L-缬氨酸产生菌的选育及其发酵培养基的优化

以黄色短杆菌(Brevibacterium flavum)NJ-237为出发菌株,通过梯度传代适应性培养及同浓度药物平板富集培养的方式,逐步提高菌体的抗药物性能,获得了1株耐高糖和耐高浓度α-氨基丁酸(-αAB)的菌株NJ-2372。在单因素实验的基础上,利用响应面分析法对影响该菌株L-缬氨酸(L-Val)产量的3个重要因素玉米浆、生物素(VH)、硫胺素(VB1)的添加量进行优化。结果表明:当玉米浆、VH、VB1最佳添加量分别为11 g/L、35μg/L和101μg/L时,摇瓶发酵72 h,L-Val摇瓶发酵产量达到52.9 g/L。

Breeding of L-valine producer and optimization of its fermentation medium

Using Brevibacterium flavum NJ-237 as the original strain by gradual adaptive culture and synchronized enrichment culture on the same concentration of additives,a L-valine producing mutant NJ-2372 was obtained.It was resistant to high concentration of glucose and α-aminobutyric acid.On the basis of single-factor experiments,the optimal concentrations of the three important factors including corn steep liquor,VH,VB1 were obtained by response surface methodology.The concentrations of corn steep liquor,VH,VB1 were 11 g/L,35 μg/L,and 101 μg/L,respectively,and L-valine production of the strain was 52.9 g/L for 72 h in shaker flask.