EFFECTS OF GREEN LIQUOR PRETREATMENT ON ENZYMATIC SACCHARIFICATION OF CORN STOVER

摘要

Green liquor consists of sodium carbonate and sodium sulfide and is readily available in any kraft mill. The liquor can be used to pretreat corn stover to enhance the enzymatic hydrolysis for bioethanol production. The green liquor pretreatment process for bioethanol production was developed at North Carolina State University for wood chips. The process uses only proven technology and equipment currently used in a kraft pulp mill and has several additional advantages such as higher sugar recovery at high sugar concentration, no inhibitive substances produced, etc, as compared to other acid-based pretreatment methods. It was used in this study and found that corn stover required much lower alkali charge and temperature than either hardwood or softwood. The pulp yield of 70% with 45% lignin removal was achieved under optimized conditions (8% TTA, 40% sulfidity and 140°C). About 70% of the original polysaccharide was converted into fermentable sugars, using 20 FPU/g of enzyme in the subsequent enzyme hydrolysis.