Introduction

Environmental pollutants are a serious concern worldwide because of the hazards they pose to the health of humans and animals. An estimated 80 billion pounds of hazardous organopollutants are produced annually by the chemical, agricultural, oil, paper, textile, aerospace, and other industries in the USA alone (Aust, 1990). Only about 10% of these wastes are believed to be disposed of in an environmentally safe manner (EPA, 1988; Fernando & Aust, 1994). Traditional methods of disposing of hazardous wastes (physical, chemical, and thermal treatments and land filling) have not always been efficacious. It has been estimated that it costs about one trillion dollars to decontaminate toxic waste sites in the USA alone using traditional waste disposal methods (Barr & Aust, 1994). Considering these staggering costs for cleaning up the environment, an alternative, rapid, efficacious and cost-effective method is needed. One method that has become increasingly popular for decontamination of the environment has been bioremediation. The use of indigenous or suitable introduced microorganisms at contamination sites often provides an efficient and economically attractive solution to the pollution problem. One of the early reports indicated that lignin-degrading white rot fungi, as exemplified by Phanerochaete chrysosporium, can degrade an extremely diverse group of environmental pollutants (Bumpus et al., 1985). Since then, there has been intense worldwide research to unravel the potential of white rot fungi in bioremediation. This ability of white rot fungi to degrade a wide spectrum of environmental pollutants sets them apart from many other microbes used in bioremediation.