A new species is proposed for two facultatively methanotrophic representatives of the genus Methylocystis, strains H2sT and S284, which were isolated from an acidic (pH 4.3) Sphagnum peat bog lake (Teufelssee, Germany) and an acidic (pH 3.8) peat bog (European North Russia), respectively. Cells of strains H2sT and S284 are aerobic, Gram-negative, non-motile, curved coccoids or short rods that contain an intracytoplasmic membrane system typical of type II methanotrophs. They possess both a soluble and a particulate methane monooxygenase (MMO); the latter is represented by two isozymes, pMMO1 and pMMO2. The preferred growth substrates are methane and methanol. In the absence of C1 substrates, however, these methanotrophs are capable of slow growth on acetate. Atmospheric nitrogen is fixed by means of an aero-tolerant nitrogenase. Strains H2sT and S284 develop between pH 4.2 and 7.6 (optimum pH 6.0-6.5), and at temperatures between 8 and 37°C (optimum 25-30°C). The major fatty acids are C18:1w8c, C18:1w7c, and C16:1w7c; the major quinone is Q-8. The DNA G+C content is 62.0-62.3 mol%. Strains H2sT and S284 share identical 16S rRNA gene sequences, which displayed 96.6-97.3% similarity to sequences of other taxonomically characterized members of the genus Methylocystis. Therefore, strains H2sT and S284 are classified as a novel species, for which the name Methylocystis bryophila sp. nov. is proposed. Strain H2sT (=DSM 21852T = VKM B-2545T) is the type strain of Methylocystis bryophila.
|Journal||International Journal of Systematic and Evolutionary Microbiology|
|Publication status||Published - 2013|