Exploration of β-Glucuronidase Activity of Lactic Acid Bacteria Isolated from Kimchi

Lactic acid bacteria (LAB) isolated from kimchi were studied for their ${\beta}$-glucuronidase activity. Among the 156 strains tested, 52 strains utilized glucuronic acid as a carbon source and their intracellular ${\beta}$-glucuronidase activities were significantly higher than their extracellular activities. Leuconostoc mesenteroides KFRI 73007 isolated from turnip kimchi exhibited the highest intracellular ${\beta}$-glucuronidase activity of $0.77{\pm}0.01U/mg$ protein, which was further increased to $1.14{\pm}0.01U/mg$ protein under optimized reaction conditions (pH 7, $37^{\circ}C$). The activity of ${\beta}$-glucuronidase was notably decreased by the addition of divalent cations, and glucuronic acid was the best carbon source to produce ${\beta}$-glucuronidase in Leu. mesenteroides KFRI 73007.

김치에서 분리된 젖산균의 β-glucuronidase 활성 탐색

전통발효식품인 김치에서 분리된 젖산균으로부터 ${\beta}$-glucuronidase 효소활성이 높은 균주를 선발하였다. 김치에서 분리된 156점의 젖산균 중 52점의 균주가 glucuronic acid를 탄소원으로 대사하였으며, 대부분의 젖산균은 세포내 ${\beta}$-glucuronidase 활성이 세포외 활성보다 유의적으로 높았다. 순무김치에서 분리된 Leu. mesenteroides KFRI 73007 균주가 $0.77{\pm}0.01U/mg$ protein로서 가장 높은 세포내 ${\beta}$-glucuronidase 효소활성을 나타내었다. 최적 반응조건은 pH 7, $37^{\circ}C$이었으며 $1.14{\pm}0.01U/mg$ protein의 효소활성을 나타냈다. 양이온 금속이온은 ${\beta}$-glucuronidase 효소활성을 약 70% 이상 저해하였으며, 균주 배양에 사용한 탄소원 중 ${\beta}$-glucuronidase 생산을 위한 최적의 탄소원은 glucuronic acid이었다.