Degradative Ability of Yeast Isolates and Bioethanol Production from Ripe Fruit Peels of Pawpaw, Banana, Watermelon, Pineapple and Lime

Fruit peels are major components of agricultural wastes. As fruits peels undergo yeast-mediated degradation to produce bioethanol, they contribute to remediate the environment with potential industrial advantage. Hence, the objective of paper was to investigate the degradative ability of yeast isolates from ripe fruit peels of pawpaw, pineapple, banana, watermelon and lime for bioethanol production using appropriate standard methods. The medium for biodegradation of the fruit peels increased in turbidity after 6 weeks of the test. Pawpaw peels produced the highest amount of ethanol 36% (v/v) upon biodegradation with Pichia kudriavzevii NWB5-1, while the lowest ethanol yield was from watermelon peel (3%). Saccharomyces cerevisiae performed better than other isolates and attained a cumulative weight loss of 14%. Measured parameters for bioethanol produced including colour, relative density, melting point, boiling point, viscosity, refractive index and flash point are comparable with values from commercially available ethanol. This study underscores the economic value of fruit peels and prospective role of yeast as excellent biodegraders with potential industrial importance.