Fruit Residues as Biomass for Bioethanol Production Using Enzymatic Hydrolysis as Pretreatment

Abstract The commercialization of fruits in the market generates a large amount of waste because they are perishable and have a short shelf life; thus, they are discarded. This study aimed to provide a noble end to discarded fruits that have fermentable sugars. These fruits were collected from supermarkets in the city of Passo Fundo, Brazil, and underwent an enzymatic hydrolysis process. The ability of four pectinases, two amylases, one xylanase and one cellulase to release reducing sugars from fruit biomass before fermentation with two yeast strains (S. cerevisiae CAT-1 and S. cerevisiae Angel) for bioethanol production was investigated, obtaining a total of RS (Reducing sugar) of 359.38 mg/L. A fermentation with yeast S. cerevisiae CAT-1 resulted in 98% consumption of RS and the production of a total of 28.02 g/L of ethanol. Furthermore, fermentation with the yeast S. cerevisiae Angel, resulted in 97% RS consumption and 31.87 g/L ethanol production, which was the best result obtained throughout all the tests of hydrolysis.