P84: Rhamnolipids and fatty acids homologues produced from different carbon sources by Pseudomonas aeruginosa 2A1

Rhamnolipids are among the most studied biosurfactants, they are able to reduce water surface tension of 72 mN /m to 30 mN /m and the CMC ranging varies from 5 to 200 mg / L, which is dependent of the counterparts proportion in the mixture. Currently there are about 60 described rhamnolipids counterparts produced by Pseudomonas and other families. The properties and applications of this biosurfactant depend on the composition and distribution of homologues, which in turn are determined by the strain, cultivation conditions and medium composition. Thus, the aim of this study was to evaluate the relationship between carbon source and rhamnolipids counterparts produced by P. aeruginosa 2A1. Thereby, the strain was cultivated in mineral medium, using castor oil, corn soapstock and sunflower oil as carbon source. Then biosurfactant extraction was made and analyzed by mass spectrometry ESI (-) /MS. For rhamnolipids homologous there were predominance of mono and di-rhamnolipids, RhaC10C10/ RhaRhaC10C10, respectively. However were observed differences in the composition and proportion of fatty acids produced from each carbon source. The sample from the culture with castor oil showed the most different fatty acids. The fatty acid β-di-hydroxy tetradecenoil presented relative abundance of 84% for the cultivation with castor oil, and was not detected in the cultures of the two other carbon source, the structure of this may be related to the molecule of ricinoleic acid, main component of this carbon source, which has a hydroxyl at C₁₂, and further added an OH during the synthesis of β-di-hydroxy tetradecenoil.