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The Fishing House located on the grounds of the Marquis of Pombal Palace, Oeiras, Portugal, was built in the 18th century. During this epoch, Portuguese gardens, such as the one surrounding the Fishing House, were commonly ornamented with glazed wall tile claddings. Currently, some of these outdoor tile panels are covered with dark colored biofilms, contributing to undesirable aesthetic changes and eventually inducing chemical and physical damage to the tile surfaces. Phylogenetic analyses revealed that the investigated biofilms are mainly composed of green algae, cyanobacteria and dematiaceous fungi. With the aim of mitigating biodeterioration, four different biocides (TiO 2 nanoparticles, Biotin ® T, Preventol ® RI 80 and Albilex Biostat ® ) were applied in situ to the glazed wall tiles. Their efficacy was monitored by visual examination, epifluorescence microscopy and DNA-based analysis. Significant changes in the microbial community composition were observed 4 months after treatment with Preventol ® RI 80 and Biotin ® T. Although the original community was inactivated after these treatments, an early stage of re-colonization was detected 6 months after the biocide application. TiO 2 nanoparticles showed promising results due to their self-cleaning effect, causing the detachment of the biofilm from the tile surface, which remained clean 6 and even 24 months after biocide application. © 2013 Society for Applied Microbiology and John Wiley & Sons Ltd., (© 2016 Society for Applied Microbiology and John Wiley & Sons Ltd.)

Lascaux Cave in France was discovered in 1940. Since being opened to visitors the cave has suffered three major microbial outbreaks. The current problem is the fast dissemination of black stains which are threatening the Palaeolithic paintings. Previous data pointed to the involvement of new fungal species in the formation of black stains on the rock walls and ceiling. However, it appears that there could be other reasons for the formation of different and extensive black stains coating the surface of the clayey sediments. Our analyses reveal that black stains on clayey sediments are mainly produced by Acremonium nepalense, a manganese oxide-depositing fungus, widely distributed in the cave. Thus, in Lascaux Cave, the black stains have a dual origin: on limestone rocks they are mainly produced by the accumulation of fungal melanins, and on clayey sediments by the biogenic deposition of black manganese oxides., (© 2012 Society for Applied Microbiology and Blackwell Publishing Ltd.)