Kinetic modeling analysis of maleic acid‐catalyzed hemicellulose hydrolysis in corn stover

Abstract Maleic acid‐catalyzed hemicellulose hydrolysis reaction in corn stover was analyzed by kinetic modeling. Kinetic constants for Saeman and biphasic hydrolysis models were analyzed by an Arrhenius‐type expansion which include activation energy and catalyst concentration factors. The activation energy for hemicellulose hydrolysis by maleic acid was determined to be 83.3 ± 10.3 kJ/mol, which is significantly lower than the reported E a values for sulfuric acid catalyzed hemicellulose hydrolysis reaction. Model analysis suggest that increasing maleic acid concentrations from 0.05 to 0.2 M facilitate improvement in xylose yields from 40% to 85%, while the extent of improvement flattens to near‐quantitative by increasing catalyst loading from 0.2 to 1 M. The model was confirmed for the hydrolysis of corn stover at 1 M maleic acid concentrations at 150°C, resulting in a xylose yield of 96% of theoretical. The refined Saeman model was used to evaluate the optimal condition for monomeric xylose yield in the maleic acid‐catalyzed reaction: low temperature reaction conditions were suggested, however, experimental results indicated that bi‐phasic behavior dominated at low temperatures, which may be due to the insufficient removal of acetyl groups. A combination of experimental data and model analysis suggests that around 80–90% xylose yields can be achieved at reaction temperatures between 100 and 150°C with 0.2 M maleic acid. Biotechnol. Bioeng. © 2008 Wiley Periodicals, Inc.