Though numerous studies have been published on the physiological properties of Ps. aeruginosa. the requirements and mechanisms of pigment production have not yet been fully clarified.
From the structural similarity of anthranilic acid with the phenazine nucleus in pyocyanin, it was assumed that anthranilic acid may play a role as a precurser in the production of pyocyanin. In this paper the results of experiments on the effect of anthranilic acid on the pigment production of Ps. aeruginosa, using about 20 strains conserved in our laboratory, are presented and discussed.
When anthranilic acid alone is added to the basic medium (KH2PO4, MgSO4, (NH4)2CO3, NaCl) neither pigment nor fluorescence is produced. Addition of anthranilic acid in combination either with glycine & glycerol or with glutamic acid results in pigment production. It was found however, that the removal of anthranilic acid from the media dose not affect the pseudomonal pigmentation in the basic medium supplemented with glutamic acid alone, and pigment and fluorescence are rapidly produced with a difference in colouring according to each strain.
The isomers of anthranilic acid, kynurenin,3-hydroxyanthranilic acid and cathecol, each having a similar structure to anthranilic acid, do not affect the pigment production.
Differing from our expectation, these findings suggest that anthranilic acid has no effect, but glutamic acid plays a significant role in the pigment production of Pseudomonas aeruginosa.
