β-Glucosidase 1A, Bacillus halodurans (EC 3.2.1.21), is a glucosidase that targets the β1→4 glycosidic bond between two glucose molecules or glucose-substituted molecules, such as in the disaccharide cellobiose. It is part of the cellulase family, enzymes that facilitate the breakdown of cellulose and related polysaccharides. Specifically, β-Glucosidase is an exocellulase with specificity for various β-D-glucoside substrates, catalyzing the hydrolysis of non-reducing terminal β-D-glucoside residues to liberate glucose.