胞外纤溶酶产生菌的筛选及其产酶条件研究

从豆豉、酱豆和纳豆样品中分离筛选到一株具强力纤溶活性的细菌 ,编号为NK—5,经鉴定为芽孢杆菌属枯草杆菌群细菌。该菌在固态基质及液体培养基中均产生大量胞外纤溶酶。摇瓶发酵试验表明 ,其最适产酶碳源和氮源分别为蔗糖和蛋白胨。通过正交试验确定最适产酶培养基为 :豆粕粉 2 0 %、麸皮 0 5%、玉米淀粉 0 5%、KH2 PO4 0 2 %、K2 HPO40 4 %、MgSO4 0 0 5%、CaCl2 0 0 2 % ,pH7 0。在优化条件下 ,发酵液酶活达 6 83 3IU/mL

Screening of Extracellar Fibrinolytic Strain NK-5 and Its Enzyme Production Conditions

A extracellar fibrinolytic strain NK 5 was screened from out from 15 strains with fibrinolytic activity which isolated from traditional fermented soybeans. The strain was identified as Bacillus substilis. On boiled soybeans the strain exhibited maximum fibrinolytic activity at 30℃ for 24 h. Studies on the condition of enzyme production revealed that its optimum carbon source and nitrogen source were sucrose and peptone respectively. The optimum medium for enzyme production was obtained according to orthogonal experiments and its formulates was defated soybean powder 2%, maize starch 0.5%, wheat bran 0.5%, MgSO 4 0.05%, KH 2PO 4 0.2%, K 2HPO 4 0.4%, CaCl 2 0.02%. Using this medium, enzyme production of NK 5 strain can reach 683.3?IU/mL.