Ferrovibrio denitrificans gen. nov., sp nov., a novel neutrophilic facultative anaerobic Fe(II)-oxidizing bacterium

A neutrophilic Fe(II)-oxidizing bacterium was isolated from the redox zone of a low-salinity spring in Krasnodar krai (Russia), at the FeSFe(OH)3 interface deposited at the sediment surface. The cells of strain Sp-1 were short, thin motile vibrioids with one polar flagellum dividing by binary fission. The optimal values and ranges for pH and temperature were pH 6.2 (5.58) and 35 degrees C (545 degrees C), respectively. The organism was a facultative anaerobe. Strain Sp-1 was capable of organotrophic, lithoheterotrophic and mixotrophic growth with Fe(II) as an electron donor. The denitrification chain was disrupted. Oxidation of Fe(II) was coupled to reduction of NO3 - to NO2 - or of N2O to N2, as well as under microaerobic conditions, with O2 as an electron acceptor. The DNA G+C content was 64.2mol%. According to the results of phylogenetic analysis, the strain was 10.612% remote from the closest relatives, members of the genera Sneathiella, Inquilinus, Oceanibaculum and Phaeospirillum within the Alphaproteobacteria. Based on its morphological, physiological and taxonomic characteristics, together with the results of phylogenetic analysis, strain Sp-1 is described as a member of a new genus Ferrovibrio gen. nov., with the type species Ferrovibrio denitrificans sp. nov. and the type strain Sp-1T (=LMG 25817T=VKM B-2673T).