Study on the Optimum Fermentation Condition of Aspergillus niger Solid-state to Produce Acid Protease

The medium composition and fermentation conditions were optimized for solid-state fermentation of Aspergillus niger.The experimental results showed that the optimum medium and conditions were as follows: rice bran 20g,6 g/kg corn meal,ammonium nitrate nitrogen 5 g/kg,MnCl2 4 g/kg,liquid ratio 1.0∶1.5,adjusted initial pH7,6 mL/100g of the volume of vaccine inoculation,40℃、180 r / min fermentation time 72 h,in shake flask enzyme production rate reached 1120.0 U/mL,2.9 times more than that under base medium.