Pseudomonas aeruginosa is a common inhabitant of soil, fresh-water and marine environments. Pyocyanin is one of the stronger antimicrobial substance produced by this bacterium inhibiting a wide range of pathogenic microorganisms. In order to exploit the antimicrobial and antioxidant effects of pyocyanin and abrogate some pathogenic microbes responsible for several diseases, three strains (P1, P2 and P3) of Pseudomonas aeruginosa were isolated from saline soil of Mina river region (Relizane, Algeria). The higher producer of pyocyanin (P3) was selected for further studies. Pyocyanin was produced in King A broth medium, extracted with chloroform then purified by silica gel chromatography. The characterization of the metabolite by UV spectrum, TLC, IR and HPLC revealed a similarity with the pyocyanin standard. The effect of NaCl on pyocyanin production was determined by using different concentrations and the maximum amount was detected in the medium containing 20g/l. The antimicrobial effect results showed varying degrees of inhibition zones against the microorganisms tested and the remarkable effect were detected against Candida albicans ATCC 10231 and Bacillus cereus ATCC10876 with zones diameters of 26 mm and 14 mm respectively. Hemolytic activity using human blood was obtained above 5mg/ml and the IC50 value of the antioxidant activity of pyocyanin with DPPH method was evaluated at 3.15µg/ml.
