ماندانا زارعی

Most oil pollution in marine environments is the result of routine shipping operations, coastal oil re?nery ef?uents, industrial and municipal waste disposal, oil-spills caused by tanker accidents and blow-outs from off-shore oil-well platforms. The pollution impact of this event has been evaluated in several studies, all of which indicate that crude oil was accumulated and remained for a long time in the coastal area . The problem of oil pollution is particularly acute in an oil-producing area like the Persian Gulf because approximately 60% of the oil transport in the world is carried out in this marine environment Biodegradation by natural populations of microorganisms is the central and most reliable mechanism by which thousands of xenobiotic pollutants, including crude oil, are eliminated from the environment .Bioremediation is a strategy that utilizes biological activities to quickly eliminate envirmental pollutant. Bioaugmentation is the addition of microorganism capable of degrading the toxic hydrocarbons, in order to achieve a reduction of the pollutants. Biostimulation is the addition of nutrients needed by indigenous hydrocarbon degrading microorganisms in order to achieve maximum degradation of toxic compounds present in the oil. The degradation of hydrocarbons begins by the conversion of the alkane chain or polycyclic aromatic hydrocarbon (PAH) into an alcohol. Oxidation then converts the compound to an aldehyde and then into an acid and eventually into water, carbon dioxide, and biomass.