Solid fermentation of Aspergillus niger SL2-111 producing multi-enzymes

The solid fermentation condition of Aspergillus niger SL2-111 was studied by using single-factor research and orthogonal test based on the response value of acid protease. The results showed that the optimal medium contained 8.25 g fresh bran, 4.5 g rice bran, 1.5 g cake bean, 0.3 g (NH4)2SO4, 0.06 g K2HPO4, 0.075 g CaCl2, 8.6 mL water. The initial pH was at 5.5, and culture temperature was fermented at 28℃ for 30 h and then at 23℃ for later 30 h. The enzyme activities of acid protease, pectinase and cellulase were 12586 U/g, 16490 U/g and 9822 U/g, respectively, when the strain was grown on the optimal medium under the above culture conditions in 250 mL Erlenmeyer flask.