Cellulase Production by Aspergillus japonicus URM5620 Using Waste from Castor Bean (Ricinus communis L.) Under Solid-State Fermentation

The activity of beta-glucosidase (beta G), total cellulase (FPase) and endoglucanase (CMCase), produced by Aspergillus japonicus URM5620, was studied on solid-state fermentation using castor bean meal as substrate. The effect of the substrate amount, initial moisture, pH, and temperature on cellulase production was studied using a full factorial design (2(4)). The maximum beta G, FPase, and CMCase activity was 88.3, 953.4, and 191.6 U/g dry substrate, respectively. The best enzyme activities for all three enzymes were obtained at the same conditions with 5.0 g of substrate, initial moisture 15% at 25 A degrees C and pH 6.0 with 120 h of fermentation. The optimum activity for FPase and CMCase was found at pH 3.0 at an optimum temperature of 50 A degrees C for FPase and of 55 A degrees C for CMCase. The cellulases were stable in the range of pH 3.0-10.0 at 50 A degrees C temperature. The enzyme production optimization demonstrated clearly the impact of the process parameters on the yield of the cellulolytic enzymes.