Is able to catalyze the hydrolysis of aryl-phospho-beta-D-glucosides such as 4-methylumbelliferyl-phospho-beta-D-glucopyranoside (MUG-P), phosphoarbutin and phosphosalicin. Is not essential for growth on arbutin and salicin as the sole carbon source. 6-phospho-beta-D-glucosyl-(1->4)-D-glucose + H2O = D-glucose + D-glucose 6-phosphate Expressed at a low and constant level during growth, sporulation, and spore germination. Is not induced by aryl-beta-D-glucosides such as arbutin, salicin or 4-methylumbelliferyl-beta-D-glucopyranoside (MUG). Is not repressed by glucose. Belongs to the glycosyl hydrolase 1 family.