产丙酮酸氧化酶重组大肠杆菌的发酵过程质粒稳定性研究

摘要

研究了碳源、温度、溶氧、pH值及外源丙酮酸氧化酶表达对重组大肠杆菌DH5α/pSML?PyOD质粒稳定性的影响. 结果表明,以甘油为碳源,37 ℃,装液量10%~15%条件下重组菌质粒稳定性最好. 当发酵过程中体系pH值在6~7之间时,质粒稳定性较高,但当pH提高至7.5时,质粒稳定性会有所下降,重组菌在低pH值条件下有利于产丙酮酸氧化酶. 外源蛋白表达使得重组菌质粒稳定性有所下降.%The influences of carbon resource, temperature, DO, pH and heterologous pyruvate oxidase expression on the plasmid stability of the recombinant E.coli DH5α/pSMLPyOD were investigated. The results show that glycerol, 37℃ and the ratio of 10-15% medium to volume of the flask (v) were the optimum conditions for the plasmid stability during the process of recombinant E.coli DH5α/pSMLPyOD cultivation, that the recombinant could retain high plasmid stability in pH6-7 and that heterologous PyOD expression decreased the plasmid sta?bility apparently.