Utilization of dead biomass from an extremophilic yeast Meyerozyma sp. as a novel stabilization treatment for archaeological iron artifacts

This study aims to characterize and compare the performance of a treatment with biomass of Meyerozyma spp. versus a tannic acid inhibitor for the stabilization of iron artifacts retrieved from highly saline terrestrial sites. Treatments were applied on artificially aged steel coupon, where a mixture of akaganeite, magnetite, goethite and lepidocrocite mimic corrosion products on artifacts excavated from these sites. To assess the stabilization performance, optical microscopy, Raman spectroscopy and X-ray diffraction were employed. Results showed that using tannic acid, Fe—tannate complexes are formed but objects exhibit re-corrosion signs. In contrast, the use of Meyerozyma sp. biomass resulted in the conversion of active corrosion into magnetite, a more thermodynamically stable corrosion product, providing efficient stabilization.