Isolation and Characterization of a New Hydrogen Sulfide-Oxidizing Bacterium Thiobacillus Sp.

황화수소 산화세균인 새로운 Thiobacillus sp.의 분리 및 특성

A new hydrogen sulfide-oxidation bacterium, Thiobacillus sp. was isolated from waste coal mine water around Hawsun in Chunnam province. The isolate was motile gram-negative rod shape, formed spore and grew up to be aerobically facultative chemolithotroph by using energy released from the oxidation of reduced inorganic sulfur compounds. It could assimilate various kinds of organic compounds and grew well upon thiosulfate-supplemented basal medium. To the lelvel of 32 mM in thiosulfate concentration, thiosulfate in itself was utilized as energy source for growth. However, from those of the higher concentration than 32 mM, thiosulfate functioned specifically as the substrate inhibitor rather than as the energy source. It was found that the optimum thiosulfate concentration for growth was 32 mM. The G+C content of the DNA was 65.0 mol%. The isolate had 16 : 1 + 17$_{cyc}$, 16 : 0 as their major non-hydroxylated cellular fatty acids, 3-OH 12 : 0 as a hydroxylated fatty acid and also contained unidentified $C_{18}$ branched fatty acid. The ubiquinone system in the respiratory chain was Q-9. Based on the physiological and biochemical characteristics, the isolate was assigned to a novel species of the genus Thiobacillus sp. iw.

황화수소 산화세균인 Thiobacillus sp.를 전남 화순의 폐탄광수에서 분리하였다. 분리된 균주는 그람음성의 운동성이 있고, 포자를 형성하는 간균이었으며, 환원된 무기 황화합물을 산화하여 에너지원으로 사용하는 호기성 통성 화학합성 영양균이었다. 분리균주는 thiosulfate를 첨가한 기본배지에서 유기물을 동화하며 성장하였고, 에너지원으로 사용된 thiosulfate는 32mM 이상의 농도에서는 오히려 기질억제 인자로 작용하여 균의 성장을 억제하였다. 최적 thiosulfate 농도는 32mM이었다. DNA의 G+C 함량은 65.0mol%이고, 세포내 주요 지방산중 비순산화 지방산은 16:1+7$_{cyc}$, 16:0과 수산화 지방산은 3-OH 12:0을 가지며, $C_{18}$의 미동정 가지형의 지방산도 포함하고 있었다. Ubiquinone system은 Q-9을 가지고 있었다. 위와 같은 생리생화학적 특성 결과로부터, 본 분리균주는 Thiobacillus sp. iw.의 새로운 종으로 판단하였다.