ENHANCED BIODEGRADATION AND EMULSIFICATION OF CRUDE-OIL AND HYPERPRODUCTION OF BIOSURFACTANTS BY A GAMMA-RAY-INDUCED MUTANT OF PSEUDOMONAS-AERUGINOSA

A gamma ray-induced mutant of Pseudomonas aeruginosa strain S8, capabl e of hyperproduction of biosurfactant from hydrocarbons, was isolated and named as EBN-8. The mutant showed 3-4 times more hydrocarbon emuls ification/conversion as compared to the parent when grown on Khaskheli crude oil in minimal medium. Enhanced biosurfactant production and hy drocarbon utilization by the mutant was also observed during growth on heptadecane in minimal medium as indicated by emulsion index and surf ace tension of cell-free culture broth. Using heptadecane as carbon an d energy source, time course for the growth (cfu ml(-1)) and biosurfac tant production were compared for both parent and mutant. These studie s were carried out for 24 d at 30 +/- 2 degrees C and for 20 d at 37 d egrees C. Growth of EBN-8 was much faster compared to the parent as we ll as being 2-3 times more hyperproductive.