Hydrolysis of rice hull by crosslinked Aspergillus niger cellulase

A.niger cellulase was crosslinked by glutaraldehyde to obtain a heat-stable enzyme preparation for rice hull cellulose hydrolysis. Under optimized crosslinking conditions of 0.12 M glutaraldehyde, pH 7.0, temperature 40°C and at 45 min of crosslinking, a preparation having 15% more activity than free enzyme was obtained which also had considerable improvement in heat stability at 65°C and 70°C. Whereas the free enzyme lost 80% of its activity in 4 h at 65°C, the crosslinked preparation lost only 30% activity. The crosslinked preparation hydrolyzed cellulosic biomass more effectively giving 2.2 mg/ml glucose and 52% corresponding saccharification in 4 h at 65°C as compared to 14% saccharification by free enzyme under similar conditions.