Ethanol production from oil palm empty fruit bunch fiber prepared through pretreatment with sodium hydroxide under optimized conditions

Abstract

Alkali pretreatment of oil palm empty fruit bunch (OPEFB) using sodium hydroxide (NaOH) was optimized by varying substrate concentration, alkali loading, temperature, and time. A Central Composite Design (CCD) based on the Box–Wilson factorial design was applied to determine conditions that maximized cellulose and hemicellulose and minimized lignin to enhance ethanol production. Under optimized conditions, cellulose reached 65.2%, while lignin and hemicellulose were reduced to 9.4% and 11.8%, respectively. Pretreated OPEFB released high amounts of fermentable sugars, with glucose, xylose and arabinose yields of 43.4 ± 0.2, 28.1 ± 0.1 and 10.2 ± 0.3 mg/g, respectively, representing a clear increase compared with low-alkali conditions. Fermentation of the optimized biomass produced a maximum ethanol concentration of 60.8 g/L.