米曲霉GN-2菌株产中性蛋白酶固体发酵条件的优化

摘要

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 ×106 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.%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1016.9 U/g。