Halobacteriumrubrum sp. nov., isolated from a marine solar saltern

Halophilic archaeal strain TGN-42-S1T was isolated from the Tanggu marine solar saltern, China. Cells from strain TGN-42-S1T were observed to be pleomorphic rods, stained Gram-negative, and formed red-pigmented colonies on solid media. Strain TGN-42-S1T was found to be able to grow at 20–50 °C (optimum 35–37 °C), at 1.7–4.8 M NaCl (optimum 3.1 M), at 0–1.0 M MgCl2 (optimum 0.1 M), and at pH 5.0–9.0 (optimum pH 7.0–7.5). The cells lysed in distilled water, and the minimal NaCl concentration to prevent cell-lysis was found to be 10 % (w/v). The major polar lipids of the strain were phosphatidic acid, phosphatidylglycerol, phosphatidylglycerol phosphate methyl ester, phosphatidylglycerol sulfate, galactosyl mannosyl glucosyl diether (TGD-1), sulfated galactosyl mannosyl glucosyl diether (S-TGD-1), sulfated galactosyl mannosyl galactofuranosyl glucosyl diether (S-TeGD), and three unidentified glycolipids which were chromatographically identical to those of the Halobacterium species. The 16S rRNA gene and rpoB′ gene of strain TGN-42-S1T were phylogenetically related to the corresponding genes of Halobacteriumjilantaiense CGMCC 1.5337T (98.8 and 93.5 % nucleotide identity, respectively), Halobacteriumsalinarum CGMCC 1.1958T (98.4 and 91.9 %), and Halobacteriumnoricense JCM 15102T (96.9 and 91.1 %). The DNA G + C content of strain TGN-42-S1T was determined to be 69.2 mol %. Strain TGN-42-S1T showed low DNA–DNA relatedness with Hbt. jilantaiense CGMCC 1.5337T and Hbt. salinarum CGMCC 1.1958T, the most closely related members of the genus Halobacterium. The phenotypic, chemotaxonomic, and phylogenetic properties suggested that strain TGN-42-S1T (=CGMCC 1.12575T =JCM 19908T) represents a new species of Halobacterium, for which the name Halobacteriumrubrum sp. nov. is proposed.