Specifically hydrolyzes the glucosidic linkage in glucosylceramide (PubMed:22072709). May prevent accumulation of aberrent glucosylceramide containing immature ceramide (PubMed:22072709). a beta-D-glucosyl-(1<->1')-N-acylsphing-4-enine + H2O = an N-acylsphing-4-enine + D-glucose Optimum pH is 7. Decreases membrane glucosylceramidase activity at neutral pH (PubMed:22072709). Increases cellular glucosylceramide levels; levels of normal glucosylceramide containing mature ceramide and abnormal glucosylceramide containing immature ceramide are both increased (PubMed:22072709). Decreases capsule size during growth in capsule-inducing conditions (PubMed:22072709). Belongs to the glycosyl hydrolase 5 (cellulase A) family. Extended N-terminus.