一株产碱性蛋白酶芽孢杆菌的筛选、鉴定及应用初探

为了筛选碱性蛋白酶产生菌并探讨其对蛋白质饲料的发酵效果,以肉粉厂表层土壤为菌株分离源,利用脱脂牛奶培养基分离和纯化蛋白酶产生菌,通过形态特征、生理生化和16S rRNA基因序列分析确定菌株的分类地位,并采用L9(33)正交设计研究筛选出的优势菌种的接种量(3％、6％和12％)、种子液培养时间(12 h、24h和48 h...

Screening, Identification and Application of a New Bacillus Producing Alkaline Protease

To screen a bacterium producing alkaline protease and study its fermenting effect on protein feeds,a new strain was isolated from topsoil surface of meat power plant and purified using skim milk media;its taxonomy was established according to its morphological features,physiological and biochemical characteristics as well as phylogenetic analysis of 16S rRNA gene sequences;effects of inoculation,culture time of seed liquid and solid-state fermentation time on fermented performance of soybean meal and blood powder were investigated by orthogonal experiments.Results showed that this strain was the most closely related to Bacillus subtilis and named Bacillus subtilis strain D-2;under optional fermentation conditions,the contents of small peptides were significantly increased to 17.06%and 12.73%in fermented soybean meal and blood powder,respectively;these optional fermenting conditions as follows;the inculum of 6%,seed liquid culturing time of 24 h,and solid-state fermentation time of 48 h.These results indicated that alkaline protease produced by Bacillus subtilis strain D-2 effectively decomposed protein in both soybean meal and blood powder,which improved dietary performance of protein feeds.