大肠杆菌温敏耐热系统的构建与应用

Construction and application of temperature sensitive thermotolerant system in Escherichia coli

发酵过程中热胁迫不仅影响微生物的生长和生产,还因冷却控温增加了生产成本。通过人工设计合成的温敏型RNA开关调控来源于腾冲嗜热菌(Thermoanaerobacter tengcongensis MB4)的热激蛋白Dna K的表达,该温敏型耐热系统显著提高了大肠杆菌的耐热性,同时还减少了大肠杆菌在37℃过表达热激蛋白的代谢负荷。将该系统应用于产赖氨酸大肠杆菌的高温发酵,不仅强化了其在40℃下的生长能力,而且显著提高了其在高温下的生产能力,赖氨酸产量比对照组提高了2.95倍。温敏型耐热系统的应用为人工耐热生物系统的构建提供了新方法。

The heat stress produced in fermentation process can not only affect the growth and reproduction of microorganisms, but also increases production cost from cooling and temperature control. The improvement of strain thermotolerance is highly desire for fermentation industry, which could significantly go up productivity and reduce production cost. So in this study, an artificial design and synthesis RNA switch with temperature sensitivity is employed to regulate and control the heat shock protein Dnak from Thermoanaerobacter tengcongensis MB4, which leads to the thermotolerance improvement of Escherichia coli. This improvement not only alleviated the burden of overexpressing heat shock protein in Escherichia coli at 37℃, but also enhanced its productivity at high temperature. The results of application test show that at 40℃ the output of lysine produced by E. coli increases by 2.95 folds, when compared with control group. This success could be twilight for the development of new method to prepare thermotalerance microorganisms.