CHARACTERIZATION OF BIOSURFACTANTS PRODUCED BY PSEUDOMONAS AEROGINOSA NCIM 5514

Abstract

Surfactants as detergents and emulsifying agents are used in various fields of industry and agriculture. These amphiphilic compounds contain hydrophobic and hydrophilic fragments and are usually produced by large-scale chemical synthesis processes. However, recently there is a request to develop biotechnological methods to obtain surfactants, since biosurfactants have many advantages above their chemical analogues � higher tolerance to extreme temperatures, pH and salinity, higher stability and lower or zero negative environmental impact. Along with amphiphilic properties, surfactants produced by microorganisms may have additional properties such as inhibition of fungi or bacteria. The properties of biosurfactants are structure-dependent. Pseudomonas spp. are known to produce biosurfactants belonging to the rhamnolipids class. They consist of lipid tails and carbohydrate (mono- or dirhamnose) heads. In the present study, biosurfactants produced by P. aeruginosa strain NCIM 5514 isolated from oil-contaminated soil were characterized. The product was evaluated by the Fourier transform infrared spectroscopy with the identification of functional groups (OH- for 3302 cm-1, -CH2 and -CH3 at region from 2929 to 2881 cm-1 and -C=O at 1735 cm-1) which are specific to this class, the emulsification index E24 at 200 ppm was to 90%. Thin layer chromatography with the following dying confirmed the chemical composition by the presence of rhamnose fragments and fatty acid residues. It has been shown that the biosurfactant produced by P. aeruginosa is highly effective in terms of surfactant properties in various cleaning approaches, and at the same time, able to inhibit the activity of the pathogenic fungus Fusarium oxysporum in the test for the suppression of radial growth of fungi at doses of 500 and 1000 ppm.