RT Journal Article SR Electronic(1) A1 Boone, David R. A1 Mathrani, Indra M. A1 Liu, Yitai A1 Menaia, José A. G. F. A1 Mah, Robert A. A1 Boone, Jane E.YR 1993 T1 Isolation and Characterization of Methanohalophilus portucalensis sp. nov. and DNA Reassociation Study of the Genus Methanohalophilus JF International Journal of Systematic and Evolutionary Microbiology, VO 43 IS 3 SP 430 OP 437 DO https://doi.org/10.1099/00207713-43-3-430 PB Microbiology Society, SN 1466-5034, AB Abstract Six strains of coccoid, halophilic methanogens were isolated from various salinaria and natural hypersaline environments. These isolates (strains FDF-1T [T = type strain], FDF-2, SF-2, Ret-1, SD-1, and Cas-1) grew on media containing methanol and mono-, di-, and trimethylamines as catabolic substrates, but not on media containing dimethyl sulfide, methane thiol, H2, formate, or acetate; when cells were provided with H2 in addition to methanol or trimethylamine, they grew on the medium containing a methyl substrate but did not catabolize H2. All of the strains were capable of growth in mineral medium to which trimethylamine was added as a catabolic substrate, although some strains were greatly stimulated by biotin or p-aminobenzoate. DNA reassociation and denaturing electrophoresis of whole-cell proteins indicated that strains FDF-1T, FDF-2, SF-2, and Ret-1, together with previously described strains SF-1, Z-7302, Z-7401, Z-7404, and Z-7405, belong to a new taxon named Methanohalophilus portucalensis sp. nov; FDF-1 (= OCM 59) is the type strain. These strains grew fastest at temperatures near 40°C and, in medium containing 0.5 to 2.5 M NaCl, at pH values near 7. The two new strains excluded from the species on the basis of the results of phylogenetic tests, strains Cas-1 and SD-1, also differed from M. portucalensis in some minor physiological characteristics. Strain Cas-1 was less halophilic (fastest growth occurred in the presence of 0.5 to 1 M NaCl), and strain SD-1 was slightly alkaliphilic (fastest growth occurred at pH 7.8). The DNA reassociation study also showed that Methanohalophilus mahii SLPT exhibited 52% sequence similarity with Methanohalophilus halophilus Z-7982T, supporting the classification of these organisms as separate but closely related species., UL https://www.microbiologyresearch.org/content/journal/ijsem/10.1099/00207713-43-3-430