Denitrovibrio acetiphilus, a novel genus and species of dissimilatory nitrate-reducing bacterium isolated from an oil reservoir model column

Abstract

A novel dissimilatory, nitrate-reducing bacterium, designated strain N2460T, was isolated from an oil reservoir model column. Strain N2460T is a mesophilic, obligately anaerobic, marine, gram-negative bacterium. The cells are vibrio-shaped and motile by a bipolar flagellum. Strain N2460T reduces nitrate to ammonia in a mineral medium supplied by acetate. The presence of a 2-oxoglutarate dehydrogenase activity indicates that acetate is oxidized via the citric acid cycle. No growth is obtained on formate, higher fatty acids, malate, fumarate, benzoate, alcohols, sugar, yeast extract, crude oil, alkanes, proline, hydrogen, sulfur or thiosulfate with nitrate as electron acceptor. Oxygen, sulfate, thiosulfate and sulfur are not utilized as alternative electron acceptors. Strain N2460T grows fermentatively on fumarate, but not on pyruvate. The G+C content of the DNA is 42.6 mol%. 16S rRNA gene analysis shows that strain N2460T belongs to the Bacteria and that the closest relative is 'Geovibrio ferrireducens' (sequence similarity 86.9%). On the basis of phylogenetic as well as phenotypic data, it is proposed that strain N2460T represents the type strain of a new genus and species, Denitrovibrio acetiphilus gen. nov., sp. nov.