부영양화 해역에서 분리된 Vibrio sp. S-1-2균의 특성과 Cd축적에 관한 연구

Studies on Bacterial Characteristics and Cd Accumulation of Vibrio sp. S-1-2, Isolated from Eutrophic Coastal Area

부영양화된 해역인 마산만에서 분리된 해양세균중 카드뮴 200ppm에서 내성을 보인 균을 분리배양하고, 미생물학적 성질과 생체 축적량을 방사성 동위원소인 $^{109}CdC_2$을 이용하여 측정한 결과는 다음과 같다. 1. 분리된 카드뮴 내성균은 Gram음성균이며 단간균으로서 운동성이 있고 생리, 생화학 특성과 TCBS 배지에서의 집락 형태로 보아 Vibrio sp.으로밝혀졌다. 2. 본 균의 다른 중금속에 대한 내성 실험에서 $ZnCl_2$, $PbCl_2$, $CuCl_2$가 25ppm 함유된 배지에서는 서로 비슷한 성장을 보였지만 $HgCl_2$ 25ppm에서는 성장이 거의 안되었다. 3. 균체내의 카드뮴 축적량은 배지에 포함된 카드뮴의 양과 비례하여 증가하여 75ppm에서 43.2mg/l로 최고의 축적을 나타내었고, 100ppm에서의 성장이 저해되었지만 균체 축적량이 일정하게 유지되었다. 4. 방사성 동위원소인 $ ^{109}CdCl_2$를 이용하여 25ppm에서 배양한 후, 중금속 축적조건을 dpm값을 통해 조사한 결과는 96시간 배양시 pH 7에 최대값인 $2554{\times}10^4dpm/m{\ell}$을 나타냈고, NaCl에서는 36시간 배양시 $611{\times}10^4dpm/m{\ell}$로 최고값을 나타내었다.

Vibrio sp. S-1-2 was isolated from seawater in the Masan bay and its bacterial characteristics and bioaccumulation of $CdCl_2$ in the cell were investigated. As the result of microscopic and biochemical test, the S-1-2 strain was identified to Vibrio sp. and this strain can be tolerated even in 200 ppm $CdCl_2$ media, however its growth was inhibited. In 25 ppm $ZnCl_2$ media, the growth of Cd resistant Vibrio sp. S-1-2 was promoted at later stage of growth. The growth of Vibrio sp. S-1-2 was inhibited on 25 ppm $CuCl_2$ and $PbCl_2$ media and was not able to grow in 25 ppm $HgCl_2$ media at all. The uptake of cadium in the cells was increased exponentially with increasing concentration of $CdCl_2$ in media. But the uptake rate of cadmium was suddenly inhibited at 50 ppm $CdCl_2$ media. Optimal pH and NaCl concentration for bioaccumulation of $CdCl_2$ were 8-9 and 1-2%, respectively. In the case of pH, maximum dpm value was found at pH 7 after 96 hours culture and in the case of NaCl concentration, it was detected in 2% NaCl media after 36 hours culture.