Specifically hydrolyzes the glucosidic linkage in glucosylceramide (PubMed:22072709). May prevent accumulation of aberrent glucosylceramide containing immature ceramide (By similarity). a beta-D-glucosyl-(1<->1')-N-acylsphing-4-enine + H2O = an N-acylsphing-4-enine + D-glucose Belongs to the glycosyl hydrolase 5 (cellulase A) family.