| Abstract |
The taxonomic positions and phylogenetic relationships of two new methylotrophic isolates from Lake Washington (USA) sediment, FAM5T and 500, and the previously described methylotrophic strain EHg5 isolated from contaminated soil in Estarreja (Portugal) were investigated. All three strains were facultative methylotrophs capable of growth on a variety of C1 and multicarbon compounds. Optimal growth occurred at pH 7.5-8 and 30-37 degrees C. The major fatty acids were C16:1omega7c and C16:0. The major quinone was ubiquinone Q8. Neither methanol dehydrogenase nor methanol oxidase activities were detectable in cells grown on methanol, suggesting an alternative, as-yet unknown, mechanism for methanol oxidation. The isolates assimilated C1 units at the level of formaldehyde, via the serine cycle. The DNA G+C content of the strains ranged between 64 and 65 mol%. 16S rRNA gene sequence similarity between the three new isolates was 99.85-100%, but was below 94% with other members of the Betaproteobacteria, indicating that the isolates represent a novel taxon. Based on physiological, phenotypic and genomic characteristics of the three isolates, a new genus, Methyloversatilis gen. nov., is proposed within the family Rhodocyclaceae. The type strain of Methyloversatilis universalis gen. nov., sp. nov. is FAM5T (=CCUG 52030T=JCM 13912T).
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