Hydrogenophaga electricum sp. nov., isolated from anodic biofilms of an acetate-fed microbial fuel cell.

A Gram-negative, non-spore-forming, rod-shaped bacterial strain, AR20(T), was isolated from anodic biofilms of an acetate-fed microbial fuel cell in Japan and subjected to a polyphasic taxonomic study. Strain AR20(T) grew optimally at pH 7.0-8.0 and 25°C. It contained Q-8 as the predominant ubiquinone and C16:0, summed feature 3 (C16:1ω7c and/or iso-C15:02OH), and C18:1ω7c as the major fatty acids. The DNA G+C content was 67.1 mol%. A neighbor-joining phylogenetic tree revealed that strain AR20(T) clustered with three type strains of the genus Hydrogenophaga (H. flava, H. bisanensis and H. pseudoflava). Strain AR20(T) exhibited 16S rRNA gene sequence similarity values of 95.8-97.7% to the type strains of the genus Hydrogenophaga. On the basis of phenotypic, chemotaxonomic and phylogenetic data, strain AR20(T) is considered a novel species of the genus Hydrogenophaga, for which the name Hydrogenophaga electricum sp. nov. is proposed. The type strain is AR20(T) (= KCTC 32195(T) = NBRC 109341(T)).