Bioremediation is a process in which pollutants or contaminants in the environment are removed through the use of biological organisms or their products. The removal of these often hazardous pollutants is mostly carried out by naturally occurring or purposely introduced microorganisms that are capable of breaking down or absorbing the desired pollutant. The types of pollutants that are often the targets of bioremediation strategies are petroleum products (including oil and solvents) and pesticides. In addition to the microorganisms ability to digest and absorb the pollutants, their secreted exoenzymes play an important role in many bioremediation strategies.