Construction and application of temperature sensitive thermotolerant system in Escherichia coli

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.