DESULFOTOMACULUM THERMOCISTERNUM SP-NOV, A SULFATE REDUCER ISOLATED FROM A HOT NORTH-SEA-OIL RESERVOIR

The organism described in this paper, strain ST90(T) (T = type strain) , is a thermophilic, spore-forming, rod-shaped sulfate reducer that wa s isolated from North Sea oil reservoir formation water, In cultivatio n the following substances were used as electron donors and carbon sou rces: H-2-CO2, lactate, pyruvate, ethanol, propanol, butanol, and C-3 to C-10 and C-14 to C-17 carboxylic acids, Sulfate was used as the ele ctron acceptor in these reactions, Lactate was incompletely oxidized, Sulfite and thiosulfate were also used as electron accepters, In the a bsence of an electron acceptor, the organism grew syntrophically on pr opionate together with a hydrogenothrophic methanogen, The optimum con ditions for growth on lactate and sulfate were 62 degrees C, pH 6.7, a nd 50 to 200 mM NaCl, The G+C content was 56 mol%, as determined by hi gh-performance liquid chromatography and 57 mol% as determined by ther mal denaturation. Spore formation was observed when the organism was g rown on butyrate or propanol as a substrate and at low pH values, On t he basis of differences in G+C content and phenotypic and immunologica l characteristics when the organism was compared with other thermophil ic Desulfotomaculum species, we propose that strain ST90(T) is a membe r of a new species, Desulfotomaculum thermocisternum. D. thermocisteun um can be quickly identified and distinguished from closely related De sulfotomaculum species by immunoblotting.