Naturally occurring ginsenoside F1 (20-O-β-D-glucopyranosyl-20(S)-protopanaxatriol) is rare. Here, we produced gram-scale quantities of ginsenoside F1 from a crude protopanaxatriol saponin mixture comprised mainly of Re and Rg1 through enzyme-mediated biotransformation using recombinant β-glucosidase (BgpA) cloned from a soil bacterium, Terrabacter ginsenosidimutans Gsoil 3082T. In a systematic step-by-step process, the concentrations of substrate, enzyme, and NaCl were determined for maximal production of F1. At an optimized NaCl concentration of 200 mM, the protopanaxatriol saponin mixture (25 mg/ml) was incubated with recombinant BgpA (20 mg/ml) for 3 days in a 2.4 L reaction. Following octadecylsilyl silica gel column chromatography, 9.6 g of F1 was obtained from 60 g of substrate mixture at 95% purity, as assessed by chromatography. These results represent the first report of gramscale F1 production via recombinant enzyme-mediated biotransformation.
Keywords: Protopanaxatriol; bioconversion; glycoside hydrolase family 3; gram-scale; rare ginsenoside.