The white rot fungus Phanerochaete chrysosporium is able to degrade lignin, a structurally complex, naturally occurring and environmentally persistent, non-repeating heteropolymer. Previous studies have shown that this fungus is also able to degrade a wide variety of synthetic organopollutants and that biodegradation is dependent, at least in part, on the lignin degrading system. Examples of recalcitrant chemicals that are degraded to carbon dioxide by this fungus include tetrachlorobiphenyl hexachlorobiphenyl, tetrachlorodibenzo(p)dioxin. A number of these compounds were selected for further study to more thoroughly document biodegradation. Using Chlordane and pentachlorophenol it was shown that, like lignin, mineralization of these two environmentally persistent xenobiotics was promoted in nutrient nitrogen deficient cultures while mineralization was suppressed in nutrient nitrogen sufficient cultures.