earticle

영어

The β-xylosidase (EC 3.2.1.37) production capabilities of lactic acid bacteria in the genus Leuconostoc, isolated from a variety of kimchi (fermented vegetables), were examined. The intracellular levels of β-xylosidase were similar to the extracellular levels, when most Leuconostoc lactic acid bacteria were grown in a medium containing xylose as the carbon source. Intracellular β-xylosidase with a maximum activity of 1.2±0.1 units/mL (mean±standard error) was obtained from Leuconostoc lactis KCTC 13344, which was isolated from fermented Chinese cabbage. The optimum reaction conditions for Leu. lactis KCTC 13344 β-xylosidase activity were pH 6.0 and 30oC, and the addition of most divalent cations, except zinc, to the reaction mixture resulted in a slight increase in enzyme activity. Compared with a media containing other carbon sources, the β-xylosidase activity was 5 times higher when Leu. lactis KCTC 13344 was grown in a medium containing xylose as carbon source. Zymographic analysis indicated that the synthesis of Leu. lactis KCTC 13344 β-xylosidase (approximate size, 64 kDa) is induced by xylose. A maximum intracellular β-xylosidase activity of 7.1±0.3 units/mL was obtained in a batch cultivation in an MRS medium containing 30 g/L xylose.