Bio-strategies for the conservation of lithic and metallic heritage

The stone material, the main constituent of historic buildings and monuments, and the metal finds deriving from archaeological excavations represent a part of our cultural heritage. Both are subject to deterioration linked to climatic conditions and habitats for various biota capable of colonizing surfaces and fissures, inducing aesthetic and structural damage. Usually, the organisms responsible for biodeterioration are controlled by synthetic chemical products, which, however, can represent a serious problem for the environment, the cultural heritage, and the operators’ health. To contribute to the protection of the environment and health, an ecological approach was tested. Extracts of Solanum nigrum L., Moricandia arvensis L, spontaneous plants, and secondary metabolites contained in the culture broth of fungus Beauveria bassiana Will. were used for environmentally friendly cleaning of the materials. All the extracts mentioned have shown high efficacy at low concentrations and have proven harmless from an environmental and toxicological point of view.