sp. nov., a methylotrophic nitrogen-fixing species isolated from raised bog.

Nitrogen-fixing bacterial strain, designated B2, was isolated from methane-oxidation enrichment originating from a -dominated raised peatland in Tver region, Russia, and its phenotypic, chemotaxonomic and genomic characteristics were investigated. Cells of isolate were Gram-negative, aerobic, rod or spiral-shaped, with motility provided by a single polar flagellum in liquid media and peritrichous flagella on solid media. Strain was able to grow at 15-40 °C, pH 5.5-8.5 and tolerated NaCl to 2.0 % (w/v). Strain B2 gave positive amplification for dinitrogen reductase ( gene) and acetylene reduction activity was recorded up to 1250 nmol ethylene h (mg protein). Analysis of 16S rRNA showed that B2 represents a member of the genus and had the highest sequence similarity with SgZ-5 (97.92 %). The predominant quinone system was ubiquinone Q-10 and the major fatty acids were Cω7, Cω7 and C. The strain was facultative methylotrophic and used methanol and formate for the growth. Genome sequencing revealed a genome size of 8.0 Mbp and a G+C content of 67.8 mol%. The aFI genes encoding methanol dehydrogenase were absent, but a homologous F gene was detected. The genes encoding enzymes involved in the biosynthesis of tetrahydromethanopterin (HMPT) (formaldehyde oxidation) and NAD-linked formate dehydrogenase () were identified. Pairwise determined whole genome average nucleotide identity (gANI) values confirmed that strain B2 represents a novel species, for which we propose the name sp. nov. with the type strain B2 (VKM B-3233, КСТС 62613).