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

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.