Abstract
A thermophilic, anaerobic, spore-forming bacterium (strain Z-9801(T)) was isolated from a terrestrial hydrothermal source in the Uzon caldera on the Kamchatka peninsula. Cells of strain Z-9801(T) were straight, sometimes branched rods, 0.5--0.6 microm in diameter and 1.5--7.0 microm in length, with peritrichous flagella. The temperature range for growth was 45--76 degrees C, with an optimum at 63--65 degrees C. The pH range for growth was 4.8--8.2, with an optimum at 6.7--6.9. The substrates utilized by strain Z-9801(T) included peptone, yeast extract, beef extract, Casamino acids, starch, pyruvate, melibiose, sucrose, fructose, maltose, xylose and ribose. The fermentation products from melibiose were ethanol, acetate, H(2) and CO(2). Strain Z-9801(T) used H(2) in the presence of Fe(III) and an organic electron donor. Strain Z-9801(T) reduced Fe(III), Mn(IV), nitrate, fumarate, sulfite, thiosulfate, elemental sulfur and 9,10-anthraquinone 2,6-disulfonate. The G+C content of strain Z-9801(T) DNA was 36 mol%. 16S rDNA sequence analysis revealed that the isolated organism forms a separate branch within the Bacillus/Clostridium group. On the basis of physiological properties and phylogenetic analysis, it is proposed that strain Z-9801(T) (=DSM 14006(T)=UNIQEM 210(T)) should be assigned to a novel species of a new genus, Thermovenabulum ferriorganovorum gen. nov., sp. nov.