The Oxidation of Aromatic Compounds by Fluorescent Pseudomonads

Abstract

Organisms of the Pseudomonas fluorescens species-group can utilize many simple aromatic compounds as sole sources of C and energy for growth. The attack is brought about in all cases by adaptive enzymes, and adaptation to this class of compounds is extremely specific. Complete, simultaneous adaptation to the attack on 2 or more aromatic substances after exposure to 1 of them occurs only if the compounds in question comprise members of a common reaction chain. Several lines of evidence indicate that dl-mandelic acid, benzoylformic acid, benzaldehyde and benzoic acid are successive members of an oxidative reaction chain. Benzyl alcohol also appears to participate (via benzaldehyde). There are in addition several other distinct primary oxidations of aromatic compounds by fluorescent pseudomonads, separate enzymatic mechanisms existing for the attack on phenol and on p-hydroxybenzoic and phenylacetic acids. dl-Mandelic acid is attacked without discrimination between the stereoisomers. These dissimilations all involve a far-reaching degradation of the benzene nucleus, and possible mechanisms for the attack on the benzene nucleus are discussed.