earticle

영어

Three lactic acid bacteria (C-1, K-3 and T-1 strain) were isolated from Nuruk, and characterized subsequently. They were useful strains for production of lactic acid and their growth was inhibited at 10% ethanol, pH 4. These strains were identified as Lactococcus lactis subsp. lactis NR C-1, Leuconostoc mesenteroides subsp. mesenteroides NR K-3, and Pediococcus
pentosaceus NR T-1, respectively, by morphological, physiological and biochemical characterization. Lac. lactis subsp. lactis NR C-1 showed the highest lactic acid productivity. Leu. mesenteroides subsp. mesenteroides NR K-3 showed stable lactic acid productivity and its growth was inhibited at pH 4. P. pentosaceus NR T-1 had lower lactic acid productivity than the
other two bacteria, but it could not grow at 10% ethanol, pH 4. The lactic acid productivity of these three strains in MRS broth were higher than that in Skim milk media. The optimum pH and temperature for the lactic acid production of the three strains were 30～32℃ and pH 6.0～6.8. Glucose was the optimal carbon source for the lactic acid production. In terms of
antagonism, Lac. lactis subsp. lactis NR C-1 showed somewhat inhibitory effects against some Gram positive rod and cocci such as Lactobacillus brevis and Streptococcus mitis. And Leu. mesenteroides subsp. mesenteroides NR K-3 showed the inhibitory effects against Streptococcus mitis, but P. pentosaceus NR T-1 didn't show any inhibitory effects against tested
strains.

한국어

시판누룩으로부터 젖산 생성능력이 우수하고 10% 에탄올 및 pH 4부근에서 생육이 정지되는 젖산세균 C-1, K-3 와 T-1균주를 분리, 동정했다. 분리된 C-1균주를 Lactococcus lactis subsp. lactis NR C-1로, K-3균주를 Leuconostoc mesenteroides subsp. mesenteroides NR K-3로, 그리고 T-1균주를 Pediococcus pentosaceus NR T-1으로 각각 동정하였다. Lac. lactis subsp. lactis NR C-1균주와 P. pentosaceus NR T-1는 동형젖산발효로 젖산을 생성했으며, Leu. mesenteroides subsp. mesenteroides NR K-3는 이형젖산발효로 젖산을 생성하였다. 실험균주 모두 cell size는 0.7～2.0㎛
크기의 구균이 었다. Lac. lactis subsp. lactis NR C-1은 MRS 배지와 skim milk 배지에서 높은 젖산 생성능력을 나타내었으며, 분리 동정된 3균주 모두 skim milk 배지에서보다 MRS 배지에서 젖산 생성능력이 우수했다. 그리고 생육온도 30～32℃와 pH 6～7부근의 조건에서 분리균주 모두 높은 젖산 생성능력을 나타내었으며, 이들 젖산세균은 glucose를 이용하여 공통적으로 높은 젖산 생성능력을 나타내었다. Lac. lactis subsp. lactis NR C-1은 Gram양성세균인 Lactobacillus brevis와 Streptococcus mitis의 생육을, Leu. mesenteroides subsp. mesenteroides NR K-3는 Streptococcus mitis의 생육을 저해했다. 그러나 P. pentosaceus NR T-1은 실험에 사용된 모든 시험균주의 생육에는 아무런 영향을 미
치지 않았다.