Microbial communities and alteration processes in monuments at Alcala de Henares, Spain

Fungi belonging to the genera Alternaria, Penicillium, Phoma, Trichoderma, Mucor, Ulocladium, Dictyodesmium and Phialostele colonize the building materials of several monuments at Alcala de Henares (Madrid, Spain). Bacteria of the genera Bacillus, Micrococcus and Thiobacillus were also isolated. Microbial activity in the surface layers of the stone was determined following the dehydrogenase activity test. Gypsum formation and weathering of some mineral components (e.g. feldspar, mica and calcite) were shown by FT-IR and SEM-EDX, as well as an enrichment in S due to air pollution and in P due to biological input.