The influence of sorbitol on the production of cellulases and xylanases in an airlift bioreactor

The production of cellulases and xylanases by Penicillium echinulatum in an airlift bioreactor was evaluated. In batch production, we tested media with isolated or associated cellulose and sorbitol. In fed-batch production, we tested cellulose addition at two different times, 30 h and 48 h. Higher liquid circulation velocities in the downcomer were observed in sorbitol 10 g L−1 medium. In batch production, higher FPA (filter paper activity) and endoglucanase activities were obtained with cellulose (7.5 g L−1) and sorbitol (2.5 g L−1), 1.0 U mL−1 (120 h) and 6.4 U mL−1 (100 h), respectively. For xylanases, the best production condition was cellulose 10 g L−1, which achieved 5.5 U mL−1 in 64 h. The fed-batch process was favorable for obtaining xylanases, but not for FPA and endoglucanases, suggesting that in the case of cellulases, the inducer must be added early in the process.