PURPOSE: A compound with antibacterial activity isolated from Chunggukjang is provided to develop a drug as an antibacterial activity against Xanthomonas oryzae pv. oryzae. CONSTITUTION: An antibacterial composition contains a compound selected from chemical formulas 1-6 as an active ingredient. The compounds of chemical formulas 1-6 are glycitein, daidzein, acetylgenistin, genistein, surfactin A, and surfactin B, respectively. A method for preparing the compounds comprises: a step of fermenting Chunggukjang for 24-72 hours； and a step of isolating Chunggukjang using a solvent.본 발명은 적정한 발효를 수행한 발효 청국장으로부터 분리한 항균 활성을 지닌 화합물에 관한 것으로서, 더욱 상세하게는 청국장으로부터 2차 대사산물을 스크리닝하여 얻은 항균 활성을 가진 화합물 및 그 화합물의 항균 활성의 용도에 관한 것이다.
