β-Glucosidase, Bacteroides fragilis (EC 3.2.1.21), is a glucosidase enzyme that targets the β1→4 glycosidic bonds between two glucose molecules or glucose-substituted molecules, such as cellobiose. It serves as an exocellulase and exhibits specificity for various β-D-glucoside substrates. β-Glucosidase catalyzes the hydrolysis of the non-reducing terminal residues of β-D-glucosides, releasing glucose.