L-Gln高产突变株发酵中试过程的研究

Study on the pilot-scale fermentation process of a mutant with higher L-glutamine production

以诱变筛选得到的高产Gln突变株C.glutamicum N-U-6为研究对象,对其进行了5L发酵罐的中试实验。在采用搅拌速率为850r/min和通气量为1.5vvm的条件下,在发酵中后期流加30%的尿素达到控制pH维持6.2和补充氮源的双重目的,进一步提高了产量,最高达56.67g/L,发酵周期缩短到44h。此外还进行了氮饥饿处理的实验:初期脲量减少为原来的60%,后期补加尿素以补充氮源同时也起到控制pH的作用,谷氨酰胺的产量达到62.52g/L,比氮饥饿处理前(56.67g/L)提高了约6%,其发酵周期缩短到40h。

A mutant（C.glutamicum N-U-6）with higher L-glutamine production had been obtaind,then the process of glutamine production of the mutant in the 5L fermentor was investigated.To control pH in the late age of fermentation played an important role in the process.When pH of culture medium was controlled at about 6.2 by feeding 30% urea after it naturally dropped to this pH,more glutamine（56.67g/L）was obtained and the fermentation time was reduced from 48h in the Erlenmeyer flask to 44h.Furthermore,the effect of nitrogen starvation on glutamine synthesis was researched by reducing the quantity of initial urea by 40%.More glutamine（62.56g/L）was produced.Also,the fermentation time was reduced to 40h.