中高温大曲中高产蛋白酶菌株的选育

The Breeding of High Protease-producing Strain Isolated from Songhe Daqu

从宋河大曲中共分离得到39株产蛋白酶芽孢菌株,采用透明圈法和摇瓶发酵法筛选出1株高产蛋白酶菌株MSPN-11,酶活达114.8U/m L。以该菌株为出发菌种,采用紫外诱变的育种方法,以致死率和蛋白酶活力为指标选育高产蛋白酶菌株。研究表明:紫外照射时间160s、照射距离50cm^55cm的剂量处理,菌株致死率达80%以上,且90%诱变菌株的R/r值在3.0以上,得到1株高产蛋白酶菌株MSPR8,酶活提高了26.38%。

39 protease-producing bacillus isolated from Songhe Daqu were obtained. The strain MSPN-11 which demonstrated high protease productivity（114.8U/m L） was screened by observing transparent rings and measuring the protease activity of shake flask fermentation. The high protease-producing strain would be breeded using ultraviolet mutagenesis with protease activity and lethality rate of colonies as measuring indexes.The results showed that： lethality rate of colonies reached above 80% when UV irradiation time and distance was chose 160 s and 50cm-55 cm, respectively. 90% of the mutant strain R/r values were above 3.0. Strain MSPR8 which showed higher protease activity increasing 26.38% was obtained by screening strains breeded using ultraviolet mutagenesis.