During attempts to obtain novel, human-associated species of the domain Archaea , a coccoid micro-organism, designated strain B10T, was isolated in pure culture from a sample of human faeces collected in Marseille, France. On the basis of its phenotypic characteristics and 16S rRNA and mcrA gene sequences, the novel strain was classified as a methanogenic archaeon. Cells of the strain were non-motile, Gram-staining-positive cocci that were approximately 850 nm in diameter and showed autofluorescence at 420 nm. Cells were lysed by 0.1 % (w/v) SDS. With hydrogen as the electron donor, strain B10T produced methane by reducing methanol. The novel strain was unable to produce methane when hydrogen or methanol was the sole energy source. In an atmosphere containing CO2, strain B10T could not produce methane from formate, acetate, trimethylamine, 2-butanol, 2-propanol, cyclopentanol, 2-pentanol, ethanol, 1-propanol or 2,3-butanediol. Strain B10T grew optimally with 0.5–1.0 % (w/v) NaCl, at pH 7.6 and at 37 °C. It required tungstate-selenite for growth. The complete genome of the novel strain was sequenced; the size of the genome was estimated to be 2.05 Mb and the genomic DNA G+C content was 59.93 mol%. In phylogenetic analyses based on 16S rRNA gene sequences, the highest sequence similarities (98.0–98.7 %) were seen between strain B10T and several uncultured, methanogenic Archaea that had been collected from the digestive tracts of a cockroach, a chicken and mammals. In the same analysis, the non-methanogenic ‘Candidatus Aciduliprofundum boonei’ DSM 19572 was identified as the cultured micro-organism that was most closely related to strain B10T (83.0 % 16S rRNA gene sequence similarity). Each of the three treeing algorithms used in the analysis of 16S rRNA gene sequences indicated that strain B10T belongs to a novel order that is distinct from the Thermoplasmatales . The novel strain also appeared to be distinct from Methanosphaera stadtmanae DSM 3091T (72.9 % 16S rRNA gene sequence similarity), another methanogenic archaeon that was isolated from human faeces and can use methanol in the presence of hydrogen. Based on the genetic and phenotypic evidence, strain B10T represents a novel species of a new genus for which the name Methanomassiliicoccus luminyensis gen. nov., sp. nov. is proposed. The type strain of the type species is B10T ( = DSM 24529T = CSUR P135T).
A novel pale pink-pigmented halophilic archaeon, strain DC30T, was isolated from Aran-Bidgol salt lake, a hypersaline playa in Iran. Cells of strain DC30T were non-motile and pleomorphic, from rods to triangular or disc-shaped. Strain DC30T required at least 1.7 M NaCl and 0.05 M MgCl2 for growth (optimum, 3 M NaCl and 0.1 M MgCl2). The optimum pH and temperature for growth of strain DC30T were pH 7.5 and 40 °C, respectively, although it was capable of growth over pH and temperature ranges of 6.5–8.5 and 25–50 °C, respectively. Analysis of the 16S rRNA gene sequence showed that strain DC30T was a member of the family Halobacteriaceae . However, it had low 16S rRNA gene sequence similarities of 92.4 %, 89.4 % and 89.1 % to the most closely related haloarchaeal taxa, the type species of the genera Halorubrum , Halogranum and Haloplanus , respectively. The DNA G+C content was 66.0 mol%. Phosphatidylglycerol and phosphatidylglycerol phosphate methyl ester, common phospholipids found in haloarchaea, were present. Three minor phospholipids and one unidentified glycolipid were also observed. The only quinone present was MK-8(II-H2). The physiological, biochemical and phylogenetic differences between strain DC30T and other previously described genera of extremely halophilic archaea suggest that strain DC30T represents a novel species in a new genus within the family Halobacteriaceae , for which the name Halopenitus persicus gen. nov., sp. nov. is proposed. The type strain of Halopenitus persicus is DC30T ( = IBRC 10041T = KCTC 4046T).