BIOLOGICAL DELIGNIFICATION OF PLANT-COMPONENTS BY THE WHITE-ROT FUNGICERIPORIOPSIS-SUBVERMISPORA AND CYATHUS-STERCOREUS

Lignocelluloses from diverse plant types were treated with the white r ot fungi Ceriporiopsis subvermispora (strains CZ-3-8497 and FP-90031-s p) and Cyathus stercoreus. Sources of lignocellulose included: the war m-season grasses sorghum (leaf blades, sheaths, and stems), pearl mill et, napiergrass, and maize (stems); the cool-season grass wheat (leaf blades, sheaths, and stems); the legumes alfalfa (stems) and lespedeza (leaflets and stems). Fungus-treated residues were compared with untr eated, control samples and with plants treated with a non-delignifying isolate of Trichoderma, Residues were evaluated for improved biodegra dability by ruminal microorganisms and modifications in cell wall chem istry by nuclear magnetic resonance, gas chromatography, and ultraviol et absorption microspectrophotometry. Specific plant-fungus interactio ns were identified that resulted in selective removal of lignin and im proved biodegradability by white rot fungi but not the Trichoderma sp. All white rot fungi removed ester-linked p-coumaric and ferulic acids from grass stems, and this phenomenon appeared to account for the sig nificant reduction in aromatic components and improved biodegradabilit y of fungus-treated grass lignocellulose. Cell walls in alfalfa stems were more resistant to biological delignification than those in grasse s, with only C. stercoreus removing significant amounts of aromatics a nd improving biodegradability. All white rot fungi improved the biodeg radability of tannin-rich lespedeza samples.