Efeito do pré-tratamento ultrassônico em resíduos agroindustriais para liberação de açúcares fermentescíveis

Abstract

Given the increasing demand for sustainable energy sources drives the search for renewable alternatives. In this context, the use of agro-industrial residues, rich in structural carbohydrates and commonly discarded, to produce biofuels as a promising alternative. Composed of peels and parts of fruits and vegetables, these residues contain sugars bound in cellulose and hemicellulose chains, which hinders their availability to fermentative microorganisms responsible for biogas production. Therefore, it becomes necessary to apply pretreatments that promote the conversion of these polysaccharides into fermentable sugars. This study aimed to evaluate the application of probe type ultrasonic pretreatment, followed by enzymatic hydrolysis, to release fermentable sugars. Ultrasound treatment times were tested of 5, 10, 15, 20, 25, and 30 minutes. The conditions of ultrasonic time as 10 minutes combined with enzymatic hydrolysis using the cellulase (Celluclast) and alpha-amylase resulting in the highest concentration of glucose (18,494.73 mg/L) and xylose (13,665.22 mg/L). However, this same condition showed the concentrations of hydroxymethylfurfural (HMF) and furfural, which are potentially inhibitory compounds in the anaerobic digestion process. It is concluded that ultrasound is an effective pretreatment method for promoting sugar release from lignocellulosic residues, although controlling the formation of inhibitors is necessary.