(803c) Maximize Enzymatic Saccharification and Minimize Sugar Degradation in SPORL Pretreatment of Douglas-Fir At a Low Temperature: A Kinetic Approach

Maximize sugar yield and minimize inhibitor formation are often difficult to achieve simultaneously in pretreatment of lignocelluloses.  The objective of this work was to evaluate the hemicellulose hydrolysis and degradation models with the goal of predicting performance of both hydrolysis and degradation process and optimizing the pretreatment conditions. Various investigations have developed reaction rate expressions based on Arrhenius and first order rate law. Based on the experiment data, the hemicellulose hydrolysis and degradation kinetic models were developed and the best-fit kinetic parameters were determined. The kinetic models showed that the hemicellulose degradation reaction was more sensitive to pretreatment temperature compared with hydrolysis reaction during pretreatment process.  Under the same pretreatment severity expressed by the Combined Hydrolysis Factor (CHF) using SPORL (sulfite pretreatment to overcome recalcitrance of lignocelluloses), a low temperature pretreatment at 165°C for 75min can reduced the inhibitor generation compared with a pretreatment at 180°C for 30min while the substrate enzymatic digestibility was almost identical under these two conditions.