重组大肠杆菌HT02高密度高表达HT-1融合蛋白发酵过程优化

Optimization of high cell culture of recombinant E.coli HT02 for high expression of HT-1 fusion protein

发酵工艺放大是将实验室成果产业化的必要一环,随着发酵规模的扩大,工艺流程也会有相应的调整,导致微生物所处的生长环境以及生长代谢状态的改变,从而影响大体积发酵罐的发酵水平。本文以一株产HT-1融合蛋白的重组大肠杆菌HT02为研究对象,在200L发酵罐中研究了分批补料培养时菌体生长与HT-1融合蛋白表达的特性,通过采用提前诱导、增加接种量的手段,解决了因增加二级种子培养工艺而导致的200L发酵罐中HT-1融合蛋白表达水平下降的问题,最终使菌体密度、HT-1融合蛋白表达水平、融合蛋白细胞得率以及融合蛋白体积得率分别达到55.1g·L-1、27.4%、0.056g·(gcell)-1和3.103g·L-1,较工艺改进前发酵水平分别提高了9.8%、23.4%、14.3%和25.2%,实现了在200L发酵罐中高密度高表达发酵,为HT-1工业化生产提供了指导。

The scale-up of fermentation process plays an important role in the industrialization of lab results. As the increase of fermentation scale, the microenvironment of microorganism would be different, which would result in the change of microorganism metabolism and affect the results of scale-up. In order to accomplish the industrialization of HT-1 production, high-expression of HT-1 fusion protein was carried out with fed-batch culture method of E. coli in a 200 L fermentor. The problem of the decrease in HT-1 fusion protein expression level caused by secondary seed culture process was solved by the methods of advancing initial induction and increasing inoculation volume. As a result, the cell density, the expression level, the cell yield as well as the volume yield of HT-1 fusion protein were achieved to 55.1 g · L^-1,27.4%, 0.056 g · （g cell）^-1 and 3.103 g · L^-1, respectively. Compared with the results beforeoptimization, these indexes were increased by 9.8%, 23.4%, 14.3% and 25.2%, respectively. These results provide an important reference for the optimization and scale-up of HT-1 production.