强化工业大肠杆菌生长特性的研究

大肠杆菌是制药工业中的重要蛋白质药物生产菌株。然而乙酸积累、中心碳代谢负担过重等不良因素严重制约着大肠杆菌的高密度生长。利用Red同源重组技术,构建icd和ptsG双基因敲除大肠杆菌菌株,以分流碳代谢流,提高碳利用效率,最终增加菌体生物量。同时构建ppc过表达质粒,减少乙酸积累。发酵结果显示,构建的重组菌株产酸量大幅减少,pH值平均升高20%,菌体浓度增加了50%,生长特性得到了强化。

Improvement of Growth Characteristics of Escherichia coli

Escherichia coli is an important strain in the protein pharmaceutical industry. However, because of acid accumulation and central carbon metabolism burden severely restrict high-density Fermentation of E. coli. Using Red homologous recombination technology, we build icd and ptsG double-gene knockout strains of E. coli in order to divert metabolic flux of carbon to improve the carbon efficiency and ultimately increase the bacterial biomass. At the same time, we construct a ppc over-expression plasmid to reduce the acid accumulation further more. Fermentation results showed that the recombinant strains significantly reduced the amount of acid, pH increased of 20% in average cell ,and the bacterial biomass increased by 50%. These results demonstrate that the growth characteristics have been enhanced.