产角蛋白酶菌株的筛选及发酵条件优化

Screening of production keratinase strains and optimization of fermentation conditions

采用以羽毛为唯一碳氮源的无机盐培养基,通过考察HC值(水解圈直径与菌落直径的比值)、羽毛的降解程度,筛选得到10株产角蛋白酶的菌株,经测定10株菌株摇瓶发酵液的蛋白酶活力,确定了一株产酶能力较强的菌株CJPE209,并对菌株进行鉴定,菌株CJPE209被鉴定为芽孢杆菌(Bacillus sp.),其发酵液酶活为267 U/mL。通过单因素实验,确定了菌株CJPE209产角蛋白酶的最适发酵条件:发酵周期48 h,培养基装液量25 mL/250 mL,发酵温度37℃,初始pH7,摇床转速220 r/min,发酵液酶活为337.6 U/mL,是优化前的1.26倍。

In this research, a medium in which feather was the sole nitrogen source was used for screening microorganisms which product keratinase.By examining HC value（ the ratio of hydrolysis spot diameter to colony diameter） and degradation rate of feather,10 strains were got. By comparing the enzyme activity of the fermentation culture of the 10 strains, a strain named CJPE209 which highly product keratinase was selected for next research. CJPE209 was identified as Bacillus sp..Through the method of sigle- factor experiments, the optimal fermentation condition of CJPE209 was determined as follows- fermentation time 48 h, loading volume 25 mL/250 mL, fermentation temperature 37 ℃, initial pHT, rotation rate 220 r/min. After optimization, the enzyme activity of fermentatinn culture reached 337.6 U/mL which was 1.26 folds as high as that before optimization.