Two halophilic archaea, strains EN-2T and SH-4, were isolated from the saline lakes Erliannor and Shangmatala, respectively, in Inner Mongolia, China. Cells were strictly aerobic, motile rods. Colonies were red. Strains EN-2T and SH-4 were able to grow at 25–50 °C (optimum 35–40 °C), with 2.5–5.0 M NaCl (optimum 3.4 M NaCl) and at pH 6.0–9.0 (optimum pH 7.5). MgCl2 was not required for growth. Cells lysed in distilled water and the lowest NaCl concentration that prevented cell lysis was 12 % (w/v). On the basis of 16S rRNA gene sequence analysis, strains EN-2T and SH-4 were closely related to Halorubrum cibi B31T (97.9 and 98.0 % similarity, respectively), Hrr. tibetense 8W8T (97.3 and 97.7 %), Hrr. alkaliphilum DZ-1T (96.8 and 97.1 %), Hrr. luteum CGSA15T (96.8 and 97.0 %) and Hrr. lipolyticum 9-3T (96.8 and 97.0 %). DNA–DNA hybridization showed that strains EN-2T and SH-4 did not belong to the same species as any of these strains (≤45 % DNA–DNA relatedness) but that they are members of the same species (>70 % DNA–DNA relatedness). Polar lipid analysis revealed that strains EN-2T and SH-4 contained phosphatidylglycerol, phosphatidylglycerol phosphate methyl ester, sulfated diglycosyl diethers and several unidentified glycolipids. The DNA G+C content of both isolates was 62.1 mol%. It was concluded that strains EN-2T and SH-4 represent a novel species of the genus Halorubrum, for which the name Halorubrum aquaticum sp. nov. is proposed. The type strain is EN-2T ( = CECT 7174T = CGMCC 1.6377T = JCM 14031T).
A Gram-negative, pleomorphic, aerobic, haloalkaliphilic archaeon, strain 167-74T, was isolated from commercial rock salt imported into Japan from China. Phylogenetic analysis based on 16S rRNA gene sequence similarities showed that strain 167-74T is closely related to Halostagnicola larsenii XH-48T (98.3 %) and Halostagnicola kamekurae 194-10T (97.2 %). The major polar lipids of the isolate were C20C20 and C20C25 derivatives of phosphatidylglycerol and phosphatidylglycerol phosphate methyl ester. A glycolipid was not detected, in contrast to the two existing, neutrophilic species of the genus Halostagnicola. The DNA G+C content of strain 167-74T was 60.7 mol%. and it gave DNA–DNA reassociation values of 19.5 and 18.8 %, respectively, with Hst. larsenii JCM 13463T and Hst. kamekurae 194-10T. Therefore, strain 167-74T represents a novel species, for which the name Halostagnicola alkaliphila sp. nov. is proposed, with the type strain 167-74T ( = JCM 16592T = CECT 7631T).