Enhanced Pretreatment of Winery Solid Waste for High Reducing Sugar Yield

Abstract

An increasing quantity of Winery solid waste (WSW) generated annually is of environmental concern. This study was aimed to evaluate the pretreatment efficacy of winery waste for biogas production. Samples comprising mainly of grape pomace were collected from a winery in Stellenbosch, South Africa and subsequently pretreated using chemical (Alkaline hydrogen peroxide, AHP) and biological (cellulases and ligninases) methods. To assess their activity, ligninases and cellulases were further used to hydrolyze the pretreated samples both singly and in combination (cocktail). The results showed an increase in reducible sugar (23%) with the combined enzymes (2.06 mg/mL) compared to the individual enzymes (1.68 mg/mL). The AHP-pretreated biomass also gave higher (1.900 mg/mL) yields than non-AHP pretreated (0.102 mg/mL), indicating a significant effect on delignification and de-crystallinization of cellulose in the biomass. This optimization process had significant impact on the valorization of winery solid waste.