Pyocyanine formation by Pseudomonas aeruginosa

Although the production of a diffusible blue-green pigment, pyocyanine by Pseudomonas aeruginosa is one of the common place observations of bacteriology, many aspects of phenomenon remain to be explained. Burton, Eagles and Campbell (1948) and Ingledew and Campbell (1969a) showed, with the ATCC 9027 strain, that phosphate deficiency in the culture medium is one of the factors which induce pyocyanine synthesis. The object of this investigations were: (a) To confirm the earlier work on the role of phosphate deficiency and to explore the effect of altering other constituents of the medium. This was done with NCTC 6750, the type strain of P. aeruginosa. (b) To attempt to explain how to phosphate level of the medium regulates pyocyanine production. (c) To investigate the possible role of pyocyanine in the metabolism of the parent organism. To provide a chemical basis for the investigations, pyocyanine and some related phenazines were synthesized and considerable effort taken to characterize their absorption spectra in the ultra-violet, visible and infra-red regions