MinOx

Geomicrobiology of Fe(II)-bearing Minerals and Nitrate-Reducing Iron-Oxidizing microbial cultures

01.05.2024 bis 30.04.2026

Nitrate-Reducing Iron-Oxidizing (NRFeOx) microorganisms, which couple Fe(II) oxidation to nitrate reduction using organic matter or
carbon dioxide as a carbon source, play an essential role on a global scale in three of the most important biogeochemical cycles: iron,
carbon and nitrogen. From an ecological point of view, NRFeOx microorganisms are key players in several processes such as the
biological oxidation of Fe in anoxic and dark environments, the reduction of atmospheric carbon dioxide and the removal of nitrate
from polluted groundwater aquifers.
The aim of this project is to analyze the ability of NRFeOx communities to thrive using Fe(II)-bearing minerals as an energy source, the
ecological consequences of the mineral transformation, and to explore the mechanism of microorganism-mineral interaction, which
is crucial to fully understand their role in natural environments. First, culture techniques will be applied to identify Fe(II)- bearing
minerals that can be oxidized by NRFeOx communities. Subsequently, Molecular Biology techniques will be applied to analyze the
structure and distribution of NRFeOx communities when they grow using minerals as an energy source and to determine the main
actors in the process. Finally, analytical microscopy techniques will be used to study, at the nanometer scale, the interaction between
specific microorganisms with the mineral surface. For this purpose, state-of-the-art techniques such as Confocal Raman Microscopy,
Scanning Electron Microscopy-Energy Dispersive X-Ray Spectroscopy and X-Ray Photoemission Electron Microscopy will be
correlated with Fluorescence In Situ Hybridization and Fluorescence Microscopy.
The data obtained in the MinOx project could not only be applied to biotechnological processes and integrated into predictive
models for the management of nitrate-contaminated waters but will also unveil a totally unknown area of geomicrobiology: the
transformation of Fe(II) minerals by NRFeOx microorganisms.