Micropruina glycogenica gen. nov., sp. nov., a new Gram-positive glycogen-accumulating bacterium isolated from activated sludge

A new Gram-positive non-spore-forming bacterium, strain Lg2(T), was isolated from an activated sludge reactor showing enhanced biological phosphorus removal activity. The new isolate was a slowly growing organism and was capable of accumulating large amounts of intracellular glycogen from substrate taken up. Both oxidase and catalase were produced. The new isolate contained meso-diaminopimelic acid (DAP) in the cell wall. Complex fatty acid patterns with iso-C(14:0), anteiso-C(15:0), C(16:0), iso-C(16:0) and four other minor saturated or unsaturated straight-chain fatty acids were detected. The isolate contained a high genomic G+C content (70.5 mol%). Phylogenetic analysis based on the 16S rRNA gene sequence placed the isolate in the high G+C Gram-positive group with Microlunatus phosphovorus and Friedmanniella antarctica as the closest relatives (sequence similarities are 93 and 92%, respectively). These three organisms shared common features in morphology, but strain Lg2(T) could be differentiated from the other species by its peptidoglycan type (meso-DAP), fatty acid composition, carbon source utilization profile and G+C content. On the basis of these findings, it is proposed that a new genus and species, Micropruina glycogenica, should be created for the new isolate; the type strain is strain Lg2(T) (= JCM 10248(T)).