Glucosidase involved in the degradation of cellulosic biomass. Has both alpha- and beta-glucosidase activity (By similarity). Hydrolysis of terminal, non-reducing (1->4)-linked alpha-D-glucose residues with release of alpha-D-glucose. Hydrolysis of terminal, non-reducing beta-D-glucosyl residues with release of beta-D-glucose. Belongs to the glycosyl hydrolase 31 family.