ISSN:
1432-5225
Source:
Springer Online Journal Archives 1860-2000
Topics:
Agriculture, Forestry, Horticulture, Fishery, Domestic Science, Nutrition
,
Mechanical Engineering, Materials Science, Production Engineering, Mining and Metallurgy, Traffic Engineering, Precision Mechanics
Notes:
Summary Samples of non-decayed birch wood and samples decayed to weight losses of 21, 44, and 67% by Coriolus versicolor were subjected to acidolysis (4h reflux in dioxane-water, 9:1 by volume, containing 0.2 M HCl). The yields of the two major products, 3-hydroxy-1-(4-hydroxy-3-methoxyphenyl)-2-propanone (ketol I) and 3-hydroxy-1-(4-hydroxy-3,5-dimethoxyphenyl)-2-propanone (ketol II), as a percentage of residual lignins, decreased progressively with increasing decay. Even so, substantial yields of I and II were obtained from the decayed wood, suggesting that during decay a considerable amount of the lignin remaining in the wood was as yet unaltered (e. g. ∼50% at a 67% weight loss). This result indicates that lignin is degraded from exposed surfaces; the decreasing yields of I and II with decay show that the surfaces become progressively larger. The more rapid decrease in the yield of ketol II than in the yield of ketol I indicates that syringyl elements were degraded more rapidly than guaiacyl elements. The fungal enzymes, acting progressively from the lumen surfaces toward the middle lamella, encountered syringylrich lignin first.
Type of Medium:
Electronic Resource
URL:
http://dx.doi.org/10.1007/BF00353387
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