Siderophores are common organic molecules that are exudated by a range of microorganisms for the access of iron (Fe) from low solubility Fe(III)-contain minerals. However, due to their highly localized nature and low concentration at bulk scale, these molecules and their cell associations are hard to detect. This study aims to develop a synchrotron based spectromicroscopic method to detect and characterize the identification and spatial distribution of siderophores and other metabolites released by lichens on an insoluble Fe oxide mineral hematite. Several lichen species were examined, including the crustose lichen species Rhizocarpon geographicum ssp. geographicum and the foliose lichens species Brodoa intestiniformis and Parmelia saxatilis. Near-edge X-ray absorption fine structure (NEXAFS) spectroscopy revealed specific signatures for standard siderophores and other lichen metabolites, at both carbon and nitorgen K-edges. Scanning transmission X-ray microscopic (STXM) analysis provided spatially resolved energy signatures across a sample. The combination of NEXAFS and STXM analysis revealed the spatail distribution of siderophores and other metabolites around the lichen samples. This method is not only applicable to the interface weathering system between lichen and hematite, but can also be used to study other microbe-mineral interactions.

Resolving the spatial distribution of siderophores and other metabolites at lichen-mineral interface

255th National Meeting (2018)

The official archive and repository for all ACS Meetings & Expositions abstracts and select posters or presentations.