Halophilic and halotolerant aerobic methylobacteria from the technogenic Solikamsk biotopes

Seven strains of moderately halophilic and halotolerant aerobic methylobacteria from the technogenic Solikamsk biotopes (Perm krai, Russia) were isolated in pure cultures and characterized. The isolates were represented by gram-negative and gram-positive (strain 2395B) cells. All the cells were shown to multiply by binary fission without formation of spores or prosthecae. All isolates except strain 2395B were able to oxidize methanol by a classical methanol dehydrogenase. The ribulose monophosphate (RMP) (strain LS), serine (strains S12, S3, 2395A), or ribulose bisphosphate (strains SK15 and S3270) pathways of C₁-assimilation were used. In strain 2395B, the key enzymes of the RMP and serine metabolic pathways were determined. Using polyphasic taxonomy, three strains were identified as representatives of the known species: Arthrobacter protophormiae 2395B, Methylophaga thalassica LS, and Ancylobacter rudongensis S3270. Three more strains were identified as members of new species: Methylopila oligotropha sp. nov. (strain 2395AT; VKM B-2788^T = CCUG 63805^T), Ancylobacter defluvii sp. nov. (strain SK15^T; VKM B-2789^T = CCUG 63806^T), and Paracoccus communis sp. nov. (strain S3^T; VKM B-2787^T = CCUG 63804^T). According to the results of 16S rRNA gene sequencing, the obligately methylotrophic strain S12 had less than 94% similarity with the known genera of the Proteobacteria and was probably a representative of a novel genus.