Oil Palm Trunks as Raw Material for Bioethanol Production: A Study on the Delignification Efficiency of Betaine-Based Natural Deep Eutectic Solvents

Non-productive oil palm trunks (OPT), rich in starch and cellulose, are promising raw materials for bioethanol production. Effective pretreatment is essential to optimize the cellulose-to-lignin ratio, facilitating hydrolysis. This study investigates the delignification efficiency of natural deep eutectic solvents (NaDES) on OPT, focusing on the impact of different hydrogen donors. Using a 1:2 ratio of hydrogen bond acceptor to donor and maintaining consistent reaction conditions, betaine/lactic acid and betaine/glycerol NaDES achieved optimal delignification, reducing lignin by 26.73% and 26.46%, respectively, at 100°C for 2 hours. The treated biomass was analyzed using FTIR, SEM, and XRD, confirming the effectiveness of these NaDES in lignin degradation. The results demonstrated that both betaine/lactic acid and betaine/glycerol, are natural solvent with significant potential for breaking down lignin in non-productive oil palm trunks. The findings suggest that betaine-based NaDES are promising for enhancing bioethanol production from oil palm trunks through efficient delignification.