Isolation of lignin-carbohydrate bonds in wood

木粉中约96%的木质素经20倍臭氧氧化16h后，降解为分子量很小的木质素，不能生成酸不溶性木质素。另一方面，LCC产品，其中包含一个苄基醚型LCC键的分子中分离后，臭氧化和酸水解的红松木材。阴离子交换层析后的酸性组分中含有LCC产物，酸性组分是木质素中的有机酸和多糖中的酸性糖的混合物。三甲基硅烷化后的产物在气相色谱上的保留时间与LCC产物相似，LCC产物的鉴定非常困难。但是，乙酰化后，而不是三甲基硅烷化后，它得到了改善。从葡萄糖和甘露糖键合的LCC模型化合物中分离到LCC产物，并且从红松木材中也分离到一些在GC色谱图上与这些LCC产物具有相同保留时间的产物。这些产物在总离子色谱图上的保留时间与LCC模型化合物中的LCC产物相同，质量碎片模式也相似。因此，这些结果表明，苄基醚型LCC键之间的木质素和己糖，如葡萄糖和甘露糖，分离从红松木材通过臭氧化和酸水解没有LCC键断裂。

Mostly lignin, it is about 96% lignin in wood meal, was degraded to very low molecular weight structures which could not give acid insoluble lignin after ozonation for 16 hours with 20 times molar ozone. On the other hand, LCC products which contain a benzyl ether type LCC bond in a molecular were isolated from red pine wood after ozonation followed by acid hydrolysis. LCC products were included in the Acidic fraction after anion exchange chromatography, the Acidic fraction was mixture of many products such as organic acids from lignin and acidic sugars from polysaccharides. Many products gave similar retention time compare with that of LCC products on GC chromatogram after trimethylsilylation, identification of LCC products was very difficult. However, it was improved after acetylation instead of trimethylsilylation. LCC products were isolated from both glucose and mannose bonded LCC model compounds and some products which give same retention time on GC chromatogram with these LCC products were also isolated from red pine wood. These products isolated from red pine wood gave same retention time on total ion chromatogram and showed similar mass fragment pattern, compared with LCC products isolated from LCC model compounds. Therefore, these results suggested that benzyl ether type LCC bonds between lignin and hexoses, such as glucose and mannose, were isolated from red pine wood by ozonation followed acid hydrolysis without LCC bond cleavage.