等离子诱变选育木糖醇高产菌及发酵条件优化

Mutation Breeding of High-yield Xylitol Strain by Plasma and Optimization of Fermentation Conditions

以热带假丝酵母Y-14(Tropical candida)为出发菌株,采用等离子体对其进行诱变,得到最佳诱变条件:在功率120 W下处理150s,致死率达到96%。诱变后经过筛选得到1株高产木糖醇的菌株Y-117,与出发菌株相比,其木糖醇产量提高了30.4%。在单因素试验的基础上,通过响应面分析试验对菌株Y-117的发酵条件进行优化,得到最佳条件:初始木糖添加量105g/L、温度30.5℃、摇床转速190r/min。在此条件下,Y-117的木糖醇产量为76.45g/L,比出发菌株高42%。

The Tropical candida Y-14 is mutagenized by atmospheric and room temperature plasma （ARTP）. The optimal mutation condition is 150 s at 120 W, under such condition, the lethality rate is 96%. The strain Y-117 with high-yield xylitol is screened from mutagenized Tropical candida. The xylitol productivity of Y-117 is increased by 30. 4% comparing with Tropical candida Y-14. The single factor experiment is utilized combining with response surface methodology to optimize the fermentation conditions for strain Y-117. The fermentation conditions of Y-117 are optimized as follows, initial xylose content is 105 g/L, temperature is 30.5 ℃, and shaker speed is 190 r/min. Under these conditions, the xylitol productivity of Y-117 is 76.45 g/L, which is 42% higher than the starting strain.