豆豉中蛋白酶高产菌筛选及产酶条件的研究

Screening of High-Yielding Protease Bacteria in Fermented Black Beans and Study on its Enzyme Production Conditions

为了提高微生物蛋白酶的发酵水平,从豆豉中筛选蛋白酶高产菌株并研究其产酶条件。采用平板透明圈法和摇瓶发酵法进行筛选,获得一株蛋白酶高产菌株DC17。通过菌体形态观察、生理生化特征分析和16S rDNA鉴定,菌种DC17被鉴定为解淀粉芽孢杆菌。利用小型发酵罐对菌株DC17进行蛋白酶发酵研究,确定了最佳的碳源、氮源、温度、pH及时间分别是可溶解性淀粉、牛肉膏、30℃、7.0和36 h。在最佳条件下,发酵液中的蛋白酶活力可达950 U/mL。

In order to improve the production level of microbial proteases during fermentation,strains of high protease activity were screened from Douchi.A high-yielding protease strain DC17 was isolated by methods of plate transparent circle and shake flask fermentations.DC17 was identified as Bacillus amylolyticus by morphological observation,physiological and biochemical characteristics analysis and 16S rDNA identification.The optimal carbon source,nitrogen source,temperature,pH and fermentation time were determined to be soluble starch,beef extract,30℃,7.0 and 36 h,respectively.Under the optimal conditions,the activity of protease in fermentation broth reached 950 U/mL.