Screening Bacterial Strains Isolated from Used Motor oil-Polluted Desert Soil for the production of Biosurfactants and the Possibility of Applying the Produced Biosurfactants for Washing and Bioremediation of the Polluted Soil

Six bacterial strains were previously isolated as hydrocarbon degraders from spent motor oil polluted desert soil. The six isolates were Arthrobacter sp (EM2) Bacillus Subtilis (EM6), Bacillus sp (EM10), Corynebacterium sp (EM14) Pseudomonas aeruginosa (EM1) and Pseudomonas sp (EM19). The six bacterial strains were screened for biosurfactant production. Pseudomonas aeruginosa (EM1) and Pseudomonas sp (EM 19) were succeeded to produce biosurfactants of high activities (118.8 8.2 and 89.0 3.6 ODA cm2 respectively), of higher stability under wide range of temperature, pH and NaCl E24 values against petroleum oil. These characters give these biosurfactants potential applications in enhanced bioremediation of polluted sites, cleaning oil storage tanks, enhanced microbial oil recovery (EMOR) and recovery of oil from oily sludge. The sterilized supernatant containing the biosurfactant produced by Pseudomonas aeruginosa (EM1) was selected and applied directly to the spent motor oil- polluted soil. The results show that addition of biosurfactant- NP and biosurfactant alone resulted in higher biodegradation of the pollutant (71.3 5.2 % and 68.5 3.2 % respectively) with no significant variation between the results. As a conclusion, addition of biosurfactant alone for the bioremediation of polluted sites will reduce the cost of bioremediation processes and minimize the dilution or wash away of the soluble nutrients that may be used for bioremediation of water.