Organopollutant degradation by wood decay basidiomycetes

Ligninolytic 'white-rot fungi’ degrade a wide range of organopollutants such as polycyclic aromatic hydrocarbons (PAHs), pharmaceuticals, pentachlorophenol (PCP), pesticides, and explosives. Unique and powerful extracellular oxidizing systems, as well as intracellular metabolic processes, have been repeatedly invoked to explain the extraordinary oxidation potential of these microbes, but the precise mechanisms remain elusive. Recent advances in the biochemistry and genomics of white-rot fungi have increased knowledge and understanding of both lignin and organopollutant metabolism. In this chapter, we review the biochemistry of lignin peroxidase, manganese peroxidase, laccase, peroxide generation and other oxidoreductases such as cytochrome P450s. Comparative genome analysis of gene families encoding these enzymes is described with emphasis on gene structure, phylogeny, and expression. Ultimately, increasing genome resources will elucidate mechanisms of ligninolysis and simultaneously serve as a framework for development of effective bioremediation and related bioprocesses.