Innovative biological approaches for metal conservation

While often considered as harmful for cultural heritage, microorganisms can also be used for its safeguarding. Two research projects (BIOPATINAS and MAIA) using the capabilities of microorganisms for the conservation-restoration of metal artistic and archaeological objects are presented in this study. The objective of the BIOPATINAS project is to propose an alternative biological treatment for copper alloys artefacts. Taking advantage of unique properties of carefully selected fungal strains, the project relies on the conversion of existing corrosion patinas into more stable copper oxalates. The results demonstrated a different weathering behavior of the biopatina compared to standard treatments such as waxes or inhibitors. In the MAIA project, the unique capacities of some fungi and bacteria are studied for the stabilization of archeological iron. Based on the results achieved, a synergetic microbial consortium will be designed for the formation of stable iron compounds and the simultaneous removal of chloride ions that are the instigators of further corrosion after excavation. A careful assessment of the methodology is currently carried out over iron- and chloride-rich phases.