Bacteria play a major role in the elimination of persistent organic pollutants, through specific degradation enzymes. This is the case for the Sphingomonas CHY-1 species that degraded polycyclic aromatic hydrocarbons (PAHs). Of this bacterium, researchers from our laboratory have purified and characterized a dioxygenase that catalyzes the initial step of PAHs oxidation. This is a three components metalloenzyme witch catalytic unit contains a [2Fe-2S] cluster and a ferrous iron atom per subunit.