Changes in structural and chemical components of wood delignified by fungi
Cerrena unicolor, Ganoderma applanatum, Ischnoderma resinosum and Poria medulla-panis were associated with birch (Betula papyrifera) wood that had been selectively delignified in the forest. Preferential lignin degradation was not uniformly distributed throughout the decayed wood. A typical white rot causing a simultaneous removal of all cell wall components was also present. In the delignified wood, 95 to 98% of the lignin was removed as well as substantial amounts of hemicelluloses. Scanning and transmission electron microscopy were used to identify the micromorphological and ultrastructural changes that occurred in the cells during degradation. In delignified areas the compound middle lamella was extensively degraded causing a defibration of cells. The secondary wall, especially the S2 layer, remained relatively unaltered. In simultaneously white-rotted wood all cell wall layers were progressively removed from the lumen toward the middle lamella causing erosion troughs or holes to form. Large voids filled with fungal mycelia resulted from a coalition of degraded areas. Birch wood decayed in laboratory soil-block tests was also intermittently delignified, selective delignification, sparsely distributed throughout the wood, and a simultaneous rot resulting in the removal of all cell wall components were evident. SEM appears to be an appropriate technique for examining selectively delignified decayed wood. 30 references.
- Research Organization:
- Univ. of Minnesota, St. Paul
- OSTI ID:
- 5063698
- Journal Information:
- Wood Sci. Technol.; (United States), Vol. 19:1
- Country of Publication:
- United States
- Language:
- English
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Related Subjects
59 BASIC BIOLOGICAL SCIENCES
BIRCHES
DELIGNIFICATION
WOOD
MORPHOLOGICAL CHANGES
BIODEGRADATION
CHEMICAL COMPOSITION
ELECTRON MICROSCOPY
FUNGI
HEMICELLULOSE
LIGNIN
STRUCTURAL CHEMICAL ANALYSIS
CARBOHYDRATES
CHEMICAL REACTIONS
DECOMPOSITION
MICROSCOPY
ORGANIC COMPOUNDS
PLANTS
POLYSACCHARIDES
SACCHARIDES
TREES
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