Investigation of the Effect of Supercritical Carbon Dioxide Pretreatment on Sugar Yield Prior to Enzymatic Hydrolysis of Empty Fruit Bunches

Abstract Supercritical carbon dioxide (SC-CO2) pretreatment of empty fruit bunches (EFBs) was investigated for its effect on glucose yield following enzymatic hydrolysis. The SC-CO2 pretreatment of EFBs was performed under various conditions: temperature of 80°C or 130°C; pressure of 150, 200, or 250 bar; moisture content of 0% or 75%; and time of 30 min or 60 min. The SC-CO2-pretreated EFBs were hydrolyzed using a combination of the enzymes Celluclast 1.5L and Novozyme 188 (Sigma Aldrich, St. Louis, MO) . The chemical compositions of untreated EFBs (% g/g dry biomass) were recorded as 36.7% cellulose, 22.8% hemicellulose, and 24.2% klason lignin. The optimal chemical composition of EFBs for SC-CO2 pretreatment were 38%, 25.5%, and 23.8% for cellulose, hemicellulose, and klason lignin, respectively. After enzymatic hydrolysis, the glucose yield of untreated EFBs was 17% (17 g/100 g dry biomass). SC-CO2 pretreatment of EFBs for 60 min at 75% moisture content, 130°C, and 250 bar pressure gave the highest gl...