Comparison of the enzymatic convertibility of glycerol- and sulfuric acid-pretreated sugarcane bagasse using different cellulase preparations

Three enzyme preparations based on the cellulase complex of Penicillium sp. and three Trichoderma-based commercial preparations were used for evaluating the enzymatic convertibility of cellulose contained in glycerol- and sulfuric acid-pretreated sugarcane bagasse. Initially, the hydrolysis of the bagasse substrates was monitored using a micro-scale method where the volume of the reaction mixture was 2 mL and the substrate concentration was 50 g/L. One of the Trichoderma preparations and the three Penicillium-derived ones displayed higher sugar formation and better cellulose conversion than the other two cellulases. The best performing preparations were used in a further investigation of the effect of the enzyme load. Increasing the load from 2 to 10 mg protein per g substrate improved the cellulose conversion but it did not increase the specific hydrolysis rate. The selected preparations were then assayed at a higher scale (20 mL of reaction mixture with a substrate concentration of 100 g/L). Regardless of the cellulase preparation and the experiment size, glycerol-pretreated bagasse had a better enzymatic convertibility than acid-pretreated bagasse. The Trichoderma-based commercial preparation Cellic CTec3 led to higher hydrolysis rates and conversions than the Penicillium-based laboratory preparations. Among the Penicillium sp. preparations, B1-Xyl PCA displayed rather good potential for hydrolysing acid-pretreated bagasse, and B1-Hist BGL had a comparable performance both in presence as in absence of A. niger b-glucosidase.