Biodeterioration agents dwelling in or on the wall paintings of the Holy Saviour’s cave (Vallerano, Italy)

Paint-degrading microorganisms

“…Similar results were obtained by the authors of articles [18,19], who studied mural paintings in Spain and Italy. Apart from the phyla mentioned above, researchers who wrote papers [20,21] [22][23][24].…”

Extremotolerant rock inhabiting black fungi from Italian monumental sites

“…Only in relatively few cases the fungal communities on rock surfaces were completely inventoried and still fewer species have been described and characterized phylogenetically. Earlier studies concerned marble monuments from historical sites in Greece Wollenzien et al 1995Wollenzien et al , 1997, more recently from Ukraine and Turkey (Bogomolova and Minter 2003;Sert et al 2007a, b, c) and, to a less extent, Italy (De Leo et al , 2003Zucconi et al 2012).…”

Characterization of the main colonizer and biogenic pigments present in the red biofilm from La Galea Fortress sandstone by means of microscopic observations and Raman imaging

“…As examples, in China, its presence has been found on rocks throughout a valley [25], in funerary sculptures from Argentina [26], in limestone monuments from Mexico [27], and in wall paintings colonizations from Italy [28]. Only one case of Trentepohlia sandstone colonization is referred in the literature, concretely in a Buddhist temple in Cambodia [29].…”

“…The main excreted pigment by red algae is β-carotene [33]. Trentepohlia algae filaments contain cells filled with carotenoid pigments, which are accumulated as a response to the light exposition, acting as a shield against photodecomposition and nitrogen deficiency [28]. These carotenoid pigments are observably crystallized in the globular cells (as example see Figs.…”

“…3C, D, E, F and 4F). These crystals are accumulated in the chloroplasts, to prevent the photodamage of the chlorophyll [25][26][27][28][29]34]. The formation of β-carotene crystals (orange-red) masks the real green color of the photosynthetic pigments of the algae, chlorophyll, giving as a result a red colored biofilm, instead of a green colored colonization.…”