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White-rot fungi have the ability to degrade lignin, a biopolymer in wood and woody plants which is resistant to attack by most microorganisms.1 Lignin is a complex, three-dimensional, nonrepeating polymer. White-rot fungi can degrade lignin using an extracellular, rather nonspecific, free-radical based biodegradation system.’ Because this degradation system can oxidize and reduce a wide variety of chemicals, it is rather nonspecific and can also degrade a wide variety of environmental pollutants 3,4 The degradation system is multicomponent, somewhat complex and unique, and somewhat redundant 3,5 That is, there may be more than one way to catalyze the same reaction or type of reaction,5 and there may be some very unusual ways to accomplish reactions through the involvement of chemicals produced by the fungi during secondary metabolism. The degradation of lignin occurs during secondary metabolism, when the fungi are limited in some nutrient.6–8 They obtain no energy from the degradation of lignin. The carbon substrate for the fungi is cellulose, but the fungi must degrade the surrounding lignin to gain access to the cellulose7 This seems to give these fungi the ability to degrade a wide variety of otherwise quite recalcitrant environmental pollutants3,4,9 or potential pollutants, including synthetic polymers.10 |
