Marine hydrocarbon-degrading bacteria: their role and application in oil-spill response and enhanced oil recovery

Hydrocarbon-degrading bacteria in the oceans and seas occur in relatively low abundances, but they become enriched in the presence of hydrocarbons, such as during oil spills. Though some species, mainly those found in anoxic sediments, are capable of anaerobic degradation of hydrocarbons, most marine hydrocarbon-degrading bacteria are strictly aerobic. Those with an almost exclusive preference for hydrocarbons as a sole source of carbon and energy are the obligate hydrocarbon degraders—organisms that are fundamentally important in the natural purging of oil-polluted marine environments. One mechanism through which these bacteria degrade hydrocarbons is via their production of biosurfactants that reduce the interfacial tension between water and oil, and break up oil into small droplets, in turn making the oil more accessible to these bacteria for degradation. Hydrocarbon-degrading bacteria, and the biosurfactants they produce, have found enormous use in bioremediation and in enhanced oil recovery.