Application of Bacteria in Removing the Oil Pollutants from the seas & coasts

[ Maryam Nassiri ] - Maryam Nassiri Azar was born in 1976 in Tehran-Iran. She received her B.Sc on 1998 from Azad University of Tehran shomal.She obtained her master grade in Microbiology in 2001 from azzahra University of Tehran .At present she is the Researcher and manager of research & inquiry’s group of Green West Asia Biotechnology Centre.

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Recent developments in the biology sciences, particularly in molecular biology, have demonstrated a high potential for application in different industries. In the petroleum industries microorganisms and their products can play an important role in oil recovery (MEOR-Microbial Enhanced Oil Recovery), petroleum de-asphalting, viscosity control, desulphurization, oil spill control, waste management and detoxification (2). The oil spillage in marine environments has been heralded as one of the worst ecological catastrophes in history; for example the Iran/Iraq war resulted in a total oil spillage of about two million barrels, about one fifth the size of the current spill. This caused relatively modest ecological damage (8). The major question is what the fate of oil pollutants in the seas is? Degradation of crude oil depends on composition, concentration, physical state, water solubility, sulfur content, local conditions, previous exposures, and temprature. For instance with oil spill from IXTOC-1 oil well platform off coast of in Mexico, 50% evaporated, 25% sunk to the ocean bottom as a residue, 12% degraded by microbial and photochemical oxidation, 6% removed mechanically or burnt, 6% reached shore and contaminated Mexican shoreline and 1% reached beaches in Texas(1). The oil degradation can be seen in different levels including water surface, deeper waters, and sediments. Bacterial degradation, which called Biodegradation, can occur in each zone (2). After oil contamination the marine animals would damage most of all, e.g. after Torrey Canyon spill (1967) zooplankton community devasted, 90% of pilchard fish eggs destroyed, large number of young fish (fry) also died and some commercially important fish swallowed tar balls and were inedible and muscles of fish acquired a “petroleum taste”. There were some sign of decrease average size in some of limpets and effects on sea birds that emerge as disorders in their endocrine system, and eggs (1). Today based on the fact that biodegradation is the major process for removal of nonvolatile oil components from the environment, bioremediation has been proved to play important role in environmental cleanup. Some investigators have suggested adding specially selected hydrocarbon degrading bacteria (seeding) to enhance the rate of biodegradation in contaminated area (4). These bacteria use petroleum as carbon and energy source (that is essential for each organism) and produce biosurfactant during the procedure.Biosurfactants facilitate hydrocarbon uptake through the hydrophilic outer membrane. Many oil utilizing microorganisms produce cell-wall-associated or extra cellular surface active agents (6). Biosurfactant disperses the oil and facilitate its uptake by microbial cells. These metabolites have lower toxicity and high biodegradability (5).