SEM-FTIR spectroscopic evaluation of deterioration in an historic coffered ceiling.

Microorganisms generally degrade wood when moisture, oxygen and other environmental factors provide favorable growing conditions. Scanning electron microscopy (SEM) and Fourier transform infrared spectroscopy (FTIR) were used to study the development and transformation of the products formed during the biomineralization process that follows the deterioration of wood from an historical coffered ceiling (Cloister of St Francesc (XIV century), Palma de Mallorca, Spain). After fungi colonization, cellulose and lignin disappear and inorganic salts are formed. Thus, the secretion of numerous acids (initially oxalic acid) by fungal hyphae also leads to the precipitation of authigenic salts. Damaged cells or tissues enhance the formation and growth of crystals, which is strongly favored by fungi that function as calcification nuclei. Finally, the presence of dihydrated calcium sulfate reveals the contribution of environmental factors to the weathering of wood.