for 72 h, GABA production was 32.8 g/L and the conversion rate of glucose to GABA was 46.3%. By deleting alaT which encoded alanine aminotransferase, S9114△alaT/pJYW-4-gadBl-gadB2 was constructed. Fermentation results showed that the L-alanine production in S9114△alaT/pJYW-4-gadB1-gadB2 was 5.5% lower than that in S9114/pJYW-4-gadB1-gadB2, which further reduced the content of the by-products. This study provided a valuable basis for the industrialized production of GABA by C. glutamicum.