Abstract
Pretreatment is an essential step in the production of alcohol from lignocellulosic-based materials because the biomass structural complexity severely restricts enzymatic and microbial accessibility. Due to that factor, recalcitrance to saccharification was found to be the major limitation for conversion of lignocellulosic-based material to ethanol. This study aims to reduce the recalcitrance within the biomass through delignification process and thus enhancing the enzymatic hydrolysis for bioethanol production. Jatropha seeds have been pre-treated with ultrasonic during biodiesel reactive extraction process. The cellulose, hemicellulose and lignin content of the Jatropha seed were characterized using the standard van Soest method, which employs Neutral Detergent Fibre (NDF), Acid Detergent Fibre (ADF) and Acid Detergent Lignin (ADL) procedure. Cellulose is considered to be represented by the difference between ADF and ADL (ADF - ADL), and hemicellulose is the difference between NDF and ADF (NDF - ADF). After reactive extraction process, the seed cake still contains 26.28 % of total cellulose and hemicelluloses and the amount of lignin is significantly reduced. Non-crystalline (amorphous) structures were revealed for all samples and the surface morphology suggests that some of the lignocellulosic compound have been degraded during the pretreatment process. Crystallinity of compounds also decreased when tested by using X-Ray diffraction (XRD) method. This pretreatment introduces a potential reduction of the recalcitrance in lignocellulosic materials (lignin, cellulose and hemicelluloses) and also improves its suitability as bioethanol feedstock.
