title: Enzymatic Biotransformation of Ginsenoside Rb1 and Gypenoside XVII into Ginsenosides Rd and F2 by Recombinant β-glucosidase from Flavobacterium johnsoniae.
abstract: This study focused on the enzymatic biotransformation of the major ginsenoside Rb1 into Rd for the mass production of minor ginsenosides using a novel recombinant β-glucosidase from Flavobacterium johnsoniae. The gene (bglF3) consisting of 2,235 bp (744 amino acid residues) was cloned and the recombinant enzyme overexpressed in Escherichia coli BL21(DE3) was characterized. This enzyme could transform ginsenoside Rb1 and gypenoside XVII to the ginsenosides Rd and F2, respectively. The glutathione S-transferase (GST) fused BglF3 was purified with GST-bind agarose resin and characterized. The kinetic parameters for β-glucosidase had apparent Km values of 0.91±0.02 and 2.84±0.05 mM and Vmax values of 5.75±0.12 and 0.71±0.01 μmol·min(-1)·mg of protein(-1) against p-nitrophenyl-β-D-glucopyranoside and Rb1, respectively. At optimal conditions of pH 6.0 and 37℃, BglF3 could only hydrolyze the outer glucose moiety of ginsenoside Rb1 and gypenoside XVII at the C-20 position of aglycon into ginsenosides Rd and F2, respectively. These results indicate that the recombinant BglF3 could be useful for the mass production of ginsenosides Rd and F2 in the pharmaceutical or cosmetic industry.
authors.affiliation: KAIST Institute for Biocentury, Korea Advanced Institute of Science and Technology, Daejeon 305-701, Korea ; College of Biotechnology, Dalian Polytechnic University, Dalian 116034, China.
authors.forename: Hao
authors.initials: H
authors.lastname: Hong
authors.forename: Chang-Hao
authors.initials: CH
authors.lastname: Cui
authors.forename: Jin-Kwang
authors.initials: JK
authors.lastname: Kim
authors.forename: Feng-Xie
authors.initials: FX
authors.lastname: Jin
authors.forename: Sun-Chang
authors.initials: SC
authors.lastname: Kim
authors.forename: Wan-Taek
authors.initials: WT
authors.lastname: Im
keywords: Biotransformation; Flavobacterium johnsoniae; Ginsenoside F2; Panax ginseng; β-glucosidase