Optimization of the fermentation of rhG - CSF using recombined strain

WANG Juan; LI Xi-ping

Abstract：Objective To improve the rhG - CSF protein from the recombined strain Escherichia coli BL21( DE3) Plys,the batch fermentation conditions was optimesed. Methods We determined the influence of the parameters at some crucial control points,including different inoculation amount(1% ~ 10% ),the OD600nm of fermentation culture when adding inducer IPTG and the different concentrations of dissolved oxygen(DO)(20% ~ 80% )on the final protein expression in 100 L batch level fermentation. A SDS - PAGE was used to analyze the protein expression. Results The optimized fermen-tation condition was as follow:inoculum quantity 5% ,IPTG should be added when the OD600nm of culture reaches 10 ~ 15,at the beginning of inducing the expression of object protein,the DO concentration was controlled under 80% ;After inducing 20 min,the pH of medium was kept at around 7. 0 by adding ammonia,the DO concentration was kept at 20% ~ 40% ;The bacteria was collected after inducing 5 hours. The production of rhG - CSF was higher after optimizing the fermentation con-ditions. Conclusion The optimized fermentation conditions for rhG - CSF production in E. coli BL21(DE3)Plys provided import direction for its large scale preparation.