**2.2. Selection of potential phenol-degrading strains**

The ability of the isolates to grow with phenols added was evaluated using Mineral Salt Medium (MSM), a synthetic medium containing K2HPO4 (1.6 g/l), KH2PO4 (0.4 g/l), NH4NO3 (0.5 g/l), MgSO4\*7H2O (0.2 g/l), CaCl2 (0.025 g/l), FeCl2 (0.005 g/l), Agar (12 g/l), cinnamic (C9H8O2) or vanillic acids (C8H8O4) (0.5 or 1 g/l; Sigma-Aldrich, Milan, Italy). After streaking the isolates onto the surface of this modified medium, the plates were incubated at 30°C for mesophilic bacteria and *Bacillus* and at 25°C for *Pseudomonadaceae* for 72 h. MSM without phenolic compounds was used as control. For a second assay, the isolates were preliminary grown in MSM broth added of 0.025 g/l and 0.05 g/l of cinnamic and vanillic acids and incubated for 24 h; thereafter they were streaked onto the surface of MSM with phenols, as reported above.
