Valorisation of Banana and Pineapple Peel Wastes for Sustainable Bioethanol Production: An Integrated Assessment of Fermentation Efficiency, Ethanol Quality, and Energy Recovery

Production of bioethanol from agricultural waste has become interesting owing to the growing need for sustainable fuel and environmental issues associated with the disposal of fruit waste. The aim of this research was to evaluate the potential of pineapple (Ananas comosus) and banana (Musa paradisiaca) peel as bioethanol production through acid hydrolysis and fermentation process using Saccharomyces cerevisiae. The dried fruit peel biomass (50 g) was hydrolysed with 1 M sulfuric acid and then fermented for seven days, and ethanol was recovered by distillation. Ethanol yield, sugar content, biomass conversion efficiency, sugar utilisation efficiency, ethanol quality, fermentation stability, and potential for energy recovery were measured. Both peels had an equal ethanol yield of 20.0%, corresponding to 10mL of ethanol from 50g of biomass. The sugar content of Pineapple peels was 2.80%, yielding better ethanol quality based on an ethanol density of 0.80 g/mL, a density deviation of 1.39%, and approaching the optimum pH (5.60 pH) for fermentation. But banana peel had a higher biomass conversion efficiency of 0.180 g ethanol/g biomass, a higher sugar utilisation efficiency of 10.00, and a higher energy recovery potential of 4.82 MJ/kg biomass. The composite performance evaluation data indicated that the overall performance of pineapple peel was 91.5%, while that of banana peel was 91.2%. From the study, it can be inferred that both wastes of the fruits, namely pineapple peel and banana peel, are very good raw materials for the production of bioethanol as second-generation feedstocks and that pineapple peel is good as a feedstock for better quality bioethanol, and banana peel is good as feedstock to achieve better biomass to energy conversion efficiency. The outcomes can be used for the sustainable valorisation of waste, the generation of renewables and the circular bioeconomy.