Utilization of Oil Industry Residues for the Production of Rhamnolipids by Pseudomonas indica

In the present work, a new strain Pseudomonas indica MTCC 3714 was studied for the production of biosurfactants using various rice-bran oil industry residues viz. rice-bran, de-oiled rice-bran, fatty acids and waxes. Among all the carbon sources, a maximum reduction in surface tension (26.4 mN/m) was observed when the media were supplemented with rice-bran and the biosurfactant was recovered using the ultrasonication technique as one of the steps in the extraction process. Biosurfactants were obtained in yields of about 9.6 g/L using rice-bran as the carbon source. The structure of the biosurfactants as characterized by FT-IR, NMR (H-1 and C-13) and LC-MS analysis revealed that the majority of the biosurfactants were di-rhamnolipids. The biosurfactants produced were able to emulsify various hydrocarbons and showed excellent potential in microbial enhanced oil recovery, as it was able to recover kerosene up to 70 % in a sandpack test.