Biosurfactant Production from n-Paraffins by an Air Isolate Pseudomonas aeruginosa OCD1

The potential production of biosurfactant was investigated with a strain of Pseudomonas aeruginosa OCD(1), which was isolated from air in our laboratory. The degradation of different hydrocarbons was studied with this microorganism. The values of surface tension and emulsification index of culture broth were very promising when n-octadecane was used as substrate. Characterization of biosurfactant revealed that the biosurfactant was rhamnolipid in nature. The surface tension of water was reduced to 31.5 mN/m from 72 mN/m with the critical micelle concentration of 35 mg/L. A low rhamnolipid concentration (< 5 mg/L) had a strong effect on reduction of surface tension.