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

Abstract

A novel moderately halophilic, sulfate-reducing bacterium, strain EtOH3T, 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 EtOH3T 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 MgCl2.6H2O l−1. The optimum NaCl concentration was 80–100 g l−1. Strain EtOH3T grew at temperatures ranging from 15 to 44 °C (optimum 37 °C). 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 (C1–5) alcohols, amino acids, H2/acetate and H2/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 EtOH3T within the deltaproteobacterial family Desulfohalobiaceae. Strain EtOH3T 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 5692T. High 16S rRNA gene sequence similarity (~97 %) was shared with the recently described strain ‘Desulfovermiculus halophilus’ VKM B-2364. Strain EtOH3T, 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 EtOH3T (=VKM B-2384T=DSM 17720T) as the type strain.