Wastewater-Derived Comammox Nitrospira for Next-Generation Wastewater Management.

The discovery of complete ammonia-oxidizing (comammox) Nitrospira in 2015 marked a major advance in our understanding of the nitrogen cycle and demonstrated that a single microorganism can catalyze the full oxidation of ammonia to nitrate, challenging the long-standing paradigm that separates ammonia- and nitrite-oxidizing microorganisms. Over the past decade, research on comammox has progressed rapidly from genomic discovery to detailed characterization of its physiology, kinetics, and ecological distribution across natural and engineered ecosystems. Wastewater-derived comammox Nitrospira have emerged as influential players in biological nitrogen transformations due to their exceptionally high substrate affinities, metabolic versatility, potentially low nitrous oxide emissions, and resilience under resource-limited conditions. These traits position comammox as promising catalysts for low-energy and sustainable nitrogen management in engineered systems. This review synthesizes the first decade of research on comammox Nitrospira, with a particular focus on wastewater-associated lineages. We examine the ecological niches that enable comammox Nitrospira to thrive in wastewater environments and analyze their competitive and cooperative interactions with canonical ammonia- and nitrite-oxidizing microorganisms. Building on these ecological insights, we discuss emerging comammox-centered biotechnological strategies for next-generation wastewater treatment and resource recovery. By linking microbial ecology with process engineering, this review highlights the potential for comammox-driven innovations to advance circular and energy-efficient nitrogen management in the coming decade.