Production of the Rare Ginsenosides Compound K, Compound Y, and Compound Mc by a Thermostable beta-Glycosidase from Sulfolobus acidocaldarius

摘要

The rare ginsenosides compound K, compound Y, and compound Mc were produced from the major ginsenosides Rh-1, Rb-2, Rc, and Rd by a thermostable beta-glycosidase from Sulfolobus acidocaldarius via three pathways: Rb-1→ Rd → compound K, Rb-2 →compound Y → compound K, and Rc →compound Mc. Each of the ginsenosides was identified by high-performance liquid chromatography using standards and liquid chromatography-mass spectrometry based on their molecular weights. The catalytic efficiency of the enzyme for ginsenosides followed the order Rb-1 (4.8)>Rc (4.5)>Rd (1.0)>Rb_2 (0.77 mM~(-1) min~(-1)). The enzyme converted 1 mg/ml reagent-grade Rb-1, Rb-2, and Re to 0.53 mg/ml compound K, 0.56 mg/ml compound Y, and 0.70 mg/ml compound Mc, respectively, at pH 5.5 and 85 degrees C after 180 min, corresponding to mole conversion yields of 94, 80, and 100% (mol/mol), respectively. The enzyme converted the major ginsenosides Rb_1, Rb_2, Rc, and Rd in 10% (w/v) ginseng root extract to the rare ginsenosides with a mole yield of 99% after 24 h. These results suggest that beta-glycosidase from S. acidocaldarius can be used to produce compound K, compound Y, and compound Mc.