SCREENING OF BIOSURFACTANT PRODUCTION BY BACTERIAL STRAINS ISOLATED FROM {SUDHANSHU SHEKHAR, 2015 #18}OIL CONTAMINATED SITES NEAR GAS STATIONS IN EGYPT.

Biosurfactant producing bacteria (28 isolates) were isolated from 30 oil contaminated soils and tested for production of biosurfactant by different screening methods. About 75% of the isolated bacteria showed no blood hemolysis and their emulsification index for hexane and xylene ranges from 28-35% and 30-45% respectively. Biosurfactant producing ability was confirmed by other tests where about 40% of isolates showed positive oil spreading activity, hydrocarbon overlay and 67% showed to be positive for drop collapsing test. 16s RNA sequencing of the most active isolates revealed one Stenotrophomonas maltophila, two Bacillus spp. and two Achromobacter spp. Biosurfactants extracted from these isolates showed variable antimicrobial activity against Staphylococcus aureus, E. coli and Pseudomonas aeruginosa. This study demonstrated that the biosurfactants produced by these bacteria could be used in combination with antibiotics for treating bacterial infections. Further study is required for enhancing biosurfactant production by bacterial isolates to be used environmentally for bioremediation of oil contaminated soils.