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

为了阐明碳水化合物组分在木质素生物降解中的作用，对木质素模型化合物和DHP木质素的转化进行了研究。研究结果如下：(1)腐木真菌（Phanerochaete chrysosporium、corolus versicolor和Tyromyces palustris）对木质素模型化合物（4-乙基丁香基甘油- -丁香基醚、戊醇、香草醇和戊醛）的消耗速率取决于碳水化合物介质的种类。模型化合物的消耗速率顺序为：多糖培养基（木聚糖、全纤维素）、双糖培养基（纤维素二糖）、单糖培养基（葡萄糖、木糖）。(2)在多糖和双糖培养基中，模型化合物通过碳水化合物诱导糖苷酶与腐木真菌的转糖化作用转化为其糖苷。在木聚糖和桦木全纤维素培养基中，戊曲醇在培养初期转化为戊曲醇- d -木糖苷。在纤维素二糖培养基中，香草醇和戊曲醇分别转化为香草基- d -葡萄糖苷和戊曲基- d -葡萄糖苷。(3)木质素模型化合物对真菌的毒性通过其糖苷的形成而降低。漆酶或木质素过氧化物酶对酚类模型化合物的聚合反应因其糖苷的形成而减少。(4)采用酶法合成DNP木质素-葡萄糖苷。木质素过氧化物酶/ H_2O_2对DHP木质素-葡萄糖苷的影响是部分解聚，而对DHP木质素的处理是部分聚合。

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.