米曲霉固态发酵麻疯树籽饼产中性蛋白酶条件的研究

Optimization of solid state fermentation of Jatropha curcas L.seed cake with Aspergillus oryzae to produce neutral protease

以实验室筛选出的米曲霉(Aspergillus oryzae)Asp-1为菌种,麻疯树籽饼为发酵主料,采用固态发酵法生产中性蛋白酶。考察了固态发酵培养基液固比、初始pH、接种量等发酵条件,以及麻疯树籽饼中添加麸皮、碳源、氮源对该菌株产酶能力的影响。经单因素和正交实验获得最佳发酵条件为:培养基液固比1∶1,初始pH6,接种量每10g培养基含有1×108个孢子,培养基中麸皮添加量10%、葡萄糖添加量0.5%、蛋白胨添加量1%。最佳条件下发酵2d酶活可达3759.8U/g。

The Jatropha curcas L. seed cake was used as a substrate to produce neutral protease by solid state fermentation with Aspergillus oryzae （ Asp - 1 ） screened from our laboratory. The effects on the activity of protease of fermentation conditions （ water content of culture medium, initial pH, amount of inoculation） and the addition of wheat bran, carbon source and nitrogen source in the cake were studied. The results showed that the optimal conditions were as follows：water content of medium 50% ,initial pH 6, amount of inoculation 1 ×10^7 spores per gram medium,dosage of wheat bran 10% ,dosage of glucose 0.5% ,dosage of peptone 1%. The activity of protease was 3 759.8 U/g by fermenting 2 d at the optimal conditions.