Polycyclic aromatic hydrocarbons (PAHs) are a group of contaminants mainly derived from natural gas and petroleum. Due to their stable ring structures, poor water solubility and chemical stability, these contaminants are difficult to degrade and persist for long time in the environment, where they pose a hazard to the environment and human health. The enormous concern about PAHs-contamination lies on the fact that high percent of human activities depend on petroleum, not only as fuels for transportation but also for the production of asphalt, plastics, synthetic fibers, lubricants, detergents and fertilizers. Petroleum extraction and refining activities result in PAHs discharge to the environment. Among PAHs-remediation methods is biodegradation of these compounds by the activity of microorganisms. Many bacteria are capable of using PAHs as a source of carbon and energy, as part of a metabolism that also relies in oxygen. However, saturated PAH-contaminated sites rapidly become anoxic, and microorganisms able to use these compounds as a carbon source in the absence of oxygen are crucial for their degradation. So far, information about the responsible organisms or the mechanisms for PAHs degradation in the absence of molecular oxygen are very scarce. The overall aim of the PrOBiEM project is to elucidate the mechanisms for the anaerobic degradation of phenanthrene by a bacterial enrichment culture (TRIP) obtained from a natural asphalt lake. Specifically, to identify enzymes involved in the degradation of this PAH, which is composed by three benzene rings. Phenanthrene is an EPA (United States Environmental Protection Agency) Priority Pollutant and is a major component of the total content of PAH compounds in the environment.
