Desulfovibrio bastinii sp. nov. and Desulfovibrio gracilis sp. nov., moderately halophilic, sulfate-reducing bacteria isolated from deep subsurface oilfield water

1 Université de Pau et des Pays de l'Adour, IBEAS, Laboratoire d'Ecologie Moléculaire, EA3525, F-64013 Pau, France 2 11 Place Garibaldi, F-42000 Saint Etienne, France Correspondence Michel Magot michel.magot{at}univ-pau.fr Two moderately halophilic, mesophilic, sulfate-reducing bacteria were isolated from production-water samples from Emeraude Oilfield, Congo. Motile, vibrioid cells of SRL4225 T grew optimally at a concentration of 4 % NaCl, at pH 5·8–6·2, with a minimal pH for growth of 5·2, showing that it is a moderately acidophilic bacterium. Cells of SRL6146 T were motile, curved or vibrioid, long and thin rods. Optimal growth was obtained at a concentration of 5–6 % NaCl, at pH 6·8–7·2. The nutritional requirements showed that many of the characteristics of these strains overlap with those of known Desulfovibrio species. On the basis of 16S rRNA gene sequence analysis and DNA–DNA hybridization studies, both strains are members of the genus Desulfovibrio . However, they are not closely related to any species of the genus that have validly published names. It is therefore proposed that the two strains are members of two novel species of the genus Desulfovibrio with the names Desulfovibrio bastinii sp. nov. (type strain SRL4225 T =DSM 16055 T =ATCC BAA-903 T ) and Desulfovibrio gracilis sp. nov. (type strain SRL6146 T =DSM 16080 T =ATCC BAA-904 T ). Published online ahead of print on 26 March 2004 as DOI 10.1099/ijs.0.02977-0. The GenBank/EMBL/DDBJ accession numbers for the 16S rRNA gene sequences of SRL4225 T , SRL6146 T and Desulfovibrio longus DSM 6739 T are AY359868 , U53464 and AY359867 , respectively.