Evaluation of mural paintings biodeterioration by oxalate formation.

The aim of this work is the isolation and identification of the microbial communities involved in the biodeterioration phenomena affecting the wall paintings of the Convento de Nossa Senhora da Saudação (Montemor-o- Novo, Portugal) and the identification of a pigment deterioration product caused by oxalic acid, in order to plan appropriate restoration treatments.The combined spectroscopic approach using scanning electron microscopy coupled with energy dispersive X-ray spectrometry (SEM) and Raman microscopy allowed to evaluate the microflora proliferation and the presence of oxalates, respectively, and proved to be a useful tool for the biodeterioration assessment in mural paintings