Petrotoga halophila sp. nov., a thermophilic, moderately halophilic, fermentative bacterium isolated from an offshore oil well in Congo
Résumé
A novel thermophilic, moderately halophilic, rod-shaped bacterium, strain MET-B T , with a sheath-like outer structure (toga) was isolated from an offshore oil-producing well in Congo, West Africa. Strain MET-B T was a Gram-negative bacterium with the ability to reduce elemental sulfur, but not sulfate, thiosulfate or sulfite into sulfide. The optimum growth conditions were 60 °C, pH 6.7–7.2 and 4–6 % NaCl. The DNA G+C content was 34.6 mol%. Strain MET-B T was phylogenetically related to members of the genus Petrotoga ; Petrotoga miotherma , Petrotoga olearia and Petrotoga mexicana were the closest relatives, with type strains exhibiting more than 99 % identity in an analysis of small-subunit rRNA gene sequences. The values for DNA–DNA relatedness between the type strains of these three species and strain MET-B T were less than 42 %. As MET-B T was found to be genetically and physiologically different from other species of the genus Petrotoga , this strain is proposed as representing a novel species, for which the name Petrotoga halophila sp. nov. is proposed. The type strain is MET-B T (=DSM 16923 T =CCUG 50214 T ).