抄録
Ginsenoside compound K was produced from ginseng root extract using a thermostable recombinant β-glycosidase from Sulfolobus solfataricus. The pH and temperature for maximum production were 5.5 and 90 °C. The half-lives of the enzyme were 66, 30, and 1.7 h at 80, 85, and 90 °C respectively. The ginsenoside-hydrolyzing activity (Rd>Rb1>Rc>Rb2) and compound K-producing activity (Rd>Rc>Rb1>Rb2) of the β-glycosidase were also determined. At pH 5.5 at 85 °C, 1.63 mg/ml of compound K was produced within 12 h by 40 U/ml of enzyme from 1.9 mg/ml of ginsenoside Rb1, 0.52 mg/ml of ginsenoside Rb2, 0.92 mg/ml of ginsenoside Rc, and 0.23 mg/ml of ginsenoside Rd in a 10% (w/v) ginseng root extract via two transformation pathways, Rb1 or Rb2 → Rd → F2 → compound K, and Rc → compound Mc → compound K.
