Bioethanol Production from Coconut Husk Using Alkaline Pretreatment and Acid Hydrolysis

Abstract

This study investigates the potential of coconut husk (Cocos nucifera) as a feedstock for bioethanol production, focusing on the effects of alkaline pretreatment with potassium hydroxide (KOH) and acid hydrolysis with sulfuric acid (H₂SO₄) on ethanol yield. The coconut husk was subjected to 5% KOH pretreatment followed by acid hydrolysis with 4% and 5% H₂SO₄, enhancing cellulose accessibility and releasing fermentable sugars. Fermentation using Saccharomyces cerevisiae was performed at 37°C for varying periods (5 to 11 days). The highest ethanol yield of 5.72% was achieved after 11 days of fermentation with 5% H₂SO₄. Physicochemical analysis of the bioethanol produced showed properties within expected ranges for fuel-grade ethanol. These results highlight the viability of coconut husk as a sustainable, cost-effective raw material for bioethanol production, offering a renewable energy source while addressing agricultural waste management.