TITLE: Characterization of the biodeterioration and development of new cleaning treatments applied to the restored frescoes of Antonio Palomino in the Santos Juanes church of Valencia.

SUMMARY:
This research focuses on the study of the frescoes painted by Antonio Palomino (XVII) in the central vault of the Santos Juanes church of Valencia and restored by Gudiol in the 60's. The paintings are composed of both inorganic materials (from the frescoes) and organic materials (mainly due to the restoration). The components of the paintings may experience biodeterioration processes with a consequent change on its aesthetic, physical, mechanical and chemical properties. The main objective of this thesis is the study of the biodeterioration of the wall paintings presents in the church and the formulation of a biological intervention proposal. In order to do this, we characterize the original materials, compounds and treatments that were applied in previous restorations, to determine which are susceptible to biodeterioration. We used different analytical techniques such as Optic and Electronic Microscopy (SEM/EDX), Fourier Transform Infrared Spectroscopy (FTIR), Gas Chromatography-Mass Spectrometry (GC/MS) and Pyrolysis (Py-GC-MS). On the other hand, it is determined the contamination state of the paintings through the study of environmental conditions and the identification of microorganisms. With this objective, isolation, culture, recount and identification of microorganisms is done by light microscopy, biochemical tests and molecular biology techniques. It is also evaluated the resistance to biodeterioration of the materials used in restoration. And finally, it is developed a new alternative method for wall painting cleaning based on the use of microorganisms (Pseudomonas stutzeri) to removal organic matter and efflorescence. Biocleaning tests are performed first in the laboratory, and later applied on the frescoes of the church.

The most outstanding results are: The identification of three lichenic genus, Caloplaca, Lecanora and Candelariella able to bioaccumulate heavy metals; the presence of high levels of airborne microorganisms inside the church, 151-400 UFC/m3, identifying Aspergillus and Penicillium as the most common fungal genera; and the recognition by molecular biology techniques in the restored frescoes, bacteria from the Bacilli class and fungi from the Aspergillus and Penicillium genus. It has been prove the high susceptibility to biodeterioration of wood and cotton support used in the previous restoration, and the high resistance to biodeterioration of the new aluminum and carbon fiber support being used in the current restoration. Finally, there are shown great results of biocleaning, mainly sulfates, using Pseudomonas stutzeri applied with a new delivery system: agar.