Screening of production keratinase strains and optimization of fermentation conditions

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 pH7, rotation rate 220 r/min. After optimization, the enzyme activity of fermentation culture reached 337.6 U/mL which was 1.26 folds as high as that before optimization.