Cometabolism of the Superphylum <i>Patescibacteria</i> with Anammox Bacteria in a Long-Term Freshwater Anammox Column Reactor
Suguru Hosokawa,
Kyohei Kuroda,
Takashi Narihiro,
Yoshiteru Aoi,
Noriatsu Ozaki,
Akiyoshi Ohashi,
Tomonori Kindaichi
Affiliations
Suguru Hosokawa
Department of Civil and Environmental Engineering, Graduate School of Advanced Science and Engineering, Hiroshima University, 1-4-1 Kagamiyama, Higashihiroshima 739-8527, Japan
Kyohei Kuroda
Bioproduction Research Institute, National Institute of Advanced Industrial Science and Technology (AIST), 2-17-2-1 Tsukisamu-Higashi, Toyohira-ku, Sapporo, Hokkaido 062-8517, Japan
Takashi Narihiro
Bioproduction Research Institute, National Institute of Advanced Industrial Science and Technology (AIST), 2-17-2-1 Tsukisamu-Higashi, Toyohira-ku, Sapporo, Hokkaido 062-8517, Japan
Yoshiteru Aoi
Program of Biotechnology, Graduate School of Integrated Sciences for Life, Hiroshima University, 1-3-1 Kagamiyama, Higashihiroshima 739-8530, Japan
Noriatsu Ozaki
Department of Civil and Environmental Engineering, Graduate School of Advanced Science and Engineering, Hiroshima University, 1-4-1 Kagamiyama, Higashihiroshima 739-8527, Japan
Akiyoshi Ohashi
Department of Civil and Environmental Engineering, Graduate School of Advanced Science and Engineering, Hiroshima University, 1-4-1 Kagamiyama, Higashihiroshima 739-8527, Japan
Tomonori Kindaichi
Department of Civil and Environmental Engineering, Graduate School of Advanced Science and Engineering, Hiroshima University, 1-4-1 Kagamiyama, Higashihiroshima 739-8527, Japan
Although the anaerobic ammonium oxidation (anammox) process has attracted attention regarding its application in ammonia wastewater treatment based on its efficiency, the physiological characteristics of anammox bacteria remain unclear because of the lack of pure-culture representatives. The coexistence of heterotrophic bacteria has often been observed in anammox reactors, even in those fed with synthetic inorganic nutrient medium. In this study, we recovered 37 draft genome bins from a long-term-operated anammox column reactor and predicted the metabolic pathway of coexisting bacteria, especially Patescibacteria (also known as Candidate phyla radiation). Genes related to the nitrogen cycle were not detected in Patescibacterial bins, whereas nitrite, nitrate, and nitrous oxide-related genes were identified in most of the other bacteria. The pathway predicted for Patescibacteria suggests the lack of nitrogen marker genes and its ability to utilize poly-N-acetylglucosamine produced by dominant anammox bacteria. Coexisting Patescibacteria may play an ecological role in providing lactate and formate to other coexisting bacteria, supporting growth in the anammox reactor. Patescibacteria-centric coexisting bacteria, which produce anammox substrates and scavenge organic compounds produced within the anammox reactor, might be essential for the anammox ecosystem.
