토마토시들음병 방제균주인 Bacillus thuringiensis BK4의 항진균성 항생물질의 대량생산조건을 확립하였고, 항생물질 BK4를 조정제 수준에서 in vitro, in vivo pot 실험을 통해 실제 토마토 시들음병에 대한 토양내 방제력을 검증하였다. B. thuringiensis BK4는 탄소원으로 0.5% xylose, 질소원으로 0.2% peptone No. 3, 5 mM $CaCl_2$를 첨가하였을 때 토마토 시들음병균인 Fusarium oxysoporum에 대한 항진균활성과 균체생산량이 가장 높았으며 또한, B. thuringiensis BK4가 생산하는 항진균성 항생물질 BK4를 조정제 수준에서 in vivo pot 실험을 통해 토마토 시들음병균인 F. oxysoporum에 대한 방제력이 탁월하다는 것을 확인하였다. B. thuringiensis BK4의 균체와 조정제수준의 항생물질 BK4를 병용처리 하였을 경우 각각을 단독으로 처리하였을 때와 비교하여 상가(相加)효과를 확인할 수 있었으며, 기대했던 상승(相乘)효과는 확인하지 못하였다. B. thuringiensis BK4가 생산하는 항생물질 BK4를 Sephadex LH-20 column chromatography와 prep-HPLC를 통해 retention time이 38min인 단일물질로 정제할 수 있었으며, 정제된 항생물질의 MIC(Minimum Inhibition Concentration)를 측정한 결과 50${mu}$g/ml이었다.
The optimum production condition for the antibiotic from Bacillus thuringiensis BK4 was determined, and the suppression rate of Fusarium-wilt by the butanol-extracted antibiotic was verified by employing tomatoes in vitro and in vivo pot tests. Cell growth and antifungal activity were the best when 0.5% xylose and 0.2% peptone No.3 were given as carbon and nitrogen sources, respectively, in the presence of 5mM $CaCl_2$. The partially purified antibiotic successfully prevented Fusarium oxysporum pathogen in pot experiments. When the pots were treated with both live cells and the partially purified antibiotic, an additive-effect was seen in the suppression of Fusarium-wilt, but synergistic effect was not detected. The antibiotic, denoted BK4, purified by Sephadex LH-20 column chromatography was eluted with a single peak at a retention time of 38 min. on prep-HPLC; Minimum inhibition concentration of the homogenous antibiotic was determined to be 50${mu}$g/ml.
