从多年被废弃畜禽血液浸染的土壤中,分离筛选出16株菌株。根据在酪蛋白/明胶平板上蛋白质水解圈比值大小,初步确定8株菌株为被选菌株;并分别在Hb发酵培养液中发酵72h,测定蛋白酶活力、游离氨基酸含量、可溶性蛋白质含量、Hb降解率,最终确定一株菌株(编号为Lact5.Ⅲ)为所有被筛选出来的16株菌株中的最佳菌株。经过菌落形态观察初步确定为细菌,进一步测定生理、生化反应指标,鉴定该菌株为蜡状芽孢杆菌(Bacillus Cereus)。
Sixteen strains were isolated from soil polluted by discarded poultry and livestock for many years. According to the size of ratio of hydrolysis ring of casein/gelatin on plate, eight bacterial strains were initially selected as candidates. Then they culture in the Hb medium for 72 h, to test their protease activity, content of free amino acids, content of soluble protein, degradability of Hb, finally one strain (No. LatS. Ⅲ was screened as the best among the 16 strains, it belongs to Bacillus cereus after characterization with its morphology and further study on its physiology and biochemistry.