[Objective] The aim was to select strains producing alkaline protease from soil and study the conditions for enzyme production. [Method] Eight strains producing alkaline protease were isolated from soil through plate isolation, and their ability of enzyme production was measured by filter paper and Folin-phenol method. The strain with strongest ability of enzyme production was selected as study object, then the factors influencing the ability of enzyme production was studied, finally the conditions for enzyme production was optimized through orthogonal test. [Result] No.5 strain was selected as study object due to its strong ability of enzyme production (6. 00 U/ml) , which accounted for 134.1% of that of Bacillus licheniformis, and it was gram-positive Clostridium spores. Orthogonal test showed that the optimal condition for producing protease was an environment with pH = 11, 0.3% of sucrose and 0. 8% of peptone in the fermentation medium, puls inoculation a-mount of 105 cfu/ml. In addition, peptone had significant impact on the level of enzyme production. [Conclusion] The study could provide theoretical references for the selection of strains producing alkaline protease.%[目的]从土壤中筛选产碱性蛋白酶菌株,并优化产酶条件.[方法]采用平板分离方法从土壤样品中分离出8株产碱性蛋白酶菌株,采用滤纸片法和Folin-酚法测定8个菌株的产酶能力.将具有较强产酶能力的菌株作为目的菌株,研究该菌株产酶能力的影响因素,并采用正交试验法优化产酶条件.[结果]经过初筛和复筛,从土壤中得到一个碱性蛋白酶高产菌株(5号),作为目的菌株,其产酶能力为6.00 U/ml,为地衣芽孢杆菌的134.1％,该菌株为革兰氏阳性芽孢梭菌.正交试验表明,在pH为11的初始发酵培养基中添加0.3％蔗糖和0.8％蛋白胨,并以105个/ml的接种量接种,目的菌株可得到较好的产酶效果,且蛋白胨对该菌株产酶能力具有显著影响.[结论]该研究为产碱性蛋白酶菌株的筛选提供了理论参考.
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