전통발효 식품으로부터 젖산균을 분리하고, β-glucosidase, β-glucuronidase, β-xylosidase, β-galactosidase, β-arabinofuranosidase, β-arabinosidase, β-arabinopyranosidase 등 생물전환과 관련된 유용 효소활성을 조사하였다. 효소활성 평가를 통하여 선발된 9점의 젖산균 발효에 의한 epigallocatechin-3-gallate(EGCG), epigallocatechin(EGC), epicatechin gallate(ECG), 및 epicatechin(EC)의 함량 변화를 조사하였다. 배추 김치에서 분리된 Leuconostoc mesenteroides MBE1424로 명명된 균주는 발효에 의하여 카테킨 중 EGC의 함량을 약 60% 증가시켰으며, 배양온도 40℃에서 가장 우수한 비성장속도를 나타내어 기존에 보고 된 균주보다 상대적으로 내열성이 우수한 것으로 판단되었다. Leuconostoc mesenteroides 균주는 녹차 추출물의 생물 전환에 필요한 유용한 효소계를 보유하고 있는 것으로 추정 되었다.

Hydrolytic enzyme activities, including those of β-glucosidase, β-glucuronidase, β-xylosidase, β-galactosidase, β-arabinofuranosidase, β-arabinosidase, and β-arabinopyranosidase, which are useful for bioconversion, were explored in lactic acid bacteria isolated from Korean traditional fermented foods. Nine bacterial strains were selected for the fermentation of green tea extract prepared by supercritical fluid extraction. Changes in the concentrations of catechin, epicatechin, epicatechin gallate, epigallocatechin, and epigallocatechin-3-gallate in green tea extract were investigated after fermentation by the selected lactic acid bacteria strains. The strain Leuconostoc mesenteroides MBE1424, which showed the highest β-glucuronidase enzyme activity among the tested bacterial strains, increased the epigallocatechin content of the green tea extract by 60%. In addition, L. mesenteroides MBE1424 was more resistant than the control strain at high temperature and showed a maximum specific growth rate at 40℃. L. mesenteroides MBE1424 was presumed to have an enzyme system containing β-glucuronidase with utility in the bioconversion of green tea extract.