The alkaline protease was successfully purified and characterized from the bacterium Serratia marcescens S3-R1, which has potential for industrial application, including milk protein hydrolysates.
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.
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 APPLICATIONSFermentation 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 healthpromoting functional properties of ginsenoside Rg3 and Rg5 would enhance the growth of the ginseng food industry.
Lentilactobacillus buchneri isolated from Korean fermented plant foods produces β-glucosidase, which can hydrolyze ginsenoside Rb1 from Panax ginseng to yield ginsenoside Rd. The aim of this study was to determine the mechanisms underlying the extracellular β-glucosidase activity obtained from Lentilactobacillus buchneri URN103L. Among the 17 types of lactic acid bacteria showing positive β-glucosidase activity in the esculin iron agar test, only URN103L was found to exhibit high hydrolytic activity on ginsenoside Rb1. The strain showed 99% homology with Lentilactobacillus buchneri NRRLB 30929, whereby it was named Lentilactobacillus buchneri URN103L. Supernatants of selected cultures with β-glucosidase activity were examined for hydrolysis of the major ginsenoside Rb1 at 40 °C, pH 5.0. Furthermore, the β-glucosidase activity of this strain showed a distinct ability to hydrolyze major ginsenoside Rb1 into minor ginsenosides Rd and Rg3. Lentilactobacillus buchneri URN103L showed higher leucine arylamidase, valine arylamidase, α-galactosidass, β–galactosidase, and β-glucosidase activities than any other strain. We conclude that β-glucosidase from Lentilactobacillus buchneri URN103L can effectively hydrolyze ginsenoside Rb1 into Rd and Rg3. The converted ginsenoside can be used in functional foods, yogurts, beverage products, cosmetics, and other health products.
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