ABSTRACT
The churches of Veracruz and San Ignacio are two of the most characteristic examples of the cultural heritage of the city of Medellin, Colombia. Biodeterioration effects are assessed by using microbiological techniques of isolation and culture, complemented with optical and scanning electron microscopy (SEM) observations. The impact of atmospheric factors on the structural material is studied by using three different surface analysis techniques: energy dispersion X-ray analysis, X-ray diffraction and Fourier transform infrared spectroscopy complemented with SEM and petrographic analyses. In addition to biodeterioration processes, the environment plays a relevant role in the type and extent of material decay because relative humidity, temperature and natural and anthropogenic pollution enhance the effects of biodeterioration. Microbial biodeterioration is due to the presence of biofilms which are biological deposits of a highly hydrated gel of extracellular polymeric substances containing microbial cells and inorganic detritus.
