Biogeochemical cycles of iron: Processes, mechanisms, and environmental implications.

ABSTRACT

The iron (Fe) biogeochemical cycle is critical for abiotic and biological many environmental processes, both abiotic and biological, that overlap spatially and may compete with each other. The development of modern molecular biology technologies has promoted an understanding of the electron transport mechanisms of Fe-cycling-related microorganisms. Recent studies have revealed a novel pathway for microaerophilic ferrous iron (Fe(II))-oxidizers in extracellular Fe(II) oxidation. In addition, OmcS, OmcZ, and OmcE nanowires on the cell surface have been shown to promote electron transfer between microorganisms and their environment. These processes directly or indirectly affect the fate of pollutants, including greenhouse gas emissions. This review discusses these advances and the environmental implications of the Fe cycle process, with a particular focus on the mechanisms of intracellular or extracellular electron transport in microorganisms.