As the demand for liquid petroleum increases, the need for reliable and efficient oil spill clean-up techniques is inevitable. Bioremediation is considered one of the most sustainable clean-up techniques but the potential has not been fully exploited in the field because it is too slow to meet the immediate demands of the environment. This study reviews the challenges to managing oil spills in terrestrial and marine environments to identify areas that require further research. Current challenges associated with bioremediation of spilled petroleum include resistance of asphalthenes to biodegradation; delay of heavy or high molar mass polycyclic aromatic hydrocarbon (PAH) biodegradation, eutrophication caused by biostimulation, unsustainability of bioaugmentation in the field, poor bioavailability of spilled petroleum, inefficiency of biodegradation in anoxic environments and failure of successful bioremediation laboratory studies in the field. Recommendations offered include encouraging asphalthene biodegradation by combining heat application (80°C), biosurfactant (thermophilic emulsifier) and bioaugmentation (using a consortium containing Bacillus lentus and Pleurotus tuberregium as members) but as a temporary measure, adopting the use of "booms and skimmers" and "organic sorbents" for water and land clean-up, respectively. Heavy PAHs may be rapidly degraded by applying nutrients (biostimulation) and biosurfactants to sites that are oleophilic microbe-rich. Oleophilic nutrients may be the most effective strategy to reduce eutrophication in marine environments whilst on land, slow-release nutrient application or organic-inorganic nutrient rotation may help prevent soil hardening and infertility. The use of encapsulating agents and genetically-engineered microbes (GEMs) may increase the efficiency of bioaugmentation in the field, but temporarily, indigenous oleophilic microbes may be employed in the field. Poor bioavailability of crude oil may be eliminated by the use of biosurfactants. In terrestrial anoxic sites, bioslurping-biosparging technology could be used whilst the marine anoxic site requires more research on how to transport nutrients and biosurfactants to oleophilic anaerobes residing in the ocean beds. The involvement of both governmental and non-governmental environmental institutions in sponsoring field studies in order to improve the reliability of bioremediation research. Further studies to test the practicability and cost of these recommendations in the field are needed.
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