Novel insight into the inhibitory effects and mechanisms of Fe(II)-mediated multi-metabolism in anaerobic ammonium oxidation (anammox)

Yushi Jiang; Yuqi Chen; Ying Wang; Xueming Chen; Xuanfan Zhou; Kexin Qing; Wenzhi Cao; Yanlong Zhang

doi:10.1016/j.watres.2023.120291

Novel insight into the inhibitory effects and mechanisms of Fe(II)-mediated multi-metabolism in anaerobic ammonium oxidation (anammox)

Water Res. 2023 Aug 15:242:120291. doi: 10.1016/j.watres.2023.120291. Epub 2023 Jun 29.

Authors

Yushi Jiang¹, Yuqi Chen¹, Ying Wang¹, Xueming Chen², Xuanfan Zhou¹, Kexin Qing¹, Wenzhi Cao¹, Yanlong Zhang³

Affiliations

¹ Key Laboratory of the Ministry of Education for Coastal and Wetland Ecosystem, College of the Environment & Ecology, Xiamen University, Xiamen, Fujian Province, 361102, China.
² Fujian Provincial Engineering Research Center of Rural Waste Recycling Technology, College of Environment and Safety Engineering, Fuzhou University, Fuzhou 350116, China.
³ Key Laboratory of the Ministry of Education for Coastal and Wetland Ecosystem, College of the Environment & Ecology, Xiamen University, Xiamen, Fujian Province, 361102, China; Fujian Key Laboratory of Coastal Pollution Prevention and Control (CPPC), College of Environment and Ecology, Xiamen University, Xiamen, Fujian Province, 361102, China. Electronic address: ylzhang@xmu.edu.cn.

PMID: 37413747
DOI: 10.1016/j.watres.2023.120291

Abstract

Fe(II) participates in complex Fe-N cycles and effects on the microbial metabolism in the anaerobic ammonium oxidation (anammox) dominated system. In this study, the inhibitory effects and mechanisms of Fe(II)-mediated multi-metabolism in anammox were revealed, and the potential role of Fe(II) in the nitrogen cycle was evaluated. The results showed that the long-term accumulation of high Fe(II) concentrations (70-80 mg/L) led to a hysteretic inhibition of anammox. High Fe(II) concentrations induced the generation of high levels of intracellular ·O₂^-, whereas the antioxidant capacity was insufficient to eliminate the excess ·O₂^-, thus causing ferroptosis to anammox cells. In addition, Fe(II) was oxidized via nitrate-dependent anaerobic ferrous-oxidation (NAFO) process, and mineralized to coquimbite and phosphosiderite. They formed crusts on the surface of the sludge, leading to mass transfer obstruction. The results of the microbial analysis showed that the addition of appropriate Fe(II) increased the abundance of Candidatus Kuenenia, and served as a potential electron donor to enrich Denitratisoma, promoting anammox and NAFO coupled with nitrogen removal, while high Fe(II) concentrations reduced the enrichment level. In this study, the understanding of Fe(II)-mediated multi-metabolism in the nitrogen cycle was deepened, providing the basis for the development of Fe(II)-based anammox technologies.

Keywords: Anammox; Crusts; Fe-N network; Ferroptosis; Oxidative stress.

MeSH terms

Ammonium Compounds*
Anaerobic Ammonia Oxidation*
Anaerobiosis
Bioreactors
Denitrification
Ferrous Compounds
Nitrates / metabolism
Nitrogen
Oxidation-Reduction
Sewage

Substances

Sewage
Nitrates
Ammonium Compounds
Ferrous Compounds
Nitrogen