Environmental Science & Technology, Journal Year: 2025, Volume and Issue: unknown

Published: April 6, 2025

Anammox is an energy-efficient nitrogen removal process in which anammox bacteria (AnAOB) oxidize NH4+-N to N2 using NO2--N as the electron acceptor. Recent evidence suggests that AnAOB can perform extracellular transfer (EET), potentially coupling Fe(III) reduction with oxidation (Feammox). However, whether directly participate Feammox within complex wastewater treatment systems remains unclear. Here, we investigated iron-mediated metabolism pathways a microaerobic granular sludge (MGS) reactor by integrating enzyme inhibition assays analyses of gene dynamics and co-occurrence patterns nitrogen- iron-cycling genes. Results demonstrate contributed activity. The iron CT573071, coding porin-cytochrome c protein associated EET, co-occurred hao, hzsABC, hdh genes Candidatus Kuenenia, suggesting its role Feammox. Furthermore, four high-quality metagenome-assembled genomes (MAGs) affiliated Kuenenia stuttgartiensis_A harbored hao-like, genes, along hao-cluster, catalyzes hydroxylamine. This genomic further supports their dual metabolic capacity. Metatranscriptomic analysis confirmed CT573071 upregulation coexpression These findings establish potential K. Feammox, providing novel insights into low-strength systems.

Language: Английский