Characteristics of sugarcane bagasse fibers after xylan extraction and their high-solid hydrolysis cellulase-catalyzed

Abstract

The enzymatic hydrolysis of sugarcane bagasse to obtain a high efficiency conversion of polysaccharides in monosaccharides is dependent on factors related to the morphology and chemical composition. Therefore, a pre-treatment step is necessary to obtain a less recalcitrant substrate. Here, alkaline sulfite with ethanol (ASE) was employed to pretreat sugarcane bagasse aiming to produce substrates enriched in carbohydrates with greater cellulose accessibility. A xylanase stage was evaluated as a strategy to remove arabinoxylan fraction from pretreated bagasse and to verify the influence of the addition of the enzyme xylanase (5, 50, and 500 IU/g material) on the characteristics of ASE pretreated bagasse from 5 to 15% dry matter. The highest xylan extraction yield of 59% was achieved when working at 15% solids and xylanase dosage of 500 IU/g substrate. The interaction of enzyme and solid loadings was positive to arabinoxylan extraction, however the excessive removal of arabinoxylans caused changes on biomass fiber surface and a decrease in water absorption. The cellulase-catalyzed hydrolysis of ASE bagasse ASE pre-extracted by xylanase was nearly paralleled to the control sample, at 15% solids. This study shows that the enzymatic removal of xylan from pretreated bagasse provides a promising condition for the generation of the value-added product in the biorefinery process.