ISOLATION AND IDENTIFICATION OF ANTIALGAL SUBSTANCES PRODUCED BY PSEUDOMONAS-AERUGINOSA

Pseudomonas aeruginosa strongly inhibited the growth of green microalg ae and cyanobacteria by the release of low molecular weight, thermores istant factors. The antialgal substances were resistant to various enz ymes and remained active in agar after a 3-months storage period at 4- degrees-C in the absence of light. The results indicate that inhibitio n of algal growth was mediated by the phenazine pigments released by t he bacterium. Pyocyanine and an unidentified pale blue pigment had no effect on algal growth, whereas 1-hydroxyphenazine and oxychlororaphin e showed strong antialgal activity.