Extracellular degradation of polyethers by the brown rot fungus Gloeophyllum trabeum

Brown rot fungi are uniquely able to decay wood by selectively degrading its cellulose. Their ability to depolymerize crystalline cellulose and to penetrate the recalcitrant lignin barrier in wood suggests the involvement of low molecular weight diffusible agents, for example iron-binding compounds that might carry out one-electron oxidation reactions. We found that cultures of the brown rot fungus Gloeophyllum trabeum effkiently degraded U-[ 14C]cellulose synthetic methoxyl-[ 14C]lignin and l-[ 14C]L-glucose to 1602. The fungus also depolymerized and mineralized poly-ethyleneglyco1) (PE’G), a biologically recalcitrant polymer. The degradation of polyethers by G. trabeum probably reflects the operation of nonspecific extracellular oxidants. These oxidants could contribute to the depolymerization of crystalline cellulose in the fungal natural habitat.