| Abstract |
A novel strain of methanogenic archaea, designated MC-20(T), was isolated from the anoxic sediment of a subsurface lake in Movile Cave, Mangalia, Romania. Cells were non-motile, Gram-stain-negative rods 3.5-4.0 µm in length and 0.6-0.7 µm in width, and occurred either singly or in short chains. Strain MC-20(T) was able to utilize H2/CO2, formate, 2-propanol and 2-butanol as substrate, but not acetate, methanol, ethanol, dimethyl sulfide, monomethylamine, dimethylamine or trimethylamine. Neither trypticase peptone nor yeast extract was required for growth. The major membrane lipids of strain MC-20(T) were archaeol phosphatidylethanolamine and diglycosyl archaeol, while archaeol phosphatidylinositol and glycosyl archaeol were present only in minor amounts. Optimal growth was observed at 33 °C, pH 7.4 and 0.08 M NaCl. Based on phylogenetic analysis of 16S rRNA gene sequences, strain MC-20(T) was closely affiliated with Methanobacterium oryzae FPi(T) (similarity 97.1%) and Methanobacterium lacus 17A1(T) (97.0%). The G+C content of the genomic DNA was 33.0 mol%. Based on phenotypic and genotypic differences, strain MC-20(T) was assigned to a novel species of the genus Methanobacterium for which the name Methanobacterium movilense sp. nov. is proposed. The type strain is MC-20(T) ( = DSM 26032(T) = JCM 18470(T)).
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