| Budget Amount *help |
¥1,700,000 (Direct Cost: ¥1,700,000)
Fiscal Year 1988: ¥600,000 (Direct Cost: ¥600,000)
Fiscal Year 1987: ¥1,100,000 (Direct Cost: ¥1,100,000)
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| Research Abstract |
In order to clarify the role of carbohydrates components on the biodegradation of lignin in wood, the transformation of lignin model compounds and DHP lignin was studied. The results are as follows;(1)
(1) The rate of the consumption of the starting lignin model compounds (4-ethylsyringylglycerol- -syringyl ether, veratryl alcohol, vanillyl alcohol and veratrum aldehyde) by wood-rotting fungi (Phanerochaete chrysosporium, Coriolus versicolor and Tyromyces palustris) dependedon the kind of carbohydrate media. The order of the rate of the modelcompounds consumption was, polysaccharide medium(xylan, holocellulose) disaccharide medium (cellobiose ) monosaccharide medium (glucose,xylose).
(2) In the polysaccharide and the disaccharide medium, model compounds were transformed into their glycosides by the transglycosy-lation of glycosidase induced by carbohydrates with wood-rotting fungi. In the xylan and birch holocellulose medium, veratryl alcohol was transformed into veratryl -D-xyloside during the early phase of cultivation. In the cellobiose medium, vanillyl alcohol and veratryl alcohol were biotransformed into vanillyl -D-glucoside and veratryl -D-glucoside, respectively.
(3) The toxicity of lignin model compounds against fungus was reduced by the formation of their glycosides. The polymerization of phenolic model compounds by laccaseor lignin peroxidase was reduced by the formation of their glycosides.
(4) DNP lignin-glucoside was synthesized by an enzymatic method. Incubation of DHP lignin-glucoside with lignin peroxidase / H_2O_2 resulted in partial depolymerization, although treatment of DHP ligninwith them caused polymerization.
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