Optimization of multienzyme production by two mixed strains in solid-state fermentation.

F(3) and F(4) strains of Aspergillus niger were screened from five strains of fungi to produce multienzyme preparations (containing cellulase, hemicellulase, glucoamylase, pectinase, and acidic proteinase) as dietary supplementation. Enzyme activities indicated that 1:4 (F(3) to F(4)) was the optimum mixture proportion, and 0.3% (W/W) was the preferable pitching rate. In bran mash containing 54.5% (W/W) water, F(3) and F(4) could produce the supplementation better when cultured 30 to 36 h at 30 degrees C. Monofactorial and orthogonal experiments were performed to optimize media. Results of the variance and range analysis showed that the optimum medium contained 80 g of bran, 20 g of cottonseed powder, 1 g of (NH(4))(2)SO(4), and 0.1 g of KH(2)PO(4). When F(3) and F(4 )strains were cultured in the optimum medium containing 54.5% (W/W) water, the activity of cellulase, hemicellulase, glucoamylase, pectinase, and acidic proteinase reached 996; 15,863; 13,378; 7,621; and 5,583 U/g, respectively.