Biodegradation, or the transformation of chemical compounds by the action of living organisms, is one of the major processes that determines the fate of organic chemicals in aquatic and terrestrial environments. Microorganisms play a major role in biodégradation because of their abundance, species diversity, catabolic versatility, high metabolic activity, and their ability to adapt to a wide variety of environmental conditions. Furthermore, microbial degradation is unique in contrast to nonbiological processes, such as hydrolysis or photochemical degradation, in that mineralization, or the complete conversion of organic compounds to inorganic products, is almost always due to microbial activity.’