Effect of cultivation conditions on neutral protease produced from Aspergillus oryzae ZW-06 in solid-state fermentation

Orthogonal design was applied to optimize fermentation conditions producing neutral protease from Aspergillus oryzae ZW-06.The seven factors including medium composition and cultivation conditions were chosen in the orthogonal design.The optimum composition in the culture medium was as follows: 8 g of wheat bran and 2 g of soybean with adition of 0.5% Na2CO3.The optimum temperature and moisture for producing neutral protease from the medium was 30.0℃ and 60%(W/W),respectively.About 26.7 g/L of the culture medium and 20%(V/W) of inoculation volume were suitable for production of enzyme.48 h of cultivation was enough for producing maximum neutral protease.Under optimum culture conditions,the activity of neutral protease from A.oryzae ZW-06 was 23 738 U/g.