微生物介导铁还原耦合氨氧化过程的研究进展

Microbes-mediated coupling of Fe(Ⅲ) reduction and ammonium oxidation

摘要:

铁的氧化还原过程可以显著影响环境中次生矿物的形成、养分转化和污染物的归趋。作为厌氧环境中新发现的铁循环过程，铁氨氧化过程对自然和农田生态系统中氨氧化的贡献可达10%以上，对环境保护和农业生产具有深远的意义。文章主要从发展历程、相关微生物、反应机制、影响因素和环境意义等方面综述了铁氨氧化过程。在此过程中，Acidimicrobiaceae sp.A6和异化铁还原菌(DIRB)是驱动铁氨氧化过程的关键微生物，环境pH、Fe (Ⅲ)的浓度和种类、碳源和Mn ()Ⅳ氧化物是重要环境影响因子。铁氨氧化过程可能由微生物独立驱动完成，也可能由微生物-化学耦合作用驱动完成。从环境意义看，铁氨氧化过程对减少温室气体排放、固定重金属等方面具有积极影响，但也会导致氮素流失等负面环境效应。后续的研究可以从纯化微生物、拓展研究方法等方面着手，进一步提升铁氨氧化过程的研究广度和深度。

Abstract:

The redox processes of iron significantly influence secondary mineral formation, nutrient transformation, and the fate of contaminants. As a novel process of global iron cycle first discovered in anaerobic environment, microbes-mediated coupling of ammonium oxidation and Fe(Ⅲ) reduction (Feammox) accounts for up to 10% of ammonium oxidation in natural and agricultural ecosystems. Thus, it is of great significance for environmental protection and agricultural production. This review summarized the research on microbial Feammox in recent years, including its research history, related microbes, underlying mechanisms, influencing factors, and environmental significances. In Feammox, Acidimicrobiaceae sp. A6 and dissimilatory Fe-reducing bacteria (DIRB) are potential functional organisms, and pH, Fe(Ⅲ) concentration and speciation, carbon sources, and Mn(Ⅳ) oxides are the main environmental factors. Feammox might be driven by biological process alone, or by the biological-chemical coupling processes. As for the environmental significances, Feammox can reduce the greenhouse gas emission and influence heavy metal transformation, but it causes alternative N loss. Further investigations could focus on the cultivation of related microorganisms and the development of new research methods to further disclose the Feammox mechanism.