CULTURE CONDITIONS FOR YIELD IMPROVEMENT USING A THREONINE-PRODUCING ESCHERICHIA COLI STRAIN
Production of threonine in industry is mainly carried out by fermentation using the overexpressing bacterial strains. In this report we used a threonine producing Escherichia coli strain M122 bearing the rhtE overexpression. The practical production of threonine was examined using this straia This investigation was used in establishing optimal culture conditions for achieving the better threonine production. The pH and dissolved oxygen concentration were chosen to test whether or not influenced the yield of threonine. Firstly, we examined the possibility that pH influences the threonine-induced lethality. Data showed that the threonine production was pH dependent and the yield and cell growth in pH 7. 0 were higher than that at other pH values. We then observed the effects of dissolved oxygen concentration on the cell growth and the threonine productioa It was found that the optimal oxygen concentration in the delayed phase was 20％, logarithmic phase 50％, and stable phase 20％.
threonine E. coli strain pH value oxygen concentration
Kong Jing Chen Jun Wu jie
Huaiyin Institute of Technology, Huaian 223003, China
国际会议
重庆
英文
428-430
2011-10-28（万方平台首次上网日期，不代表论文的发表时间）