Optimization of Acid Treatment of Cashew Peduncle for Ethanol and Xylitol Production

Abstract

Due to the large amount of waste generated by industries and commitments for environment preservation, there has been a growing interest in the use of alternative energy sources for the production of bioproducts of added value such as ethanol and xylitol. In this context, cashew has been considered a promising alternative to meet the global demand in a more sustainable way. Thus, the aim of this study was to optimize the acid treatment of cashew peduncle for biotechnological production of ethanol and xylitol. Physicochemical analyseswere held for bagasse characterization, and sugars were assessed by HPLC (glucose, xylose and arabinose) and fermentation inhibitors (acetic acid, furfural and hydroxymethylfurfural) in the hydrolyzed liquor. The 2³+3 factorial experimental design was applied with a total of 11 experiments to investigate the influence ofvariables temperature, bagasse/acid diluted and acid concentration to evaluate the release of pentoses (xylose and arabinose) and hexose (glucose) in the hydrolyzed liquor. The liquor from the acid treatment should operate under ratio conditions temperature at level +1 (160 °C), acid concentration and bagasse:diluted acid at level -1 (1% and 1:6), obtaining pentose yields (xylose and arabinose). It was observed that acid treatment liquor is very effective in providing high-susceptibility substrates for ethanol and xylitol production.