Abstract

In this present study, biosurfactant-producing microorganisms Pseudomonas aeruginosa PBSC1, was isolated from mangrove ecosystem in Pichavaram (Boat house), Tamil Nadu, India. The biosurfactant production was done using a minimal salt medium (MSM) with crude oil as the hydrocarbon. The microbial growths were investigated, and the best cultivation times for the biosurfactant production by P. aeruginosa PBSC1 was found to be 144 h. The biosurfactant was extracted and characterized. The critical micelle concentrations (CMCs) of extracted biosurfactant was found to be 78 mg l^-1. Stability studies were done at various pH, temperature and NaCl concentrations. The emulsification activity was stable at lower and higher pH and temperature respectively. NaCl concentration does not affect the emulsification activity of the biosurfactant. The emulsion formed by the biosurfactant against each hydrocarbon was stable for one month. Further characterization of biosurfactant using Fourier transform infrared spectroscopy (FTIR) revealed it as a rhamnolipid.

Key words: Mangrove ecosystems, Pseudomonas aeruginosa, biosurfactant, critical micelle concentration (CMC), FT-IR fourier transform infrared spectroscopy (FTIR).