Media Optimization for Cellulase Production at Low Energy Consumption with Response Surface Methodology

The bottleneck of producing bioethanol from lignocellulosic materials is cost. This study adopted response surface methodology to optimize the cellulase production by Penicillium sp. CLF-S. Three variables of carbon nitrogen ratio, liquid-solid ratio, and buffer solution volume that have significant effects on the cellulase production were determined. After analyzing the results of full factorial central composite design, a quadratic polynomial model was established. The final optimal values of the three variables were as follows: carbon nitrogen ratio was 14.65 (mol:mol), liquid solid ratio was 34.36 (ml:g), and buffer solution was 13.29 ml per 100 ml media. The maximal cellulase activity could be up to 1,215.38 u/ml, which was 84.64% higher than the control value. The optimized coarse enzyme solution was extracted out of the cultivation system in order to decompose the corn stover, and the concentration of glucose (6.32 g/l) was 2.47 times that of hydrolysis with non-optimized cellulase.