Ardenticatena maritima gen. nov., sp. nov., a ferric iron- and nitrate-reducing bacterium of the phylum 'Chloroflexi' isolated from an iron-rich coastal hydrothermal field, and description of Ardenticatenia classis nov

A novel thermophilic, chemoheterotrophic, Gram-negative-staining, multicellular filamentous bacterium, designated strain 110S^T, was isolated from an iron-rich coastal hydrothermal field in Japan. The isolate is facultatively aerobic and chemoheterotrophic. Phylogenetic analysis using 16S rRNA gene sequences nested strain 110S^T in a novel class-level clone cluster of the phylum 'Chloroflexi'. The isolate grows by dissimilatory iron- and nitrate-reduction under anaerobic conditions, which is the first report of these abilities in the phylum 'Chloroflexi'. The organism is capable of growth with oxygen, ferric iron and nitrate as a possible electron acceptor, has a wide range of growth temperatures, and tolerates higher NaCl concentrations for growth compared to the other isolates in the phylum. Using phenotypic and phylogenetic data, strain 110S^T (= JCM 17282^T = NBRC 107679^T = DSM 23922^T = KCTC 23289^T = ATCC BAA-2145^T) is proposed as the type strain of a novel species in a new genus, Ardenticatena maritima gen. nov., sp. nov. In addition, as strain 110S^T apparently constitutes a new class of the phylum 'Chloroflexi' with other related uncultivated clone sequences, we propose Ardenticatenia classis nov. and the subordinate taxa Ardenticatenales ord. nov. and Ardenticatenaceae fam. nov.