丝氨酸脱氨酶酶法拆分DL-丝氨酸

利用pET28a为载体在宿主细胞BL21(DE3)中重组表达了大肠杆菌丝氨酸脱氨酶,以L-丝氨酸为底物,研究了其酶学性质,考察了温度、起始pH、底物质量浓度等因素对酶促反应的影响,并利用丝氨酸脱氨酶酶法拆分了DL-丝氨酸。结果表明,丝氨酸脱氨酶重组表达成功;丝氨酸脱氨酶最佳反应条件为37℃,pH=9.0,底物质量浓度40 g/L;0.3 g菌体细胞酶法拆分100 mLρ(DL-丝氨酸)=80 g/L反应液需8 h,其中,L-丝氨酸摩尔转化率达98%。

Enzymatic resolution of DL-serine with recombinant serine deaminase activity

The serine deaminase from Escherichia coli K-12 MG1655 was recombinantly expressed in Escherichia coli BL21(DE3) using plasmid pET28a as vector.The enzymatic properties of the recombinant serine deaminase were studied,and several influencing factors of the enzyme reaction,such as temperature,initial pH,concentration of L-serine,were investigated.Then,DL-serine was resolved with recombinant serine deaminase.The results indicate that the recombinant serine deaminase was successfully expressed,and the optimal conditions for the enzymatic conversion of L-serine were 37 ℃,initial pH=9.0 and ρ(L-serine)=40 g/L.The enzymatic resolution of 100 mL ρ(DL-serine)=80 g/L with 0.3 g serine deaminase cell needed 8 h,and the mole conversion rate of L-serine was up to 98%.