|Associate Professor of Bacteriology|
|1 Gifford Pinchot Drive|
|Phone: (608) 231-9528|
We have shown that diverse fungal systems for lignocellulose degradation share a unifying feature: they use extracellular one-electron chemistry to oxidize target molecules to unstable free radicals, which subsequently undergo oxygenation or decomposition. Although these mechanisms are intended to work on lignocellulose, they are so nonspecific that they also accomplish a wide variety of xenobiotic oxidations.
For example, we find that the wood decay basidiomycete Gloeophyllum trabeum degrades recalcitrant polymers with oxidants that are generated via quinone redox cycling. This fungus produces the metabolite 2,5-dimethoxy-1,4-benzoquinone, reduces it with an intracellular NADH-linked flavoprotein reductase, and releases the resulting hydroquinone into the extracellular medium. The hydroquinone then reacts non-enzymatically with extracellular Fe3+ to generate radical oxidants. Detailed characterization of the reductase and the gene that encodes it is now complete.