Glucansucrase is an enzyme classified as a glycoside hydrolase (GH) 70 family, which catalyzes the synthesis of glucooligosaccharides with a low molecular weight using sucrose as a donor of D-glucopyranose and maltose as a carbohydrate acceptor. In this study, glucansucrase-producing lactic acid bacteria strain was isolated from the fermented foods collected in traditional markets, and the optimum conditions for the oligosaccharide production were investigated. The strain CCK940 isolated from Chinese cabbage kimchi was selected as an oligosaccharide-producing strain due to its high glucansucrase activity, with 918.2 mU/mL, and identified as Leuconostoc lactis. The optimum conditions for the production of oligosaccharides using Leu. lactis CCK940 were to adjust the initial pH to 6.0, add 5% (w/v) sucrose and 10% (w/v) maltose as a donor and acceptor molecules, respectively, and feed 5% (w/v) sucrose at 4 and 8 h of cultivation. When Leu. lactis CCK940 was cultured for 12 h at optimum conditions, at least four oligosaccharides with a polymerization degree of 2-4 were produced.

Glucansucrase is an enzyme classified as a glycoside hydrolase (GH) 70 family, which catalyzes the synthesis of various glucans and glucooligosaccharides with a low molecular weight using sucrose as a donor of D-glucopyranose and maltose as a carbohydrate acceptor. Oligosaccharides are indigestiable carbohydrate with low calories, which have various positive effects on the health of intestinal track. In this study, oligosaccharide produced from Leuconostoc lactis CCK940 was purified and its prebiotics effect was investigated. Leuconostoc lactis CCK940 which isolated from Chinese cabbage kimchi produced oligosaccharide using 5%(w/v) sucrose as a donor and 3%(w/v) maltose as an acceptor. Oligosaccharide produced was purified using Bio-gel P2 column chromatography and DPs of the resulting oligosaccharide were ranged from 3 to 7. When the prebiotics effects of freeze dried oligosaccharide were examined, 1%(w/v) of purified oligosaccharide added to carbohydrate-free MRS showed good prebiotics effects on Lactobacillus plantarum KCCM 12116, L. reuteri KCTC40417, and Bifidobacterium animalis KCCM1209.

Ginseng (Panax ginseng) is frequently used in Asian countries as a traditional medicine. The major components of ginseng are ginsenosides. Among these, ginsenoside compound K has been reported to prevent the formation of malignancy and metastasis of cancer by blocking the formation of tumor and suppressing the invasion of cancer cells. In this study, ginsenoside Rb1 was converted into compound K, via secreted β-glucosidase enzyme from the Leuconostoc lactis DC201 isolated, which was extracted from Kimchi. The strain DC201 was suspended and cultured in MRS broth at 37℃. Subsequently, the residue from the cultured broth supernatant was precipitated with EtOH and then dissolved in 20 mM sodium phosphate buffer (pH 6.0) to obtain an enzyme liquid. Meanwhile, the crude enzyme solution was mixed with ginsenoside Rb1 at a ratio of 1:4 (v/v).The reaction was carried out at 30℃ and 190 rpm for 72 hours, and then analyzed by TLC and HPLC. The result showed that ginsenoside Rb1 was transformed into compound K after 72 hours post reaction.