|Morrison Iii, Wiley|
|Rigsby, Luanne - Lowe|
Submitted to: Applied and Environmental Microbiology
Publication Type: Peer Reviewed Journal
Publication Acceptance Date: 2/1/1996
Publication Date: N/A
Interpretive Summary: Lignin in plant cell walls is the single most important limitation to microbial use of plant biomass. Research was undertaken to assess specific interactions of plants and fungi that selectively delignify plants and improve utilization. Results showed that specific interactions between crop and fungi occurred, and mechanisms which allowed significant improvement in biodegradation were identified.
Technical Abstract: Lignocelluloses from diverse plant types were treated with the white rot fungi Ceriporiopsis subvermispora (strains CZ-3-8497 and FP-90031-sp) and Cyathus stercoreus. Sources of lignocellulose included the warm-season grasses sorghum (leaf blades, sheaths, and stems), pearl millet, napiergrass, and maize (stems); the cool-season grass wheat (leaf blades, sheaths, and stems); and the legumes alfalfa (stems) and lespedeza leaflets and stems). Fungal-treated residues were compared with untreated , control samples and with plants treated with a non-delignifying isolate of Trichoderma. Residues were evaluated for improved biodegradability by ruminal microorganisms and modifications in cell wall chemistry by NMR, gas chromatography, and ultraviolet absorption microspectrophotometry. Specific plant/fungus interactions were identified that resulted in selective removal of lignin and improved biodegradability by white rot fungi but not the Trichoderma sp. All white rot fungi removed ester-linke p-coumaric and ferulic acids from grass stems, and this phenomenon appeared to account for the significant reduction in aromatic components and improved biodegradability of fungal-treated grass lignocellulose. Cell walls in alfalfa stems were more resistant to biological delignification than those in grasses, with only C. stercoreus removing significant amounts of aromatics and improving biodegradability. All white rot fungi improved the biodegradability of tannin-rich lespedeza samples.