米曲霉GN-2菌株产中性蛋白酶固体发酵条件的优化

Optimizing the Solid Fermentation Conditions of Neutral Protease from Aspergillus oryzae GN-2 Strain

对米曲霉(Aspergillus oryaze)GN-2菌株产中性蛋白酶固体发酵的条件进行优化。单因素试验结果表明,米曲霉的固体适宜发酵条件为发酵原料麸皮∶豆粉为4∶1(质量比,下同),培养时间60 h,培养温度25℃,培养基加水量10 mL,接种量1×106个/mL孢子悬液2.0 mL,培养基起始pH 6.0,0.02%(NH4)2SO4溶液1 mL。正交试验结果表明,在温度25℃、加水量20 mL、麸皮∶黄豆粉为4∶1、培养时间72 h的条件下酶活力最高,达1 016.9 U/g。

The optimal solid fermentation conditions of neutral protease from Aspergillus oryzae GN-2 strain was studied. The results of single factor test showed that the highest neutral protease activity was obtained under the conditions of wheat bran and soybean powder addition ratio 4：1, fermentation time 60 h,temperature 30℃,water addition 10 mL, inoculum amount 2.0 mL 1 ×10^6 spores/mL spore suspension, the initial medium pH 6.0,0.02%（NH4﹚2SO4 1 mL. The results of orthogonal experiment showed that the highest neutral protease activity was obtained when the solid fermentation was carried out at 25℃for 72 h, water addition 20 mL and the addition ratio of wheat bran and soybean powder 4：1, with the highest neutral protease activity of 1 016.9 U/g.