白腐菌Panus conchatus降解稻草木素机理研究──(三)木素降解产物低分子部分芳香酸类化合物的结构特征

利用色-质联用技术分析了稻草木素经由腐菌Panusconhatus生物作用后的木素降解产物中低分子酸性组分的主要化合物及其结构。结果表明此组分中大部分是芳香族化合物，通过质谱对其主要的11种化合物的结构进行了分析，发现它们主要成分是紫丁香酸，香草酸和对羟基苯甲酸及其衍生物，证实木亲生物降解过程发生木余例键Cα-Cβ键氧化断裂；另外，发现其中有相当数量的对羟基苯甲酸衍生物具有缩聚型结构，它们来源于木素结构中“核心”结构部分。根据各个化合物的相对含量计算出愈钢木基：紫丁香基：对羟基本基比例为6．1：1：2．7。证实木亲生物降解过程中本素的愈疮木基与对羟苯基结构单元优先降解，这结果与过去有关电镜和木素降解产物高分子部分的研究结果是一致的。

Investigations related to biodegradation of lignin in rice straw by Panus conchatus──Ⅲ.Characterization of aromatic acids in low-molecular-weight fraction of the lignin degradation products

Main constituents of low molecular weiht acideic fraction frm rice straw decayed by awhite rot fungus.P.conchatus were investigated by GC and GC-MS analyses.The results demon-strated that most of constituents in ths fraction were aromatic compunds,resulting in identifica-tion of 11 aromatic acids derived from fungal degradation of rice straw lignin.Vaillic,syringic,and p-hydroxy-benzonic acids and their derivatives were the major constiturnts of the fraction.Tus,the results indicated that oxidative cleavage of Ca-Cb bond occurred during the process of lignin biodegration.We also found that some p -hydroxy-benzonic acid derivatives originatedcondensed structure of lignin core,not peripheral group.The ration of guaiacyl,syringic and p-hy-droxy-benzonic type substructures in the constituents was 6.1:1:2.7 The result innndicated thatlignins with guaiacyl and p-hydroxy -benzonic substructures in rice straw sere degraded pre-dominantly and was in accordance with our previous results obtaines by electromicroscopy.Demethylation was also found during the process of lignin biodegradation.