English: General overview of microbial biodegradation of petroleum oil by microbial communities. Some microorganisms, such as A. borkumensis, are able to use hydrocarbons as their source for carbon in metabolism. They are able to oxidize the environmentally harmful hydrocarbons while producing harmless products, following the general equation CnHn + O2 H2O + CO2. In the figure, carbon is represented as yellow circles, oxygen as pink circles, and hydrogen as blue circles. This type of special metabolism allows these microbes to thrive in areas affected by oil spills and are important in the elimination of environmental pollutants.