转运基因对大肠杆菌利用木糖产L-乳酸的影响

The Effect of Transfer Gene on the Production of L Lactic Acid by E.Coli Xylose

为加强大肠杆菌(Escherichia coli)WL210利用混合糖产L-乳酸的能力,通过RED同源重组技术敲除了甲基半乳糖苷转运系统基因mglB、半乳糖转运系统基因galP,构建双缺陷乳酸工程菌WL230。结果表明:与出发菌株WL210相比,以6%混合糖(3%葡萄糖和3%木糖)为碳源,mglB/galP双基因缺陷菌株WL230同时可利用葡萄糖和木糖,其木糖利用速率和乳酸生产强度分别提高了298.92%、42.63%,且转化率高达90.21%。

In order to enhance the ability of Escherichia coli WL210 to use mixed sugars to produce L lactic acid,the methylgalactoside transport system gene mglB and the galactose transport system gene galP were knocked out through the RED homologous recombination technology,and a new strain WL230 was constructed.The results showed that with 6%mixed sugar(3%glucose and 3%xylose)as the carbon source,the mglB/galP double gene deficient strain WL230 can simultaneously utilize glucose and xylose.Compared with the starting strain WL210,its xylose utilization rate and lactic acid production intensity were increased by 298.92%and 42.63%respectively,and the conversion rate was as high as 90.21%.