Optimization of the simultaneous production of cellulase and xylanase by submerged and solid-state fermentation of wheat chaff

Abstract

Wheat chaff as an agricultural waste represents a cheap raw material for biotechnological processes. With its lignocellulosic composition, it is suitable for producing hydrolytic enzymes for second generation renewable fuel production technologies. The aim of this work was to optimize the process parameters (cultivation temperature 25?35?C, pH value 4?6 and cultivation time 3?7 days) of the cultivating fungi (Trichoderma reesei QM 9414) on a media based on wheat chaff by submerged and solid-state techniques, in order to enhance and compare the two types of simultaneous cellulase and xylanase production. Optimal conditions for the submerged fermentation were 29.65?C for temperature, pH 4.27 and 7 days of cultivation, while for the solid-state fermentation, the optimal conditions were 28.01?C, pH 6.00 and 7 days. The cellulolytic and xylanolytic activities of the obtained cultivation broth filtrates were 0.0535 and 0.1676 U mL-1 for the submerged fermentation, and 0.0407 and 0.1401 U mL-1 for the solid-state fermentation, respectively, and with a 26.77 and 13.39 % enhancement of enzyme activity for submerged fermentation, and a 22.96 and 42.66 % enhancement for solid-state fermentation, respectively, compared to the results obtained before optimization.