Characterization Of Desulfovibrio Salinus Sp Nov., A Slightly Halophilic Sulfate-Reducing Bacterium Isolated From A Saline Lake In Tunisia

A novel slightly halophilic sulfate-reducing bacterium, designated strain P1BSR(T), was isolated from water of a saline lake in Tunisia. Strain P1BSR(T) had motile (single polar flagellum), Gram-negative, rod-shaped, non-spore-forming cells, occurring singly or in pairs. Strain P1BSR(T) grew at temperatures between 15 and 45 degrees C (optimum 40 degrees C), and in a pH range between 6 and 8.5 (optimum pH 6.7). The strain required NaCl for growth (1 % w/v), and tolerated high NaCl concentration (up to 12 % w/v) with an optimum of 3 % (w/v). Sulfate, thiosulfate and sulfite served as terminal electron acceptors, but not elemental sulfur, fumarate, nitrate and nitrite. Strain P1BSR(T) utilized lactate, pyruvate, formate, D-fructose and glycerol as carbon and energy sources. The main cellular fatty acid was C-16:0 (50.8 %). The genomic DNA G+C content was 47.7 mol%. Phylogenetic analysis of 16S rRNA gene sequence similarity indicated that strain P1BSR(T) was affiliated to the genus Desulfovibrio, with the type strains Desulfovibrio salexigens (96.51 %), Desulfovibrio zosterae (95.68 %), Desulfovibrio hydrothermalis (94.81 %) and Desulfovibrio ferrireducens (94.73 %) as its closest phylogenetic relatives. On the basis of genotypic, phenotypic and phylogenetic characteristics, it is proposed to assign strain P1BSR(T) to a novel species of the genus Desulfovibrio, Desulfovibrio salinus sp. nov. The type strain is P1BSR(T) (=DSM 101510(T)=JCM 31065(T)).