Hydrolates and Gellan: An Eco-innovative Synergy for Safe Cleaning of Paper Artworks

The gellan hydrogel is used as a cleaning agent for paper artworks. The purposes of this work were to give the gellan hydrogel both a microbial resistance and a cytocidal action against the biodeteriogens using hydrolates. Broth microdilution assays were performed to identify the fungicidal action of 16 hydrolates vs 3 fungal strains. The study concerned the Minimal Fungicidal Concentration and pH, colour, and ultra-structural variations on all paper samples, by placing them in contact with GELYD (GELlan + hYDrolat). The in vitro tests showed that eight out of 16 hydrolates strongly inhibited fungal growth, but only two of them (Monarda fistulosa, Citrus aurantium subsp amara) showed in situ fungicidal action. Data indicate a new and interesting eco-innovative use of hydrolates, since GELYD is able not only to clean paper artworks, but also to kill the fungal cells present on paper that are potentially harmful for paper and operators.