维生素B12分批与补料分批发酵的研究

首先对维生素B12产生菌Propionibacterium shermanii在7L发酵罐内分批发酵下的菌体生长及产维生素B12的特性进行了研究。分批发酵的结果表明，虽然提高葡萄糖的浓度可以提高产量，但是存在着菌体生长受抑制，耗糖缓慢，发酵周期长的缺陷。继而进行了间歇补料分批发酵工艺的研究，确定了初糖浓度及补糖策略。发酵最终菌体干重达16．96g／L，较分批发酵提高50％；维生素B12的产量达38．55mg／L，较分批发酵提高16％；有效缩短了发酵周期，较分批发酵缩短24h。

Study on Batch and Fed-Batch Fermentation of Vitamin B12

Fed-batch fermentations of vitamin B12 by Propionibacterium skermanii were conducted in a 7L fermentor to investigate characteristics of the cell growth and vitamin B12 production. The experimental results of batch fermentation showed that high concentration of glucose inhibited cell growth, and led to slow sugar consumption and long fermentation time. Then fed-batch feimentations were undertaken in a 7L fermentor to solve the problem. The effects of the initial glucose concentration and the maintaining level were studied to determine the optimum condition. The optimized fed-batch fermentation resulted in 16.96 g/L dry cell weight and 38. 55 mg/L vitamin B12 production, which were 50% and 16% enhancement compared to batch fermentation. Furthermore, the result showed a reduction of the fermentation time up to 24 hours.