Damage Caused by Microorganisms on Marble Samples

摘要

Tests to determine the alterative effects on Carrara marble of chemioautotrophic bacteria of the genus Thiobacillus and of two fungal strains isolated from the surface of the Pisa Tower have been carried out in our laboratories. In particular we looked for a correlation between: 1. Thiobacillus thiooxidans growth and changes in porosity of the samples. 2. Fungal growth and decohesion phenomena on marble. Results indicate structural and morphological changes in samples undergoing microbial attack. In particular, the development of T. thiooxidans leads to an increase in total porosity and a change in pore distribution. Fungal growth leads to production of oxalic acid which, by forming oxalates, leads to exfoliation phenomena.