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Oshiki M, Morimoto E, Kobayashi K, Satoh H, Okabe S. Collaborative metabolisms of urea and cyanate degradation in marine anammox bacterial culture. ISME COMMUNICATIONS 2024; 4:ycad007. [PMID: 38304081 PMCID: PMC10833080 DOI: 10.1093/ismeco/ycad007] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Figures] [Subscribe] [Scholar Register] [Received: 11/27/2023] [Revised: 11/30/2023] [Accepted: 12/01/2023] [Indexed: 02/03/2024]
Abstract
Anammox process greatly contributes to nitrogen loss occurring in oceanic oxygen minimum zones (OMZs), where the availability of NH4+ is scarce as compared with NO2-. Remineralization of organic nitrogen compounds including urea and cyanate (OCN-) into NH4+ has been believed as an NH4+ source of the anammox process in oxygen minimum zones. However, urea- or OCN-- dependent anammox has not been well examined due to the lack of marine anammox bacterial culture. In the present study, urea and OCN- degradation in a marine anammox bacterial consortium were investigated based on 15N-tracer experiments and metagenomic analysis. Although a marine anammox bacterium, Candidatus Scalindua sp., itself was incapable of urea and OCN- degradation, urea was anoxically decomposed to NH4+ by the coexisting ureolytic bacteria (Rhizobiaceae, Nitrosomonadaceae, and/or Thalassopiraceae bacteria), whereas OCN- was abiotically degraded to NH4+. The produced NH4+ was subsequently utilized in the anammox process. The activity of the urea degradation increased under microaerobic condition (ca. 32-42 μM dissolved O2, DO), and the contribution of the anammox process to the total nitrogen loss also increased up to 33.3% at 32 μM DO. Urea-dependent anammox activities were further examined in a fluid thioglycolate media with a vertical gradient of O2 concentration, and the active collaborative metabolism of the urea degradation and anammox was detected at the lower oxycline (21 μM DO).
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Affiliation(s)
- Mamoru Oshiki
- Division of Environmental Engineering, Faculty of Engineering, Hokkaido University, North 13, West 8, Kita-ku, Sapporo, Hokkaido 060-8628, Japan
| | - Emi Morimoto
- Division of Environmental Engineering, Faculty of Engineering, Hokkaido University, North 13, West 8, Kita-ku, Sapporo, Hokkaido 060-8628, Japan
| | - Kanae Kobayashi
- Division of Environmental Engineering, Faculty of Engineering, Hokkaido University, North 13, West 8, Kita-ku, Sapporo, Hokkaido 060-8628, Japan
- Institute for Extra-Cutting-Edge Science and Technology Avant-Garde Research (X-star), Japan Agency for Marine-Earth Science and Technology (JAMSTEC), 2-15 Natsushima-cho, Yokosuka, Kanagawa 237-0061, Japan
| | - Hisashi Satoh
- Division of Environmental Engineering, Faculty of Engineering, Hokkaido University, North 13, West 8, Kita-ku, Sapporo, Hokkaido 060-8628, Japan
| | - Satoshi Okabe
- Division of Environmental Engineering, Faculty of Engineering, Hokkaido University, North 13, West 8, Kita-ku, Sapporo, Hokkaido 060-8628, Japan
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