Pretreatment of corn stover for sugar production using a two-stage dilute acid followed by wet-milling pretreatment process.

A two-stage process was evaluated to increase sugar recovery. Firstly, corn stover was treated with dilute hydrochloric acid to recover the xylose, and then the residue was subjected to a wet-milling pretreatment. Dilute hydrochloric acid showed a high xylose recovery during the first stage. The optimal condition was 120°C and 40min for 0.7wt% dilute hydrochloric acid pretreatment followed by wet-milling pretreatment for 15min. The xylose and glucose yield were 81.0% and 64.0%, respectively, with a cellulase dosage at 3FPU/g of substrate. This two-stage process was effective on account of the removal of hemicelluloses in the first stage and the delamination of cell wall in the second stage, increasing the possibility of adsorption of cellulose to enzymes, and resulting in a high sugar recovery with a very low enzyme loading.