CHARACTERIZATION OF A PIGMENT PRODUCED BY PSEUDOMONAS FLUORESCENS DURING 3-CHLOROBENZOATE CO-METABOLISM

A strain of Pseudomonas fluorescens, designated CP30, was found to be able to co-metabolize 3-chlorobenzoic acid via 3-chlorocatechol and 4-chlorocatechol. These two intermediates seem to be involved in the darkening of the medium. The black pigments produced, which were recovered and purified from the CP30 cells and culture broth, have a number of chemical and spectroscopic characteristics typical of polyphenols. The analytical data and the results obtained from chemical degradation studies suggest that the structure of these halogenated bacterial pigments is closely related to that of the ''catechol-melanins'' of the plant kingdom described until now. Comparative chemical studies, including both bacterial pigments and 4-chlorocatechol polymers prepared in vitro, supported the hypothesis that CP30 pigments are ''chlorocatechol-melanins''. The production of the pigment seems to be responsible for a substantial modification of the CP30 cell shape.