Development of an efficient pretreatment process for enzymatic saccharification of Eastern redcedar

► Hemicellulose and lignin removal occurred during acid bisulfite pretreatments. ► Delignification was important for improving glucose-to-glucan yields. ► Delignification of redcedar was increased by increasing sodium bisulfite loadings. ► Highest overall theoretical yield of wood glucan-to-glucose was 87%. This study investigates the potential for extracting sugars from the polysaccharides of Eastern redcedar. Pretreatment temperature, time, sulfuric acid loading, sodium bisulfite loading and impregnation time were varied using factorial treatment design experiments for identifying near optimal overall wood glucan-to-glucose yields during acid bisulfite pretreatments. The highest overall wood glucan-to-glucose yield of 87% was achieved when redcedar was impregnated with pretreatment liquor containing 3.75g of sulfuric acid/100g of dry wood and 20g of sodium bisulfite/100g of dry wood at 90°C for 3h followed by increasing the temperature to 200°C with a hold time of 10min. Hemicellulose and lignin removal during pretreatments made the substrate amenable to enzymatic hydrolysis using 0.5ml of Accelerase® 1500/g of glucan at 2% (w/w) solid loading. Preliminary mass balances showed 97% glucan recovery at pretreatment condition with 87% overall wood glucan-to-glucose yield and 59% delignification.