Large quantities of toxic and intensely colored waste effluents are produced by a range of industrial processes. These effluents are treated by processes ranging from aerobic to anaerobic and physico-chemical techniques. More innovative technologies using white-rot fungi have also been studied (Kahmark and Unwin 1996). The use of microorganisms to detoxify environmental pollutants is generally referred to as bioremediation. Environmental issues are now of increasing concern and biological methods are being directed towards technologies to minimize pollution or remedy it if it occurs.
White-rot fungi and their ligninolytic enzymes appear to have wide industrial potential. Phanerochaete chrysosporium and Coriolus versicolor can degrade lignin and a number of related chlorinated compounds. They are also able to efficiently decolorize and dechlorinate such effluents (Archibald et al. 1990; Fukui et al. 1992; Sundmann et al. 1981). Efficient color removal from sulfite pulping effluents has also been observed with C. versicolor (Bergbauer et al. 1991; Royer et al. 1983). Furthermore, white-rot fungi are showing significant potential to biodegrade a large number of xenobiotic compounds and hazardous wastes (Field et al. 1993; Glaser 1990; Hammel 1989). Lignin peroxidase, manganese dependent peroxidase, and laccase are the three main ligninolytic enzymes (Leisola and Garcia 1989; Schoemaker et al. 1989) and have been well-studied but several other enzymes are involved in further degradation of the products resulting from their action.
This chapter describes the rationale and results for three related case studies using a white-rot fungus to (a) treat effluent wastewater to reduce color, (b) to decolorize dye solutions used in industrial processes, and (c) to determine the enzyme involved in the decolorization process.
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