During the restorations carried out in the reading rooms of Palazzo Piatti Reghenzani in Teglio, located on the first floor, two cycles of frescoes inherent biblical scenes present in the Old Testament were revealed. In the room referred as “1” there was the possibility to use bacteria for cleaning, through samples located in significant areas. Through these tests it was possible to highlight the difference between a classic chemical and an experimental cleaning with bacteria. The substantial difference is due to the selectivity of bacteria, which act without affecting the pictorial layers, but only on the deposit. The works involved, in addition to the cycle of frescoes, the settlement of the secondary building and the valorisation of the garden.