The Role of Glycosides Formation on the Degradation of Lignin by Wood-Rotting Fungi.

为了阐明碳水化合物在木材木质素生物降解中的作用，研究了木质素模型化合物和DHP木质素的转化。结果表明：(1)(1)木腐菌(黄孢原毛平革菌、杂色云芝和沼泽酪霉)对起始木素模型化合物(4-乙基丁香甘油-丁香醚、藜芦醇、香草醇和藜芦醛)的消耗速率取决于碳水化合物的种类。模型化合物的消耗率顺序为：多糖(木聚糖、综纤维素)双糖(纤维二糖)单糖(葡萄糖、木糖)。(2)在多糖和双糖介质中，通过糖苷酶与木腐菌的糖苷化作用，将模型化合物转化为糖苷类化合物。在木聚糖和桦木全纤维素培养的早期阶段，藜芦醇被转化为藜芦醇-D-木糖苷。在纤维二糖介质中，香草醇和藜芦醇分别被生物转化为香草基-D-葡萄糖苷和藜芦基-D-葡萄糖苷。(3)木质素模型化合物通过糖苷的形成降低了对真菌的毒性。漆酶或木质素过氧化物酶催化酚类模型化合物的聚合反应是通过糖苷的形成来减少的。(4)采用酶法制备了DNP木质素-葡萄糖苷。DHP木质素-葡萄糖苷与木质素过氧化物酶/H_2O_2共孵育可导致部分解聚，而DHP木质素与木质素过氧化物酶/H_2O_2共处理可引起部分解聚。

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.