BIODETERIORATION

The biodeterioration of organic and inorganic materials, as well as polymers, is a complex of alteration processes induced by the growing and metabolic activ- ity of organisms. It can be recognized on monuments, wall paintings, stone, wood, paper, vegetal/animal fibers, and parchment artworks. As defined by Hueck (1968), biodeterioration is “any undesirable change in the properties of a material caused by the vital activities of organisms”; this definition is accepted as the meaning of the phenomenon. Both macroorganisms (such as animals, plants and mosses) and microorganisms (such as autotrophic or het- erotrophic bacteria, microfungi, cyanobacteria, algae and lichens) represent the triggers of biodeterioration for cultural heritage. Understanding the mor- phological and physiological features of the biodeteriogens is required to establish the kind of interaction that occurs with the material and to assess the cause-effect of the biodeterioration action of a specific identified biological agent. For a complete evaluation of biodeterioration, a proper sampling and identification of the majority of biodeteriogens are required. Therefore, in order to apply a prompt and effective conservation to limit further damage, evaluating and quantifying the presence of biological systems that induce dam- age in heritage materials is indispensable.