Microbial Consortia and Biodegradation of Petroleum Hydrocarbons in Marine Environments

Abstract

The pollution of petroleum hydrocarbons in the sea is an increasingly widespread international problem that threatens the environment and human health. At present, there are important advances in relation to innovative and effective technologies for the elimination of oil contaminants from the marine environment. The main advantages of microbial remediation lie in its low cost and high efficiency in a sustainable manner. Numerous laboratory-scale studies and field application of microorganisms to clean up hydrocarbon-impacted marine and coastal environments have clearly demonstrated the viability of bioremediation technologies under various environmental conditions. In addition, due to the complex mixture represented by petroleum hydrocarbons, a consortium of taxonomically diverse species with broad enzymatic capabilities is required, because a single species can metabolize only a limited range of hydrocarbon substrates. Because, in natural environments, most of the microorganisms (>99%) coexist in the form of microbial consortia, there are major expectations on the uses of consortia of microorganisms to perform the degradation of complex molecules present in petroleum hydrocarbons. The members of the microbial communities acting together may exhibit the ability to secrete biosurfactants leading to the enhanced solubilization and removal of hydrophobic hydrocarbons. Recent reports have evidenced that halophilic bacteria and archaea have the capacity not only to cope with high-salinity stress but also be able to metabolize n-alkanes and PAHs suggesting their key role in mitigating vast areas of highly saline coastal habitats impacted by petroleum compounds that pose threat to both terrestrial and marine ecosystems. In this chapter, we report on recent developments on the biodegradation and bioremediation of petroleum hydrocarbons by microbial communities in marine and other high-salinity environments, and molecular mechanism of hydrocarbon degradation in halophiles has been described.