Ancylobacter lacus sp. nov. and Ancylobacter plantiphilus sp. nov., Novel Aerobic Facultative Methylotrophic Bacteria

Abstract

Novel aerobic facultatively methylotrophic bacteria were isolated from the water of a freshwater lake (strain F30LT), soil sample of rhizosphere of white clover Trifolium repens L. (strain 1TCT), and rhizosphere of carrot Daucus carota L. (strain Dau2). The isolates were gram-negative, non-spore-forming, nonmotile, pleomorphic/rod-shaped cells, propagating by binary fission; they were facultative methylotrophs, using a broad range of polycarbon compounds, apart from methanol. Optimum growth occurred at 25−29 °C and pH 7.0‒7.5, 0.5 vol % СН3OH, and 0.05 wt % NaCl. The strains employ the ribulose bisphosphate pathway for C1 assimilation. The predominant phospholipids were phosphatidylcholine, phosphatidylethanolamine, phosphatidylglycerol, and diphosphatidylglycerol. In the whole-cell fatty acid pattern of strains, C18:1 ω7c, C19: 0 ω8c cyclo, C16:0 and С18:0 acids were predominant. The major ubiquinone was Q-10. According to the 16S rRNA gene sequencing, strain F30LT exhibited high similarity to Ancylobacter dichloromethanicus DM16T (97.8%), while strains 1ТСT and Dau2 were closely related to A. oerskovii DSM 18746T (98.6%). The 16S rRNA gene sequence similarity between strains 1TCT and Dau2 was 99.4%. DNA–DNA hybridization of the strain F30LT with A. dichloromethanicus DM16T revealed only 22% homology; homology for strain 1ТСT and A. oerskovii DSM 18746T was 27%, while DNA‒DNA homology between strains 1TCT and Dau2 was 77%. Based on the data obtained, strain F30LT was identified as a new species within the genus Ancylobacter, Ancylobacter lacus sp. nov. (VKM В-3280Т = DSM 106439T). Strains 1ТСТ and Dau2 (=ВКМ В-3227 = CCUG71988) represent a novel species of the same genus, for which the name Ancylobacterplantiphilus sp. nov. is proposed, with the type strain 1ТСТ (=VKM В-3219Т = DSM 106438T).