Optimal hydrolytic activity of beta-glucosidase from Dictyoglomus turgidum for the ginsenoside Rd was at pH 5.5 and 80 A degrees C, with a half-life of similar to 11 h. The enzyme hydrolysed beta-linked, but not alpha-linked, sugar moieties of ginsenosides. It produced the rare ginsenosides, aglycon protopanaxadiol (APPD), compounds Y, and Mc, via three unique transformation pathways: Rb-1 -> Rd -> F-2 -> compound K -> APPD, Rb-2 -> compound Y, and Rc -> compound Mc. The enzyme converted 0.5 mM Rb-2 and 0.5 mM Rc to 0.5 mM compound Y and 0.5 mM compound Mc after 3 h, respectively, with molar conversion yields of 100 %.