L-亮氨酸高产菌TGL8207的定向选育及其发酵过程研究

Study on Rational Breeding and Fermentation Process of L-Leucine-Overproducing Strain TGL 8207

以谷氨酸棒杆菌TG95为出发菌株,通过原生质体紫外诱变、原生质体融合和硫酸二乙酯诱变,定向选育L-亮氨酸产生菌TGL8207。该菌株在未优化条件下摇瓶发酵72 h,产L-亮氨酸27.2 g/L,并且菌株的遗传标记和产酸能力十分稳定。研究了温度、pH和溶氧对菌株TGL8207积累L-亮氨酸的影响。采用10 L罐补料分批发酵64 h,L-亮氨酸产量达44.5 g/L,糖酸转化率达22.8%。

The L-leueine-overprodueing strain TGL8207 was constructed by methods of protoplast ultraviolet mutagenesis, protoplast fusion and diethyl sulfate mutagenesis with Corynebacterium glutamicum TG95 as the parent strain. This strain could produce 27.2 g/L L-leucine after 72 h in shake flask under an unoptimized condition, and the genetic characteristic and acid-productivity of TGL8207 were very stable. In addition, the effects of fermentation conditions （temperature, pH and dissolved oxygen） on L-leucine production were studied. A final L-leueine concentration of 44.5 g/L was obtained after 64 h in 10 liter fermentor with the sugar-acid conversion rate of 22.8%.