1株酪氨酸脱羧酶产生菌的构建及其诱导条件优化

Construction of one Tyrosine Decarboxylase-producing Strain and the Optimization of Its Induction Conditions

摘要: 通过酪氨酸脱羧酶(TDC)催化L-酪氨酸脱羧生成酪胺,是一种低成本、高效、绿色制备酪氨的方法。利用pBAD/His为载体在宿主细胞 E.coli BL21-AI(DE3)中表达了短乳杆菌来源的TDC,构建基因工程菌E.coli BL21-AI(DE3)-tdc,并对该菌L-阿拉伯糖诱导表达的条件进行优化。结果表明:在26℃培养6 h后加入终浓度为1.0 g·L^-1的L-阿拉伯糖诱导表达8 h,TDC酶活达183.2 U·g^-1;在5 L发酵罐进行放大,TDC酶活达到192 U·g^-1,菌体最高湿重为18.2 g·L^-1,相对于摇瓶发酵的1.92 g·L^-1增长了8.47倍。

Abstract: L-tyrosine decarboxylation catalyzed by tyrosine decarboxylase (TDC) to produce tyramine, is a low-cost, efficient, green preparation method to produce tyrosine. The TDC derived from Lactobacillus brevis was expressed in the host cell of E.coli BL21-AI (DE3) by using the pBAD/His vector, and the genetically engineered bacteria E.coli BL21-AI(DE3)-tdc was constructed, and the conditions of L-arabinose induced expression of the strain were optimized. The results showed that the enzyme activity of TDC reached 183.2 U·g^-1 after the induced expression with 1.0 g·L^-1 L-arabinose at 26℃ for 6 h. The TDC activity reached 192 U·g^-1 and the maximum wet weight of bacteria was18.2 g·L^-1, which was 8.47 times higher than that in the shaking flask fermentation, being 1.92 g·L^-1.