An extremely halophilic archaeon belonging to the genus Halorubrum , strain C49T, was isolated from sediment of the hypersaline lake Aran-Bidgol in Iran. Phylogenetic analysis based on 16S rRNA gene sequence similarities showed that strain C49T was closely related to Halorubrum saccharovorum JCM 8865T (99.5 %) and other species of the genus Halorubrum . Studies based on multilocus sequence analysis revealed that strain C49T is placed among the species of Halorubrum ; the strain constituted a defined branch in comparison with the type strains of species of Halorubrum , while the 16S rRNA gene sequence divergence could not define the status of the newly isolated strain. For optimum growth, strain C49T required 20 % (w/v) salts at pH 7.0 and 37 °C under aerobic conditions. Mg2+ was not required. The cells were pleomorphic rods, motile and stained Gram-variable. Colonies of the strain were pink. Hypotonic treatment with <12 % NaCl provoked cell lysis. The polar lipid pattern of strain C49T consisted of phosphatidylglycerol, phosphatidylglycerol phosphate methyl ester derived from both C20C20 and C20C25 archaeol, phosphatidylglycerol sulfate and sulfated mannosyl glucosyl diether. The DNA G+C content was 64.2 mol%. DNA–DNA hybridization studies and average nucleotide identity confirmed that strain C49T constitutes a distinct genospecies. Data obtained in this study show that strain C49T represents a novel species, for which the name Halorubrum persicum sp. nov. is proposed. The type strain is C49T ( = IBRC-M 10232T = JCM 30541T).
A novel, strictly anaerobic, hydrogenotrophic methanogen, strain E09F.3T, was isolated from a commercial biogas plant in Germany. Cells of E09F.3T were Gram-stain-negative, non-motile, slightly curved rods, long chains of which formed large aggregates consisting of intertwined bundles of chains. Cells utilized H2+CO2 and, to a lesser extent, formate as substrates for growth and methanogenesis. The optimal growth temperature was around 40 °C; maximum growth rate was obtained at pH around 7.0 with approximately 6.8 mM NaCl. The DNA G+C content of strain E09F.3T was 39.1 mol%. Phylogenetic analyses based on 16S rRNA and mcrA gene sequences placed strain E09F.3T within the genus Methanobacterium. On the basis of 16S rRNA gene sequence similarity, strain E09F.3T was closely related to Methanobacterium congolense CT but morphological, physiological and genomic characteristics indicated that strain E09F.3T represents a novel species. The name Methanobacterium aggregans sp. nov. is proposed for this novel species, with strain E09F.3T ( = DSM 29428T = JCM 30569T) as the type strain.