TO COMPARE THE ANTIMICROBIAL POTENTIAL OF THE PROTONATED AND ZWITTERIONIC STATE OF BIOACTIVE PYOCYANIN ISOLATED FROM Pseudomonas aeruginosa.

Though Pseudomonas aeruginosa is medically important as an infectious agent due to its ubiquity , the emergence of this organism in the field of biotechnology is commercially valuable to date . The increasing scopes and interests in order to exploit the metabolites from this organism is a boon to the biotechnologists of this era. Pseudomonas aeruginosa is an opportunistic , Gram-negative bacterium responsible for severe nosocomial infections. The bluish secondary metabolite known as pyocyanin secreted by this bacteria is an important virulence factor. It has been reported that the redox active tricyclic pyocyanin is able to readily cross biological membranes, possessing antimicrobial activity (1, 2) and can exist in different states in various pH ranges. In our present study we have focussed on the comparision between the antimicrobial effects of the protonated and the zwitterionic state of this bioactive pigment pyocyanin against the Gram negative bacteria ( E.coli, , Vibrio cholerae) and the Gram positive bacteria (Bacillus subtilis). Pyocyanin was extracted from the broth culture by Chloroform /HCl technique and agar well diffusion method was followed thereafter to assay the antagonistic effects . The protonated (red) state in acidic environment was found to be more potent antimicrobial agent as compared to the zwitterionic (blue) state in neutral or slightly alkaline environment. The maximum zone of inhibition was noted for the acidic (red) state of pyocyanin against Gram positive Bacillus subtilis .Further high quality in vivo studies are needed to fully assess the physiological manifestations of pyocyanin exposure on the various cells including eukaryotic systems.