Calorimetric investigations on the metabolism of Bacillus strains isolated from artistic stoneworks

In the study on the deterioration of artistic stoneworks the possibility to relieve the presence of deteriorative microorganisms on the alterations is becoming evermore important. The spore-forming microorganisms belonging to Bacillus genus are often present in the biological alterations; these bacteria are very common and their caracteristic habitat is the soil, but they are also isolated from different other matrices, as the altered stone of monuments. Their role in the biodeterioration is particularly important for the capability to produce resistant forms, the spores, that permit the resistance to stressing envirnmental conditions. The aim of this work is to study the calorimetric behaviour and characterize the various phases of the cellular cycle of different Bacillus strains isolated from stonework alterations (B.cereus, B.subtilis e B. alvei) and verify if it is possible to obtain from the calorimetric signals significant differences that permit the marking of the single specie. Furthermore in every test carried out using spores a fall of the calorimetric signal results more evident, compared to tests performed with vegetative cells.