Biodeterioration of some cultural heritage in Isfahan City, Iran

The aim of this study was to isolate and phenotypical identification of microorganisms involving in biodeterioration of four historical places in Isfahan, Iran. For this purpose two hundred and ten samples were taken from the stones of Chehel Sotoun, Hasht Behesht, Alighapou and Imam mosque. For bacterial isolation blood agar and modified Bristol medium were used and for screening of fungal isolates potato dextrose agar was used. Then the samples were serially diluted and poured on the selected media. For bacterial isolates the plates were incubated at 30°C for 48 hrs and for fungal isolation the plates were kept at room temperature for 4 weeks. The pure colonies were identified using phenotypical and molecular identification. Fungi were characterized using macroscopic characteristics and microscopic arrangements. The results obtained from this study indicated that the dominant isolated bacteria were Bacillus licheniformis, Bacillus thuringiensis and Halomonas sp. In addition the results showed that the fungal isolates belonged to Genus: Alternaria, Cladosporium, Penicillium, Absidia and Shaccharomyces. Furthermore, the most polluted area was Chehel Sotoun which is located in the traffic part of the city. Overall, stone materials of cultural heritage are constantly exposed to biodegradation by microorganisms and presence of organisms including algae, fungi and bacteria are likely to affect or even cause physico-chemical changes.