Abstract
ML Fardeau, M Magot, BKC Patel, P Thomas, JL Garcia and B Ollivier
Laboratoire de Microbiologie IRD, Universites de Provence et de la Mediterranee, ESIL case 925, 163 Avenue de Luminy, 13288 Marseille cedex 9, France
A new thermophilic, anaerobic glucose-fermenting, Gram-positive, rod-shaped bacterium, designated strain SEBR 7858(T), was isolated from an oilfield water sample. Under optimal conditions on a glucose-containing medium (3% NaCl, 65 degrees C and pH 7.5), the generation time was 2.5 h. No growth occurred at 35 or 80 degrees C, nor at pH 5.5 or 9.0. Strain SEBR 7858(T) possessed lateral flagella. Spores were undetected but heat-resistant forms were present. Strain SEBR 7858(T) fermented a range of carbohydrates to acetate, L-alanine, lactate, H(2) and CO(2). The isolate reduced thiosulfate and elemental sulfur, but not sulfate or sulfite to sulfide. In the presence of thiosulfate, the ratio of acetate produced per mole of glucose consumed increased, suggesting a shift in the use of electron acceptors during carbohydrate metabolism. The DNA G+C content was 41 mol%. Based on 16S rRNA gene sequence analysis, the strain was almost equidistantly related to all members of the genus Thermoanaerobacter (mean similarity 92%). Based on phenotypic, genomic and phylogenetic characteristics, strain SEBR 7858(T) was clearly different from all members of the genus Thermoanaerobacter and was therefore designated as a new species, Thermoanaerobacter subterraneus sp. nov. The type strain is SEBR 7858(T)(=CNCM I-2383(T), DSM 13054(T)).