Biotransformation of Major Ginsenoside Rb 1 to Rd by Dekkera anomala YAE-1 from Mongolian Fermented Milk (Airag)

J Microbiol Biotechnol. 2020 Oct 28;30(10):1536-1542. doi: 10.4014/jmb.2004.04022.

Abstract

Dekkera anomala YAE-1 strain separated from "airag" (Mongolian fermented mare's milk) produces β-glucosidase, which can convert ginsenoside Rb1 from Panax ginseng. Ginseng-derived bioactive components such as ginsenoside Rb1 have various immunological and anticancer activities. Airag was collected from five different mare milk farms located near Ulaanbaatar, Mongolia. YAE-1 strains were isolated from airag to examine the hydrolytic activities of β-glucosidase on Korean Panax ginseng using an API ZYM kit. Supernatants of selected cultures having β-glucosidase activity were examined for hydrolysis of the major ginsenoside Rb1 at 40°C, pH 5.0. The YAE-1 strain was found to be nearly identical at 99.9% homology with Dekkera anomala DB-7B, and was thus named Dekkera anomala YAE-1. This strain exerted higher β-glucosidase activity than other enzymes. Reaction mixtures from Dekkera anomala YAE-1 showed great capacity for converting ginsenoside Rb1 to ginsenoside Rd. The β-glucosidase produced by Dekkera anomala YAE-1 was able to hydrolyze ginsenoside Rb1 and convert it to Rd during fermentation of the ginseng. The amount of ginsenoside Rd was highly increased from 0 to 1.404 mg/ml in fermented 20% ginseng root at 7 days.

Keywords: Dekkera anomala YAE-1; Fermented mare's milk; airag; ginsenoside; β-glucosidase.