Use of salicylate to estimate the “threshold” inducer level for de novo synthesis of the phenol‐degrading enzymes in Pseudomonas putida strain H

Abstract

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/1.