Description of “Candidatus Jettenia ecosi” sp. nov., a New Species of Anammox Bacteria

— A new species of anammox bacteria, “ Candidatus Jettenia ecosi,” was identified in the microbial community of a lab-scale vertical anaerobic upflow bioreactor fed with mineral medium and the biomass immobilized on a brush-shaped carrier. The reactor was inoculated with activated sludge from a denitrifying bioreactor of a municipal wastewater treatment station in the valley of the Mzymta River (Krasnodar krai, Russia). At constant increase of concentrations of the substrates for the anammox process ( and ) in the course of five years, a microbial community containing a new species of anammox bacteria “ Candidatus Jettenia ecosi” developed in the bioreactor. Stable activity in a wide range of substrate concentrations (0.02 to 5.6 g N/L), рН (7.2 to 8.8), and under microaerophilic conditions (3% oxygen in the gas phase) were the remarkable features of the new species. Optimal growth temperature was 30°C. Doubling time of physiologically active anammox bacteria was 13 days. Cells of the new bacteria (~1 µm in diameter) exhibited the typical anammox morphology and ultrastructure. The cells had a tendency for attached growth and formation of biofilms. Hopanoids and ladderane lipids, which are among the key markers of this microorganisms, were found in the membranes of the new anammox bacteria. According to the results of the 16S rRNA gene sequencing, the new bacteria belong to the candidate genus “ Candidatus Jettenia,” phylum Planctomycetes with the proposed name “ Candidatus Jettenia ecosi” sp. nov.