In order to efficiently produce high-bioactive minor ginsensoide C-K or F2, the protopanaxadiol(PPD) ginsenosides from American ginseng were converted by the enzyme from Aspergillus niger g.848 strain. The mass fractions of PPD ginsenosides were 49.6% Rb1, 25.9% Rd, 19.3% Rc and 5.23% Rb2, respectively. In fermentation, when the PPD-ginsenosides as a ginsenosidase-inducer, the 10%—15% ginsenosidase activity was increased than that of ginseng-extract ginsenosidase-inducer. The two enzymes were all the Ginsenosidase typ1-I. However, the enzyme by the ginsenosidase-inducer could hydrolyze almost PPD-ginsenosides into C-K, but the enzyme by ginseng extract-inducer hydrolyzed PPD-ginsenosides into F2, C-K, C-Mc and C-Y. When reacted for 1.5 h to 3 h, the main product was F2. When reacted for over 12 h, the main product was C-K. In the C-K preparation, 40 g of PPD-ginsenosides was reacted at 45 ℃ and pH=5.0 for 24 h to get 23 g product containing over 87%(mass fraction) C-K, the C-K molar yield was 85%. In the F2 preparation, 40 g PPD-ginsenosides was reacted at 45 ℃ and pH=5.0 for 2.5 h to get 26 g product containing 58%(mass fraction) of F2 and 27% of C-K, the molar yield was 50.4% for F2, and 29.5% for C-K. Therefore, according to biotransformation of the enzyme by PPD-ginsenosides-inducer, the 85% of C-K, or 50% of F2 was successfully prepared from PPD ginsenosides of American ginseng. The results are very usable for ginseng development.
