전통발효식품인 재래간장에서 fibrinolytic enzyme를 생산하는 미생물을 분리하였고 산업적으로 활용하기 위해 분리된 미생물 중 fibrinolytic enzyme 활성이 우수한 YJ11-21 균주를 선발하였다. YJ11-21을 분자수준에서 16S rDNA 유전자 염기서열을 분석한 결과, Bacillus licheniformis로 동정되었다. Fibrinolytic enzyme 생산을 위한 최적 배양조건으로서 탄소원은 glucose, 질소원은 yeast extract를 첨가하였을 때 가장 높게 나타났다. 그리고 1% NaCl를 첨가한 배지에서 혈전용해 효소활성이 가장 높게 나타났고, 10% NaCl에서도 높은 효소활성과 생장률 또한 양호하여 YJ11-21는 내염성균으로 추정된다. YJ11-21를 $30^{circ}C$에서 배양시 가장 높은 효소 활성과, 초발 pH 5-10까지 안정한 효소활성을 보였다. 그리고 pH 9에서 가장 높은 혈전용해 효소활성과 균주의 생장률이 나타났다.
Bacterial strains exhibiting fibrinolytic activity were screened from traditional Korean soybean sauce. The Fibrinolytic activities of the various isolated microorganism were further examined and the superior strain YJ11-21 was selected for further analyses. Gene sequence analysis of 16S rDNA of the YJ11-21 strain revealed Bacillus licheniformis. Optimal culture conditions were investigated in order to maximize the production of the fibrinolytic enzyme by YJ11-21. Amongst the carbon sources tested, glucose was the most effective for enzyme production and amongst the nitrogen sources tested, yeast extract was seen to be the most effective. A one percent addition of NaCl to the medium resulted in the highest fibrinolytic activity. Interestingly, a 10% addition of NaCl resulted in a high activity together with a high cell growth rate. Therefore, YJ11-21 is speculated of being a halotolerant. The optimum pH and temperature for enzyme production were a pH of 9.0 and $30^{circ}C$, respectively.
