A methodology to select bacteria able to remove synthetic polymers

Synthetic polymers have often been used for the protection and consolidation of cultural heritage. Although it was generally thought that synthetic polymers were not susceptible to deterioration, there are now many papers in the scientific literature demonstrating the opposite. The degradation of synthetic polymers can be due to chemical, physical and biological factors. At present, the traditional way for removing a degraded synthetic polymer is the use of mixtures of solvents that pose some health risks. This work proposes a method to select bacteria able to remove synthetic polymers from cultural heritage surfaces. The ability of five bacteria to attack Paraloid B72, the most commonly used polymer in conservation treatments, was evaluated by optical and scanning electron microscopy observations, weight loss measurements, Fourier transform infrared spectroscopy and differential scanning calorimetric analysis. Although none of the bacteria were able to attack Paraloid B72, the methodology developed can be applied to select other bacteria with this ability. Therefore the results offer insightful guidance to a better design of bioremoval experiments of synthetic resins used in conservation.