Desulfohalobium utahense sp. nov., a moderately halophilic, sulfate-reducing bacterium isolated from Great Salt Lake

Abstract

A novel moderately halophilic, sulfate-reducing bacterium, strain EtOH3(T), was isolated from anoxic hypersaline (270 g NaCl l(-1)) sediment of the northern arm of the Great Salt Lake, Utah, USA. Cells of strain EtOH3(T) were oval to rod-shaped, non-motile, non-sporulating and stained Gram-negative. The strain required sodium and magnesium ions for growth and grew at salinities of up to 240 g NaCl l(-1) and 121 g MgCl(2).6H(2)O l(-1). The optimum NaCl concentration was 80-100 g l(-1). Strain EtOH3(T) grew at temperatures ranging from 15 to 44 degrees Celsius (optimum 37 degrees Celsius). The pH range for growth was 6.5-8.3 (optimum around pH 6.8). Only sulfate and thiosulfate served as electron acceptors for a broad range of electron donors including various short-chain fatty acids and primary (C(1-5)) alcohols, amino acids, H(2)/acetate and H(2)/yeast extract. The G+C content of the genomic DNA was 51.4 mol%. Phylogenetic analysis of dsrAB [genes encoding the major subunits of dissimilatory (bi)sulfite reductase] and 16S rRNA gene sequence data placed strain EtOH3(T) within the deltaproteobacterial family Desulfohalobiaceae. Strain EtOH3(T) shared 76 and 91 % dsrAB and 16S rRNA gene sequence similarity, respectively, with the type strain of the phylogenetically most closely related species with a validly published name, Desulfohalobium retbaense DSM 5692(T). High 16S rRNA gene sequence similarity ( approximately 97 %) was shared with the recently described strain 'Desulfovermiculus halophilus' VKM B-2364. Strain EtOH3(T), however, clearly differed from this strain in both genomic G+C content and in several of its phenotypic properties. On the basis of phenotypic and genotypic characteristics, the novel species Desulfohalobium utahense sp. nov. is proposed, with strain EtOH3(T) (=VKM B-2384(T)=DSM 17720(T)) as the type strain.