Microbial remediation of organometals and oil hydrocarbons in the marine environment

Marine environments are exposed to pollution that mostly results from human activities. Organometals and oil hydrocarbons are among the most hazardous pollutants. In surface waters and along the water column, these compounds are more easily degraded than in sediments, especially under anoxic conditions, where they are highly persistent. Due to their negative impact in living organisms, decontamination of polluted marine sites with minimum collateral impacts is imperative. Bioremediation strategies, benefiting from the ability of aerobic and anaerobic microorganisms to degrade organometals or oil hydrocarbons to simpler and less toxic derivatives, represent an alternative to traditional physicochemical decontamination methods. Different bioremediation strategies have been applied in marine environments, including monitored natural recovery, biostimulation, bioaugmentation and phytoremediation. Individual microbial agents or mixed microbial consortia able to remediate these pollutants in marine environments have been identified, and the most relevant mechanisms of biodegradation of pollutants are characterised. This chapter provides an overview on microbial bioremediation of organometals and oil hydrocarbons in marine environments, focusing on the bioremediation concept, microbial aerobic/anaerobic agents, metabolic pathways and genetic determinants involved in the degradation/transformation processes while highlighting the importance of microbial consortia and their applications. A critical analysis of the advantages and limitations of microbial remediation and a perspective on future developments are also provided.