COMPARATIVE STUDIES OF BIOETHANOL PRODUCTION FROM LIGNOCELLULOSIC FEEDSTOCKS FROM AGRICULTURAL WASTE

Abstract

With the increasing global focus on climate change and the depletion of fossil fuels, bioethanol production has emerged as a promising alternative to traditional petroleum fuels. This study compares eight locally available lignocellulosic feedstocks including sugarcane bagasse, rice husk, maize husk, apple pomace, cassava peel, banana stem, jackfruit peel and cotton fibres, for bioethanol production using Saccharomyces cerevisiae. The experimental work investigates the impact of pre-treatment with Ca(OH)2 for mitigating the inhibitory effects of furfural, which is a by-product of dilute acid hydrolysis pre-treatment. All the lignocellulosic feedstocks were evaluated for their ethanol yields, furfural content, and glucose utilisation under laboratory scale batch fermentation conditions. Among the feedstock sources, the maximum amount of ethanol was produced from rice husk (11.50 g/L), maize husk (11.54 g/L), and sugarcane bagasse (12.63 g/L). Apparent ethanol productivity values ranged between 0.282 g/L/day to 0.902 g/L/day with sugarcane bagasse showing highest productivity and furfural concentration was drastically reduced by 80.4%. This study was extended to 14 days to observe comparative insights on the suitability of the lignocellulosic feedstocks from agricultural waste residues, inhibitor reduction and laboratory scale process feasibility. Fourier Transform Infrared Spectroscopy (FTIR) qualitatively confirmed the presence of ethanol associated functional groups in all the distilled samples. The production of bioethanol in this study suggested predominantly non-growth associated product based on mathematical modelling.