Tepidiphilus margaritifer gen. nov., sp. nov., isolated from a thermophilic aerobic digester

Abstract

A moderately thermophilic bacterium is described, strain N2-214T, that was isolated from an enrichment culture, growing on caprolactone, obtained from a sample from a water-treatment sludge aerobic digester operating at temperatures around 60 °C. The organism was aerobic, Gram-negative, oxidase- and catalase-positive, with a polar flagellum, and capable of growth at temperatures as high as 61 °C. The major fatty acids of strain N2-214T were C16 : 0, C18 : 1 and cyclo-C19 : 0. The phylogenetic relationships of the strain, derived from 16S rRNA gene sequence comparisons, demonstrated it to be a member of the {beta}-subclass of the Proteobacteria. The highest 16S rDNA sequence similarity of isolate N2-214T was to Azoarcus buckelii (91·9 %), Thauera aromatica (92 %) and Hydrogenophilus thermoluteolus (92·7 %). On the basis of phylogenetic analyses and physiological and chemotaxonomic characteristics, it is proposed that isolate N2-214T (=DSM 15129T=LMG 21637T) represents a new genus and species, Tepidiphilus margaritifer gen. nov., sp. nov.