混菌发酵生产γ-聚谷氨酸的工艺条件优化

Optimization of culture conditions for producing poly(γ-glutamic acid) by mixed fermentation

采用谷氨酸棒杆菌S9114和枯草芽胞杆菌NTG-4在10 L自控发酵罐上进行混菌发酵,探索混菌发酵生产γ-聚谷氨酸的可行性并进行工艺优化。结果表明:温度、接种量、pH及溶氧对聚谷氨酸发酵有较大影响,发酵前期维持32℃,6 h提温至37℃变温控制,谷氨酸棒杆菌和枯草芽胞杆菌接种量分别为5%和0.5%,pH 7.0,溶氧20%最有利于γ-聚谷氨酸发酵,在此条件下发酵32 hγ-聚谷氨酸最高产量为38.3 g/L。

The effects of mixed fermentation conditions on production of poly （ y-glutamic acid） （T-PGA） were investigated in a 10 L fermentor. The result showed that the temperature was an important factor for the T-PGA production. With the temperature adjusting from 32 ℃ to 37 ℃ at 6 h in the process of culti- vation, the T-PGA production was enhanced. Furthermore, the experiments of optimizing inoculation vol- ume of Corynebacterium glutamicum and Bacillus subtilis, pH and dissolved oxygen were performed to in- crease the T-PGA production. The higher T-PGA production was obtained when the inoculation volume of C. glutamicum and B. subtilis, pH and dissolved oxygen were adjusted to 5% , 0.5% , 7.0, and 20%, respectively. Under the optimal culture conditions, a final T-PGA concentration of 38.3 g/L was ob tained after 32 h fermentation.