(603d) Hydrolysis of Sucrose in Dilute Sulfuric Acid Solutions at Pretreatment Conditions for Lignocellulosic Biomass

Schell, D., National Renewable Energy Laboratory

Biomass represents an abundant renewable resource for the production of biobased products and biofuels. Lignocellulosic biomass consists of three main polymers: cellulose, hemicellulose and lignin. The bioconversion of lignocellulosic biomass requires two main processes: cellulose and hemicellulose conversion (hydrolysis) to monosaccharides, followed by fermentation of the monosaccharides into the desired product(s). In addition, lignocellulosic biomass sources such as agricultural residues (corn stover) and herbaceous materials (switchgrass) may contain appreciable amounts of sucrose. The aim of this study was to evaluate the amount of sucrose and its hydrolysis products, fructose and glucose, that remain after dilute sulfuric acid processing at reaction conditions typically used to pretreat lignocellulosic biomass. Solutions containing 25 g/L sucrose with 0.1% to 2.0% (w/w) sulfuric acid concentrations were treated at temperatures of 160°C to 200°C for 3 to 12 min. Sucrose was observed to completely hydrolyze at all treatment conditions. However, appreciable concentrations of fructose and glucose were detected and glucose was found to be significantly more stable than fructose. Different mathematical approaches were used to fit the kinetic parameters for acid-catalyzed thermal degradation of these sugars. Since both sugars may survive dilute acid pretreatment, they could provide an additional carbon source for production of ethanol and other bio-based products.