Ricerc@Sapienza

The tendency to employ natural products in the search for new eco-friendly solutions, according to the Green Chemistry principles, is spreading in many fields, including in the conservation of cultural heritage. In light of the above, the biocidal efficacy of three selected essential oils (C.nepeta, O.vulgare, T.vulgaris) and their respective major components (pulegone, carvacrol, thymol) has been assessed in a preliminary study that involved the application of these products, alone and/or in combination, on a biodegraded travertine wall. To have a systematic evaluation of the efficacy of this method, some travertine samples will be colonized with a phototropic multi-species culture and the products containing the phytochemical compounds, in different concentrations and compositions, will be applied. The preliminary phases of the project provide the physical and colorimetric characterization of the samples and the determination of their specific bioreceptivity. The inoculation of the samples with the biological culture will last three months and will be performed at the Dept of Edafología y Química Agrícola of the University of Santiago de Compostela, where this kind of procedure was ideated. The biocidal action of the phytochemical compounds on the biocolonized samples will be determined using i) colorimetric approach ii) quantification of photosynthetic pigments and extracellular polymeric substances iii) microscopic analysis. To better investigate the behavior and eventual changes of the physical properties of the stone in presence of the biofilm and the phytochemical compounds, portable NMR technology will be employed in an innovative way.