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Kinkarakawa-gami wallpapers are unique works of art produced in Japan between 1870 and 1905 and exported in European countries, although only few examples are nowadays present in Europe. So far, neither the wallpapers nor the composing materials have been characterised, limiting the effective conservation–restoration of these artefacts accounting also for the potential deteriogen effects of microorganisms populating them. In the present study, four Kinkarakawa-gami wallpapers were analysed combining physical–chemical and microbiological approaches to obtain information regarding the artefacts’ manufacture, composition, dating, and their microbial community. The validity of these methodologies was verified through a fine in blind statistical analysis, which allowed to identify trends and similarities within these important artefacts. The evidence gathered indicated that these wallpapers were generated between 1885 and 1889, during the so-called industrial production period. A wide range of organic (proteinaceous binders, natural waxes, pigments, and vegetable lacquers) and inorganic (tin foil and pigments) substances were used for the artefacts’ manufacture, contributing to their overall complexity, which also reflects on the identification of a heterogeneous microbiota, often found in Eastern environmental matrices. Nevertheless, whether microorganisms inhabiting these wallpapers determined a detrimental or protective effect is not fully elucidated yet, thus constituting an aspect worth to be explored to deepen the knowledge needed for the conservation of Kinkarakawa-gami over time.

Heat shock treatments are an innovative and eco-friendly method to devitalize biodeteriogens of outdoor stone monuments. They consist in short (up to 6 h), mild (40–60 °C) thermal treatments applied to artificially wet surfaces, and are effective against lichens and bryophytes. Epilithic green algae, a polyphyletic and diversified group of photoautotrophs, are among the most important colonizers of stone monuments, forming conspicuous biofilms which cause chemical, physical and aesthetical damage to the substratum. Like lichens and bryophytes, they are able to face the extreme conditions of a stone surface but their resistance mechanisms are only partially known. The present study aims to test the applicability of heat shock treatments to six morphologically and phylogenetically distant green microalgae. Their survival mechanisms have been investigated in relation to photosynthesis and content of selected polyols and non-reducing sugars. Chlorophyll a fluorescence measurements and observations at the epifluorescence microscope demonstrate that the thermal treatments cause negative effects on all the species, although they do not necessarily kill the whole populations, as observed in all the lichens and bryophytes tested so far. The survival capability is discussed in relation to the production of extracellular polymeric substances and non-reducing sugars.

A study was carried out on the biodeteriogenic vascular flora at the Royal Palace of Portici in southern Italy. In all, 160 species were found on the building, which represents approximately 35.5% of the flora found in the whole grounds (450 taxa). Ecological analysis of the plant population highlighted the decisive role of xeric climatic conditions, the lack of substrate, use of the site, and ordinary and restorative maintenance work. Therophytes (48.8%) broadly prevail over other biological forms. Most of the taxa censused (38.2%) may be considered ubiquitous and hence found at the same time on different types of substrate. Measured against the Hazard Index (HI), 62.5% of the species detected may be considered low-hazard (HI 0-3), 31.9% medium-hazard (HI 4-6) and 5.6% very hazardous (I.P. 7-10). Ailanthus altissima (Mill.) Swingle (HI 10), Ficus carica L. (HI 10) and Quercus ilex L. subsp. ilex (HI 9) were the species which had the most impact of the architectural structures in question A study was carried out on the biodeteriogenic vascular flora at the Royal Palace of Portici in southern Italy. In all, 160 species were found on the building, which represents approximately 35.5% of the flora found in the whole grounds (449 taxa). Ecological analysis of the plant population highlighted the decisive role of xeric climatic conditions, the lack of substrate, use of the site, and ordinary and restor- ative maintenance work. Therophytes (48.8%) broadly prevail over other biological forms. Most of the taxa censused (38.8%) may be considered ubiquitous and hence found at the same time on different types of substrate. Measured against the Hazard Index (HI), 62.5% of the species detected may be considered low-hazard (HI 0e3), 31.9% medium-hazard (HI 4e6), and 5.6% very hazardous (HI 7e10). Ailanthus altissima (Mill.) Swingle (HI 10), Ficus carica L. (HI 10), and Quercus ilex L. subsp. ilex (HI 9) were the species that had the most impact of the architectural structures in question.