Use of salicylate to estimate the "threshold" inducer level for de novo synthesis of the phenol-degrading enzymes in Pseudomonas putida strain H.

A special approach was used to elucidate the "threshold" inducer concentration for coordinative de novo synthesis of phenol hydroxylase(s), catechol 2,3-dioxygenase and the 2-hydroxymuconic semialdehyde-metabolizing enzymes which initiate phenol catabolism in Pseudomonas putida strain H. It is based on cell-precultivation with glucose (as the carbon and energy source) in the presence of different concentrations of sodium salicylate which proved to be a potent non-metabolizable inducer in strain H of these enzymes. Subsequent estimation of the activity status of resting cell suspensions and cell-free extracts, respectively, prepared from those strain H cultures clearly revealed failing de novo synthesis of the mentioned phenol-degrading enzymes at salicylate concentrations lower than 0.2 mg/l.