Production of biofuel (Bio-ethanol) from fruitwaste: Banana peels

Abstract

Bio-ethanol, a type of biofuel, is known as renewable energy source as it is derived from biomass as its raw material. Biomass can be found in abundance and sustainable i.e. sources are available continuously, unlike the currently used conventional fossil fuels where these sources are limited and depleting. In this study, biomass from fruit waste, banana peels, were utilized to produce bio-ethanol via hydrolysis and fermentation process. Banana peels, a lignocellulosic biomass, possesses compositions which favour these processes, where the banana peels are rich in cellulose content and low in lignin content. Mechanical pre-treatment of the banana peels was conducted to further ease the hydrolysis process by reducing the particle size of the biomass. Hydrolysis was carried out for 24 hours at 50ºC at different pH using sulfuric acid H2SO4 acid and sodium hydroxide NaOH as the base, to study the effect of pH on the hydrolysis process and hence the final bio-ethanol production, in terms of concentration. Fermentation of the hydrolysis products were carried out using glucose-yeast broth for 4 days at temperature of 35ºC. Water content in the bio-ethanol product from fermentation process was separated using rotary evaporator, prior to ethanol analysis using Gas Chromatography (GC-MS). Concentration of ethanol was found to be the highest at acidic pH conditions; pH 4 to 6. Lowest ethanol concentration was recorded at higher pH values, indicating alkaline conditions do not favour the hydrolysis process.