[Candidatus "Jettenia moscovienalis" sp. nov., a New Species of Bacteria Carrying out Anaerobic Ammonium Oxidation].

A new species of bacteria oxidizing ammonium with nitrite under anoxic conditions was isolated from the activated sludge of a semi-industrial bioreactor treating digested sludge of the Kuryanovo wastewater treatment plant (Moscow, Russia). Physiological, morphological, and molecular genetic characterization of the isolate was carried out. The cells were ovoid (∼0.5 × 0.8 μm), with the intracellular membrane structures characteristic of anammox bacteria (anammoxosome and paryphoplasm); unlike other anammox bacteria, it possessed extensive intracellular membrane structures located in layers parallel to the cytoplasmic membrane, but never close to the anammoxosome. The cells formed aggregates 5–28 μm in diameter and readily attached to solid surfaces. The cells were morphologically labile, easily plasmolyzed, and lost their content. Doubling time was 28 days, μmax = 0.025 day−1; optimal temperature and pH for growth were 20–45°C and 8.0, respectively. Phylogenetic analysis of the 16S rRNA gene sequences suggested its classification as a new species of the candidate genus Jettenia (order Planctomycetales). The name Candidatus “Jettenia moscovienalis” sp. nov. was proposed for the new bacterium.