Identification of β-Glucosidase Activity of E nterococcus Faecalis CRNB-A3 in Airag and Its Potential to Convert Ginsenoside Rb1 from Panax Ginseng

Abstract

The objectives of this study were to isolate the lactic acid bacteria (LAB) exhibiting β-glucosidase activity from Airag, and investigate the hydrolytic activity of the enzyme on saponin (Korean ginsenoside). Of the 33 types of LAB with positive reactions (β-glucosidase) in the Esculin Iron Agar test, one LAB (CRNB-A3) was found to have high hydrolytic activity for ginsenoside Rb1. 16S rDNA analysis revealed that CRNB-A3 was Enterococcus faecalis (99.9% homology). The optimum temperature and pH for growth of CRNB-A3 in MRS broth were 35C and 8.0, respectively. Crude enzyme from E. faecalis CRNB-A3 showed ability to convert ginsenoside Rb1 into minor ginsenosides Rg3 and Rg5. The use of an API ZYM kit showed that E. faecalis CRNB-A3 had higher activities of leucine arylamidase, esterase and β-glucosidase than any other enzyme activities. Additionally, E. faecalis CRNB-A3 was identified as being hetero-fermentative. Practical Applications The fermentation of Panax ginseng yields many compounds from ginsenoside that have varying biological functions. These compounds are widely consumed in Korea and other Asian nations in the form of extracts, alcohols, candy, fermented liquids and pharmacological products. This study revealed that an Airag (Mongolian KOUMISS) LAB strain possessed a strong ability to convert ginsenoside Rb1 to Rg3 and Rg5, which could be used in food and cosmetic industries for making yogurts, beverage products, cosmetics and other products for ginsenoside supplementations.