A mutant of Pseudomonas putida with altered regulation of the enzymes for degradation of phenol and cresols

A mutant strain of $\text{Pseudomonas putida}$ NCIB 10015 has been isolated that is unable to utilize $\text{para}$-cresol as a sole carbon source. The mutant strain grows very poorly when $\text{meta}$-cresol is to be utilized but grows rapidly at the expense of phenol or $\text{ortho}$-cresol. Preliminary evidence is presented that this mutant strain has a regulatory element of altered specificity. This regulatory element determines the induction of all known enzymes involved in the metabolism of phenol and $\text{ortho, meta}$ and $\text{para}$-cresol. This is the first report of a mutation affecting the regulation of meta-cleavage enzymes.