Maleic Acid-Butanol\nPretreatment to Enhance Cellulose\nAccessibility for Enzymatic Hydrolysis and Ethanol Production from\nOil Palm Empty Fruit Bunch

Pretreatment of lignocellulosic biomass is crucial yet\nchallenging\nfor sustainable energy production. This study focuses on enhancing\nenzymatic accessibility of cellulose in oil palm empty fruit bunches\nby optimizing pretreatment parameters to improve glucose and ethanol\nyields while reducing fermentation inhibitors. It evaluates the impact\nof maleic acid concentrations on biorefinery processes. High maleic\nacid concentrations (>25% w/w) may allow reuse and offer benefits\nover lower concentrations, such as enhanced delignification and increased\nsugar yield under milder conditions. Biomass undergoes pretreatment,\nenzymatic saccharification, and fermentation using Saccharomyces cerevisiae F118. Pretreatment with\n75% maleic acid (w/w) for 60 min at 180 °C effectively removes\nlignin and hemicellulose, increasing cellulose accessibility but results\nin 74.8% crystallinity, hindering saccharification. A 50% maleic acid\npretreatment yielded higher glucose (77.1%). Optimal ethanol production\nis achieved with 1% maleic acid pretreatment. However, the ethanol\nyield is negatively impacted by residual maleic acid on the solid\nmatrix.