共表达烟酸转磷酸核糖激酶和丙酮酸羧化酶对大肠杆菌NZN111产丁二酸的影响

Effects of co-expression of nicotinic acid phosphoribosyltransferase and pyruvate carboxylase on succinic acid production in Escherichia coli NZN111

构建了共表达烟酸转磷酸核糖激酶(NAPRTase)和丙酮酸羧化酶(PYC)的重组质粒pTrc99a-pncB-pyc,并考察了重组菌E.coli NZN111/pTrc99a-pncB-pyc生产丁二酸的能力。结果表明:重组菌NZN111/pTrc99a-pncB-pyc的NAPRTase和PYC的比酶活达到最高,分别为20.75和1.04 U/mg,同时,辅酶NADH、NAD+及NAD(H)总量达到最高。厌氧摇瓶发酵结果:48 h能够消耗17.5 g/L的葡萄糖生成14.08 g/L的丁二酸,而丙酮酸的产量大幅度降低,仅为0.11 g/L。本研究为基因工程菌大肠杆菌厌氧条件下发酵生产丁二酸提供了一定的基础。

The recombinant plasmid pTrc99a-pncB-pyc, co-expressing nicotinic acid phosphoribosy ltransferase （ NAPRTase ） and pyruvate carboxylase （ PYC ） , was constructed and the capability of succinic acid production in E. coli NZN111/pTrc99a-pncB-pyc was investigated. The results showed that the specific enzyme activities of NAPRTase and PYC in E. coli NZN111/pTrc99a-pncB-pyc reached the highest, which were 20.75 and 1.04 U/mg, respectively. At the same time, the total amount of NADH, NAD＋, and NAD （ H ） reached the highest. The fermentation results in the sealed bottles showed that 17.5 g/L glucose was consumed and 14.08 g/L was produced at 48 h and the accumulation of pyruvic acid was decreased to 0.11 g/L. The study provided a basis for the production of succinic acid in the engineered E.coli under anaerobic conditions.