Bioremediation of Crude Oil Contaminated Sea Water

Abstract

The bacterial strains Rhodococcus sp. S, Pseudomonas sp. S and Consortium M isolated from hydrocarbon contaminated sites in Skikda (Algeria) and Alexandria (Egypt) were tested for their ability to bioremediate crude oil contaminated sea water in lab microcosms. Different treatments including bioaugmentation, biostimulation and attenuation were tested. Ammonium nitrate was used as nitrogen source. Dissodium hydrogen phosphate and sodium dihydrogen phosphate were used as phosphorus sources. After six weeks crude oil degradation was between 70.5 and 95% except in the attenuation treatment (55.5%). The wheat straw immobilized cells enhanced crude oil degradation in comparison with free cells. The immobilized cells of Rhodococcus sp. S and Consortium M could degrade 88 and 91% respectively from 3% of crude oil in presence of Triton X-100 after four weeks. In absence of Triton X-100 they could degrade 89.5 and 90% respectively. The scale-up of lab microcosms revealed that the best results were obtained in bioaugmentation with immobilized cells of Consortium M. The increase in biodegradation of crude oil was correlated with an increase in dehydrogenase activity. The effect of crude oil toxicity was evaluated using local marine algae. The results revealed that bioremediated sea water had less toxicity in comparison with untreated one.