Coniophora marmorata as responsible of a fungal outbreak in the Catacombs of SS. Marcellino and Pietro

Comunicación oral presentada en la S5.-Biodeterioration: Fundamentals, Present and Future Perspectives. Session in Honour of Prof. Cesáreo Sáiz Jiménez V del 3rd International Congress Science and Technology for the Conservation of Cultural Heritage.-- Technoheritage 2017 21-24th May 2017, Cádiz, SpainCave and catacombs microbiota and especially fungi are sensitive to organic input changes in their close environment. New input of organic sources (soil, dead animals and microorganisms, etc.) associated to favorable microclimatic parameters often lead to the overgrowth of fungi that may cover (colonize) a wide extension of available surfaces. The present research reports of a sudden fungal outbreak occurred in the corridor near the entrance of the Catacombs of SS. Marcellino and Pietro in Rome. A heavy fungal growth was observed one year after a restoration treatment that interested the walls of the entrance of the Catacombs and some artifacts placed in situ. Some marble slabs in fact, were restored and placed back into the walls. The colonization was observed only on the left side of the corridor around the marble slabs and on the vault. No growth was observed in the right side were similarly treated marbles slabs were placed. However, a high circulation of airborne fungal spores was observed. Mycological analysis were done on samples taken on the catacombs vault and side, as well as from soil and tree roots coming from upper ground above the catacombs. The combined use of microscopical, cultural and molecular tools showed that the vault and the left side of the corridor entrance were colonized by the brown Basydiomycetes Coniophora marmorata, that was able to form colonies with a diameter up to 57 cm, while secondary colonizations were due to different microfungi belonging to the genera Hypomyces chlorinigenus, Purpureocillium ilacinum, Acremonium persicinum, Penicillium spp. and Alternaria sp. The comparative analysis of roots and soils showed that fungi were present in all samples but a different distribution and diversity was observed. Due to the fast rate of growth of the fungi on the walls, a three steps emergency treatment was done with intervention on the environment, on the biodeteriogens and further by a close monitoring on monthly basis. Despite the successful intervention, it was clear that several causes could have created this fungal outbreak and for this reason, a continuous monitoring of the catacomb’s surfaces was planned. * Both Authors contributed equally in the isolation and characterization of fungal isolates.Peer reviewe