Passion fruit peel as novel substrate for enhanced β-glucosidases production by Penicillium verruculosum: Potential of the crude extract for biomass hydrolysis

β-Glucosidases show great potential as catalysts for various biotechnology processes including biomass hydrolysis for bioethanol production. In this study, response surface methodology was used to evaluate the effect of some variables on β-glucosidase production by Penicillium verruculosum using passion fruit peel as substrate, and on hydrolysis of this process residue with P. verruculosum crude extract, by applying a full factorial central composite design. Process optimization resulted in a 5.7 fold increase in β-glucosidase activity. The enzymes were more active at 65 °C, pH 4.5, remaining stable at 55 and 60 °C and over a broad pH range. P. verruculosum crude extract hydrolyzed passion fruit peel with glucose yield of 45.54%. This article provides, for the first time, the production of remarkable yields of β-glucosidase and the achievement of expressive levels of glucose through the use of passion fruit peel, an abundant and inexpensive agro-industrial residue.