Biotransformation of Ginsenoside Rb2 to Rg3 by Endophytic Bacterium Leifsonia sp.G05 isolated from Dry Panax ginseng

Abstract

Abstract In this study, a strain G05, which can efficiently convert the main ginsenoside Rb2 to the rare ginsenoside Rg3, was screened from the endophytic bacteria of dry Panax ginseng by thin layer chromatography (TLC) and high performance liquid chromatography (HPLC) analysis. The strain was identified as Leifsonia by morphological and molecular biological analysis and named Leifsonia sp.G05. The effect of medium, inoculum amount, transformation temperature, medium pH and substrate concentration on the conversion rate of ginsenoside Rb2 to Rg3 was investigated to obtained the optimum conditions for transformation and high conversion rate, as well as the transformation path of strain G05. The results showed that the strain G05 could convert 1 mg/mL ginsenoside Rb2 more efficiently when the medium was Luria-Bertani, the inoculum amount was 1%, the transformation temperature was 30°C, and the medium pH was 7. Under these conditions, the main ginsenoside Rb2 could be nearly completely converted to the rare ginsenoside Rg3 by strain G05 after 9 hours of fermentation, the conversion rate reached 98%, and the transformation path was Rb2→Rd→Rg3. The research results could improve the utilization rate of the main ginsenoside Rb2 to a certain extent, and provide safer and specific rare ginsenosides for the pharmaceutical and food preparation industries.