Halolamina salifodinae sp. nov. and Halolamina salina sp. nov., two extremely halophilic archaea isolated from a salt mine.

Two strictly aerobic, extremely halophilic archaea, strains WSY15-H1(T) and WSY15-H3(T), were isolated from a salt mine in Wensu county, Xinjiang province, China. Cells of the two strains were Gram-stain-negative, non-motile and pleomorphic. Colonies were pink- and red-pigmented, respectively. Strain WSY15-H1(T) grew at 20-45 °C (optimum 37-42 °C), 1.6-5.4 M NaCl (optimum 3.4-3.9 M), 0-2.0 M MgCl2 (optimum 0.1-0.5 M) and pH 6.0-9.0 (optimum 7.0), whereas strain WSY15-H3(T) grew at 20-50 °C (optimum 37 °C), 1.9-5.4 M NaCl (optimum 3.4 M), 0.02-2.5 M MgCl2 (optimum 0.5-1.0 M) and pH 6.0-7.5 (optimum 6.5). The minimal NaCl concentrations to prevent cell lysis were 9 % (w/v) for strain WSY15-H1(T) and 8 % (w/v) for strain WSY15-H3(T). The major polar lipids of the two isolates were phosphatidylglycerol, phosphatidylglycerol phosphate methyl ester and phosphatidylglycerol sulfate, as well as nine glycolipids for strain WSY15-H1(T) and seven glycolipids for strain WSY15-H3(T); two of these glycolipids (GL1 and GL3) were chromatographically identical to bis-sulfated diglycosyl diether (S2-DGD-1) and sulfated diglycosyl diether (S-DGD-1), respectively. The genomic DNA G+C contents of strains WSY15-H1(T) and WSY15-H3(T) were 65.4 and 66.2 mol%. On the basis of 16S rRNA gene sequence analysis, strains WSY15-H1(T) and WSY15-H3(T) shared 97.0% similarity with each other and showed respectively 98.4 and 97.6% sequence similarity to Halolamina pelagica TBN21(T), which was the only type strain that had higher than 91% sequence similarity with the two isolates. Analysis of phylogenetic relationships and DNA-DNA relatedness indicated that strains WSY15-H1(T) and WSY15-H3(T) represent two novel lineages with closest affinity to H. pelagica TBN21(T). Based on phenotypic, chemotaxonomic and genotypic characteristics, two novel species of the genus Halolamina are proposed, Halolamina salifodinae sp. nov. (type strain WSY15-H1(T) = JCM 18548(T) = GCMCC 1.12371(T)) and Halolamina salina sp. nov. (type strain WSY15-H3(T) = JCM 18549(T) = GCMCC 1.12285(T)).