Dynamics of lignocellulose degradation by acid: Kinetic insights into high-solid acid pretreatment at normal...

Conventional acid pretreatment at high temperatures (>100 °C) and low solid-liquid ratios, often leads to excessive inhibitor formation. In this study, a high-solid, normal-temperature acid (HSNTA) pretreatment was developed to enhance digestibility while minimizing inhibitor generation. Corn stover was pretreated at 50 °C for 14 days with a solid-liquid ratio of 1.30 (56.5 % w/w solid loading), resulting in a total sugar recovery of 90.9 %. Enzymatic hydrolysis yielded 89.5 % glucan and 81.2 % xylan conversion. Kinetic analysis revealed that, under high-solid conditions, cellulose was primarily hydrolyzed into gluco-oligomers due to limited acid diffusion constraints. Xylan exhibited biphasic degradation comprising fast- and slow-reacting fractions, while lignin degradation was selective, occurring mainly in accessible regions. Kinetic models were established to quantitatively interpret the degradation behavior of individual components. These findings highlight the unique challenges and dynamics of biomass degradation under high-solid, normal-temperature conditions, addressing the importance of optimizing pretreatment parameters to maximize sugar yield.