Jiang Yushi, Chen Yuqi, Wang Ying, Chen Xueming, Zhou Xuanfan, Qing Kexin, Cao Wenzhi, Zhang Yanlong
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 Provincial Engineering Research Center of Rural Waste Recycling Technology, College of Environment and Safety Engineering, Fuzhou University, Fuzhou 350116, China.
Water Res. 2023 Aug 15;242:120291. doi: 10.1016/j.watres.2023.120291. Epub 2023 Jun 29.
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 ·O, whereas the antioxidant capacity was insufficient to eliminate the excess ·O, 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.
亚铁离子（Fe(II)）参与复杂的铁-氮循环，并对以厌氧氨氧化（anammox）为主导的系统中的微生物代谢产生影响。本研究揭示了Fe(II)介导的多代谢过程对厌氧氨氧化的抑制作用及其机制，并评估了Fe(II)在氮循环中的潜在作用。结果表明，高浓度Fe(II)（70-80 mg/L）的长期积累导致厌氧氨氧化受到滞后抑制。高浓度Fe(II)诱导细胞内产生高水平的超氧阴离子（·O），而抗氧化能力不足以消除过量的·O，从而导致厌氧氨氧化细胞发生铁死亡。此外，Fe(II)通过硝酸盐依赖的厌氧亚铁氧化（NAFO）过程被氧化，并矿化为铁明矾和磷铁矿。它们在污泥表面形成结壳，导致传质受阻。微生物分析结果表明，添加适量的Fe(II)可增加厌氧氨氧化菌“库氏菌属（Candidatus Kuenenia）”的丰度，并作为潜在的电子供体富集脱氮索氏菌属（Denitratisoma），促进厌氧氨氧化和NAFO与氮去除的耦合，而高浓度Fe(II)则降低了富集水平。本研究加深了对Fe(II)介导的氮循环多代谢过程的理解，为基于Fe(II)的厌氧氨氧化技术的发展提供了依据。
