Production of Bioethanol from Fruit Peels using Yeast Fermentation

Abstract

The escalating generation of fruit waste presents both environmental and socio-economic challenges, particularly in developing countries like Nigeria, where improper disposal contributes to pollution and greenhouse gas emissions. Simultaneously, the rising demand for renewable energy has heightened interest in bioethanol as a sustainable alternative to fossil fuels. This study investigated the bioethanol production potential of mango (Mangifera indica), lemon (Citrus limon), and plantain (Musa paradisiaca) peels using Saccharomyces cerevisiae as the fermenting organism. Biochemical analysis revealed significant variability in substrate composition: mango peel exhibited the highest total sugar content (55.5%), followed by plantain (45.2%) and lemon (38.0%), while lemon peel contained the highest fibrous content and lowest pH, suggesting potential fermentation inhibitors. Correspondingly, mango peel produced the highest ethanol yield (12.5 mL/100 g; 5.8% v/v), outperforming plantain (10.2 mL/100 g) and lemon (7.1 mL/100 g). Fermentation efficiency mirrored these trends, with S. cerevisiae achieving 88.5% and 88.2% efficiency on mango and plantain peels, respectively, but only 72.2% on lemon peel. Kinetic analysis further demonstrated that mango peel reached maximum ethanol production in 72 hours, 25–40% faster than plantain and lemon peels, accompanied by the highest CO₂ production rate (15.2 mL/h), and indicating vigorous yeast metabolism. The study highlights the critical influence of substrate composition, inhibitory compounds, and fermentable sugar availability on bioethanol yield and fermentation dynamics. Mango peel emerges as the most promising feedstock for sustainable bioethanol production from fruit waste, with plantain as a viable alternative, while lemon peel requires pretreatment to mitigate inhibitory effects. These findings underscore the potential of valorizing fruit residues for renewable energy, contributing to environmental sustainability and the circular bioeconomy