Effetti della colonizzazione di microorganismi fotosintetici sul patrimonio artistico: caratterizzazione morfologica e molecolare degli organismi e possibili tecniche di controllo.
[Tesi di dottorato]
Dissertation title: The effects of colonization of photosynthetic microorganisms on the cultural heritage: morphological and molecular characterization of microorganisms and possible control techniques.
Doctoral candidate: Chiara Marzano
The purpose of my dissertation is the study of bioincrustations (prevalently produced by microorganisms, such as bacteria, cyanobacteria and microalgae, but by mosses as well) growing on monuments and on exposed surfaces of archaeological sites and the development of new protocols for to remove them. A non destructive technique was employed to collect biofilms from eight sampling sites located in different places of Naples and surroundings. The substrates were either yellow tuff or piperno, two locally abundant volcanic rocks.
Various molecular techniques (DNA extraction, enviromental PCR, cloning and DGGE) were employed for identification and classification of the biofilm organisms. Experiments of controlled growth of biofilms in artificial environments were carried out in a a climatic chamber thanks to the cooperation of Prof. Cesareo Saiz-Jimenez of the CSIC in Seville. Different environmental conditions were simulated, in order to verify whether the different microclimatic parameters (humidity, sun exposure, temperature) may influence the distribution and composition of microbial biofilms.
Specific protocols were designated, aiming at monitoring and eradicating bioincrustations, according to the identification of biodeteriorating microorganisms on the two substrates, as well as of microclimatic parameters influencing biofilm formation.. The proposed protocols do not alter the chemical nature of the substratum and are based on the use of biocides and cold microwaves. The knowledge of bioincrustation-forming organisms allowed to establish appropriate value ranges of microwave intensity.
Results indicated that using microwaves is certainly the most appropriate method, because it does not cause alterations to the surfaces of the substrates, does not contribute to environmental pollution, and it is less hazardous for operators.
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