发酵豆粕分泌蛋白酶的兼性厌氧型菌株筛选与鉴定

在厌氧条件下筛选固态发酵豆粕的生产菌株。以透明圈法分别对中外发酵豆粕、霉豆腐、酱油发酵原液等进行厌氧条件下高产大豆蛋白酶生产菌株进行筛选。利用初筛得到的单菌在厌氧条件下发酵豆粕，以小肽含量和蛋白酶酶活力为指标进行复筛，得到优势菌株NCU646。结果表明：厌氧条件下NCU646菌株在豆粕固态发酵培养基中产蛋白酶活力高达9600U/g，发酵后豆粕中小肽含量提高10倍以上，豆粕中粗蛋白含量增加了近10.0%。经过生理生化鉴定和16S rRNA基因序列分析鉴定，该菌株为兼性厌氧型的枯草芽孢杆菌(Bacillus subtilis)。

Screening and Identification of Facultative Anaerobic Bacteria Capable of Utilizing Soybean Meal to Produce Proteases

In order to screen an excellent strain which can utilize soybean meal to produce proteases under anaerobic conditions, 10 pure strains conserved in our laboratory were compared for their abilities to produce proteases and degrade crude proteins in solid-state fermenting soybean meal as well as colonial features. NCU646 was found to be the best strain. The protease activity at the end of solid-state fermentation of soybean meal by this strain reached up to 9600 U/g, and fermented soybean meal showed over 10-fold increase in the content of small peptides and nearly 10.0% increase in crude protein content in comparison with unfermented soybean meal. Physiological and biochemical identification and 16S rRNA sequence analysis revealed that NCU646 was a Bacillus subtilis strain.