谷氨酸高产菌GDK-9的定向选育及其发酵过程研究

以天津短杆菌GDK6为出发菌株,通过原生质体紫外诱变、紫外诱变和硫酸二乙酯(DES)诱变定向选育L-谷氨酸生产菌。经摇管初筛、摇瓶复筛、遗传标记验证、单菌落分离和连续传代,最终筛选出1株L-谷氨酸高产菌GDK-9。该菌株在未优化条件下摇瓶发酵42h产L-谷氨酸79.2g/L。另外,试验结果证实GDK-9菌株的遗传标记和产酸能力十分稳定。在优化条件下,通过7L罐发酵32h,谷氨酸产量达131.5g/L,糖酸转化率达到62.2%。

Rational Breeding of Glutamic Acid-overproducing Strain and Study of Fermentation Process

Brevibacterium tianjinese GDK6 as the parent strain was rationally engineered to produce L- glutamic acid by methods of protoplast ultraviolet,ultraviolet and diethyl sulfate mutagenesis.The glutamic acid-overproducing strain GDK-9 was screened through shake-tube primary screening,baffle flask second screening,genetic marker test,single clone isolation and continuous passage.This strain could produce 72. 9g/L L-glutamic acid after 42h in baffle flask under an un-optimized condition.In addition,results showed that the genetic characteristics and productivity of GDK-9 were very stable.Under the optimized fermenta- tion conditions,a final L-glutamic acid concentration of 131.5g/L was obtained after 32h in 7 liter fermentor with the conversion rate of 62.2%.