大肠杆菌丝氨酸转运系统单基因敲除对丝氨酸生产的影响

氨基酸转运系统改造是一种重要的氨基酸菌种选育方式。sda C,cyc A,sst T和tdc C是目前报道的大肠杆菌中与L-丝氨酸转运吸收相关的四个基因,本研究以实验室前期构建的L-丝氨酸工程菌SWCH-05为基础,采用Red重组系统,分别构建了sda C,cyc A,sst T和tdc C单基因敲除菌,并通过补料分批发酵实验考察了转运吸收基因缺失对菌株产L-丝氨酸的影响。发酵结果表明,sda C敲除菌L-丝氨酸产量达到了16.3 g/L,与出发菌株相比提高了43%,cyc A敲除菌L-丝氨酸产量为14.1 g/L,与出发菌株相比提高了25%,而sst T和tdc C基因敲除菌的L-丝氨酸产量均与对照菌相近。 

Effect of single- gene knockout of L- serine transport system on L- serine production in Escherichia coli

Transport system modification is an important method in strain improvement.It has been reported that the uptake of L- serine was regulated by four genes of sda C,cyc A,sst T and tdc C in Escherichia coli.In this study,the four single- gene knockout mutant strains of sda C,cyc A,sst T and tdc C were constructed,respectively. The fermentation results showed that the sda C and cyc A knockout mutants produced 16.3 g / L and 14.1 g / L L- serine,respectively,which were 43% and 25% higher than that of the control strain. However,the production of sst T and tdc C mutants were both similar to the control strain.