Identification of β-Glucosidase Activity of L actobacillus plantarum CRNB22 in Kimchi and Its Potential to Convert Ginsenoside Rb1 from P anax Ginseng

Abstract

This study involved isolating lactic acid bacteria (LAB) that exhibit β-glucosidase activity from kimchi and examining the hydrolytic activity of the enzyme on saponin. Of the 28 types of LAB found in Korean kimchi that 6 strains exhibited positive β-glucosidase activity based on the esculin iron agar test, only CRNB22 strain was able to hydrolyze ginsenoside Rb1. The crude enzyme from this kimchi LAB strain showed strong ability to convert ginsenoside Rb1 into Rg3 and Rg5. This isolated strain was identified as Lactobacillus plantarum via an API 50 kit and 16S rDNA analysis (99.9% homology) and was therefore named Lactobacillus plantarum CRNB22. The optimum incubation conditions for L. plantarum CRNB22 were found to be 40C at pH 7.0 in de Man–Rogosa–Sharpe (MRS) broth. L. plantarum CRNB22 was further identified to be a hetero-fermentative bacterium, producing mostly oxalic and lactic acids after 72 h of incubation in 10% reconstituted skim milk. Practical Applications Fermentation of Panax ginseng can yield many compounds converted from ginsenoside that have various biological functions compared with nonfermented ginseng. These compounds are widely consumed in Korea and Asian countries in the form of extracts, alcohols, candy, fermented liquids and pharmacological products. This present study has shown that a kimchi lactic acid bacteria strain has a strong ability to convert ginsenoside Rb1 into Rg3 and Rg5, and the strain can be used to manufacture yogurts, beverages, cosmetics and other products that are supplemented with ginsenosides. It is expected that the demonstration of health-promoting functional properties of ginsenoside Rg3 and Rg5 would enhance the growth of the ginseng food industry.