Pyocyanin pigment assisting biosurfactant-mediated hydrocarbon emulsification

Abstract

A plethora of Pseudomonas strains was checked for their biosurfactant and pigment-producing abilities in Bushnell-Haas (BH) medium and proteose peptone glucose ammonium salts (PPGAS) medium. Five strains from different origins produced only biosurfactant in BH medium but both biosurfactant and pyocyanin pigment in PPGAS medium. Biosurfactant and pyocyanin exhibited a peculiar correlation as the culture supernatants containing both components emulsified hydrocarbons more than the biosurfactant alone. Enhancement in emulsification also occurred by mixing pyocyanin from PPGAS medium and biosurfactant from BH medium. Prior reports indicated that pigments protect producer strains from certain environmental stresses. The interesting finding of this study of pyocyanin pigment enhancing biosurfactant-mediated hydrocarbon emulsification was independent of the source of biosurfactant isolation. The synergistic action of pigment and biosurfactant found may be a general phenomenon for other Pseudomonas strains producing both biosurfactant and pigment, thus helping them to survive in arid conditions. The pigment-aided emulsification may help in lowering the requirement of biosurfactive agents for remediation purposes, which will also be helpful economically as the biosurfactants have very low yields. The enhancement in emulsification by the coupling of pigment with biosurfactant can have a significant impact in the paint industry and sectors dealing in environmental remediation.