Molecular and Physicochemical Characterization of Rhamnolipid Biosurfactant Produced by Pseudomonas sp JSK6

Interest in microbial surfactants like rhamnolipids has been progressively increasing in recent years due to their diversity, biodegradability and possibility of large scale production (Pinzon et al. 2013). However, traditional engineering by random and targeted genetic alteration, process design and recombinant strategies in rhamnolipid production were not studied in detail. Based on the environmental conditions, wide diversity of rhamnolipid congeners and homologues was produced in various bacterial strains (Abdel-Mawgoud et al. 2010). In this study, a biosurfactant producing bacterial strain, Pseudomonassp. JSK6 was isolated from hydrocarbonscontaminated sites at Madurai district of South India. The isolate produced mixture of both mono and di-rhamnolipidswith excellent surfactant properties. The critical micelle concentration (CMC) of the produced rhamnolipids was 30mg/L. The emulsification index of 56.4% with diesel and 55.3% with kerosene was quite stable after 24h. The culture condition optimisation showed that highest rhamnolipid (1.6g/L) production was achieved ∗ Corresponding author