Biodegradation of phenol and sodium salicylate mixtures by suspended Pseudomonas putida CCRC 14365.

The biodegradation of single phenol and sodium salicylate (SA) and their binary mixtures in water by free Pseudomonas putida (P. putida) CCRC 14365 was experimentally studied at 30 degrees C and pH 7. The initial concentration of the cells, adapted with either phenol or SA, was maintained at 0.025 g/L. Single substrate experiments were performed in the substrate level range 0.53-3.18 mM. The Haldane model has shown that phenol was biodegraded more quickly (mu(max)=0.245 h(-1)) than SA (0.137 h(-1)) under the ranges studied, and SA had a more inhibitory effect on cell growth (K(I)=5.21 mM) than phenol (12.6 mM) at low substrate levels even by SA-adapted cells. Binary substrate experiments were carried out at two fixed total substrate levels of 1.06 and 3.18 mM, with a varying molar concentration ratio of 0.33-3.0. The presence of a small amount of phenol to SA could significantly enhance the biodegradation of SA, particularly when the phenol-adapted cells were employed. On the other hand, the addition of a small amount of SA to phenol would retard the biodegradation of phenol, especially at higher total substrate levels (3.18 mM).