THE MICROBIAL COLONIZATION OF OIL PAINTINGS - A LABORATORY INVESTIGATION

Only a few bacterial and fungal species present in a soil extract grew and survived on painted canvases prepared utilizing the materials and following the recipes traditionally used for paintings. When pure cul tures of these microorganisms were used to contaminate such canvases, microbial growth and survival were even more reduced. On the other han d, on this substrate, the bacteria isolated from a heavily contaminate d XVIth century fresco grew to a limited extent, but remained viable f or a much longer period of time. Unlike the bacteria isolated from soi l, those isolated from the fresco were able to hydrolyse cellulose and proteins. It is thus possible that the capacity to utilize these macr omolecules may favour microbial survival on paintings. Furthermore, th e addition of phosphate strongly stimulates growth of all microbial sp ecies indicating that this anion is the limiting nutrient factor. Copy right (C) 1996 Elsevier Science Limited