Authors
Shi Chen, Lai Peng, Yifeng Xu, Shengjun Li, Linchuan Fang, Yiwen Liu, Yan Zhou, Bing-Jie Ni
Published in
Environmental science & technology. Jul 14, 2026. Epub Jul 14, 2026.
Abstract
Nitrous oxide (N2O) emissions linked to ammonia-oxidizing archaea (AOA) lack a process-resolved kinetic framework, limiting accurate source attribution in wastewater nitrification. A mechanistic model was developed for N2O production in AOA-dominated systems, explicitly resolving the archaeal N-nitrosation hybrid pathway and coupling nitrite generation by AOA to heterotrophic denitrification via intracellular carbon storage. The model was calibrated using dynamic batch experiments with an AOA-enriched culture across dissolved oxygen gradients (1.47-7.35 mg L-1) and independently validated against temporal profiles of nitrogen species and N2O. The rate constant for the archaeal hybrid N2O production was quantified as kAOA = 0.4966 m3g-1d-1, yet yielded only 0.032-0.085% of oxidized nitrogen as N2O. Simulations indicated that N2O in AOA systems originated predominantly (>96%) from heterotrophic denitrification, while the archaeal hybrid pathway remained low-yield and insensitive to dissolved oxygen. In contrast, canonical ammonia-oxidizing bacteria-mediated systems exhibited higher N2O yields (3.1-8.7% of oxidized nitrogen), which were strongly suppressed under elevated oxygen. By transforming the conceptual hybrid pathway into a predictive, process-resolved framework, this model provided a kinetic basis for moving N2O mitigation strategies beyond uniform oxygen control toward approaches that account for nitrifier identity.
PMID:
42444350
Bibliographic data and abstract were imported from PubMed on 14 Jul 2026.
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