CHARACTERISATION AND OPTIMISATION OF BIOSURFACTANT PRODUCED BY PSEUDOMONAS FLUORESCENS FROM OIL CONTAMINATED SOIL

Abstract

The biosurfactant producing strain Pseudomonas fluorescens was isolated from Dharmapuri District, Tamil Nadu.  India. The biosurfactant produced by Pseudomonas fluorescens was able to reduce the surface tension of media to 34.64 mN/m. Using FT-IR spectroscopy, the chemical structure of the purified biosurfactant was identified as lipopeptide. To enhance the biosurfactant production, optimization was employed by central composite design (CCD) in response surface methodology (RSM). In the optimization study, glucose as carbon source, yeast extract as a nitrogen source, pH and salinity (NaCl gL^-1) were assigned as a factor. The maximum emulsification index of Pseudomonas fluorescens was obtained under the optimal condition as glucose 20.28 gL^-1; yeast extract 2.51 gL^-1, pH at 7.01 and NaCl 5.37 gL^-1. The optimised production of biosurfactant yield was approximately increased to 2.2 folds. The results from this study showed that the biosurfactant produced by Pseudomonas fluorescens may have potential application in bioremediation.

KEYWORDS: Biosurfactant, Pseudomonas fluorescens, Lipopeptide, RSM, Emulsion index