Microwave-assisted alkaline pretreatment of white grape pomace for the production of bioethanol

Abstract

Grape pomace is a suitable substrate for bioethanol production as it contains carbohydrates and various amino, but its high lignin content hinders productivity. Microwave-assisted alkaline pretreatment was performed in this study to selectively remove the lignin and the pretreatment conditions (alkaline concentration, temperature, and reaction time) were optimized by the response surface method (RSM). NaOH concentration and temperature were determined to be factors that significantly impact the subsequent bioethanol production, while reaction time showed less impact. The highest delignification of 83.69% was achieved with 3% NaOH at 90 °C for 45 minutes, and the corresponding ethanol concentration reached 20.98 g L⁻¹ with a yield of 90.61%. This study developed an efficient pretreatment process for the biological conversion of grape pomace, providing support for the sustainable utilization of agricultural waste.