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.