The antagonistic activities of some metabolites produced by Pseudomonas aeruginosa Sha8.

Abstract

Some metabolites produced by Pseudomons aeruginosa zag2 had antagonistic activities against certain fungi. The antifungal activity of pyocyanin, siderophore and hydrogen cyanide produced by p. aeruginosa were studied. Pyocyanin was produced in King's B medium in pH 7±0.2 after 96 hours at 37 C and extracted by chloroform. Physico-chemical analyses showed that the extracted pigmented N compound was considered a derivative of phenazine PCN zag2. The minimum inhibitory concentration of this compound against Candida albicans was 40.69 µg/ml.The antifungal activity of this compound was remarkable at 100°C for 20 mins. Different morphological and ultrastructure changes induced after treatment of C. albicans by (PCN zag2) were detected by light and transmission electron microscope. This bacteria produced also another powerful antifungal compound called siderophore. Both pH values and iron concentrations were affecting the production and activity of siderophore. Finally, this bacteria produced toxic volatile compound (HCN) which reduced the growth of both F. oxysporium and Helmithosporium sp. while, A. niger was not affected.