Investigation on the potential of bioethanol synthesis from honeydew melon rind

Abstract

Honeydew melon rind is an abundant and low-cost fruit waste, which holds potential for glucose and eventual bioethanol synthesis. In this study, alkaline pre-treatment was introduced to break down the lignin structure before conducting acid hydrolysis to further breakdown the cellulosic components into glucose. The functional group of the pre-treated and raw samples were analysed using Fourier-Transform Infrared (FTIR) spectroscopy to evaluate the effectiveness of alkaline pre-treatment in lignin removal. Alkaline pre-treatment was found to effective in lignin removal from the rind, thus, improving the accessibility of cellulose and hemicellulose for acid hydrolysis. Using response surface methodology (RSM) based on the central composite design, a maximum glucose concentration of 9.847% w/v was obtained using an acid concentration of 6% w/v, a reaction temperature of 75°C for 60 minutes. The hydrolysate which was fermented using the Saccharomyces cerevisiae (baker’s yeast) revealed the presence of ethanol as the major product with some traces of impurities. This shows that honeydew melon rind has the potential as lignocellulosic biomass source for bioethanol synthesis.