以L-缬氨酸生产菌谷氨酸棒杆菌XV0505为供试菌株,研究有机氮源对L-缬氨酸发酵的影响,确定了玉米浆代替豆饼水解液作为有机氮源的发酵工艺,降低了发酵成本;考察不同玉米浆浓度对谷氨酸棒杆菌XV0505发酵生产L-缬氨酸过程中生物量、耗糖速率、L-缬氨酸产量、副产物积累及氨消耗等方面影响,确定了玉米浆的适宜添加浓度;考察了玉米浆与生物素不同配比对L-缬氨酸分批发酵过程的影响,确定了最适生物素添加浓度。与原工艺相比,新工艺的菌体生物量及产酸提高了13.2%和18.5%。

The effects of organic nitrogen sources on the fermentation of L-valine were studied with L-valine-producing strain Corynebacterium glutamicum XV0505.Corn steep liquor was selected as the appropriate nitrogen source instead of soybean hydrolysates to reduce the cost of fermentation.The effects of initial concentration of corn steep liquor in fermentation process on biomass,glucose consumption rate,yield of L-valine,accumulation of byproduct and ammonia consumption rate were studied by carrying out fed-batch fermentation.The optimal initial concentration of corn steep liquor was also determined.The effects of the combined agents,biotin and corn steep liquor,on overproduction of L-valine were also studied,and the concentration of biotin was optimized.Compared with those of the original process,the biomass and L-valine production from the improved process were increased by 13.2% and 18.5 % respectively.