木素—碳水化合物复合体的化学结构及其生物降解机理

A part of lignin in fiber material and unbleached pulp associates with chemical linkage to form lignin- carbohydrate complexes (LCC). The existence of LCC inhibits the dissolution of lignin during pulping and bleaching process and consumes much chemicals and energy. This will cause serious environmental pollution. Therefore, the research on the cleavage of LCC bond selectively is very important in order to develop less pollution technique in pulping and bleaching processes. With the use of carbon-13 isotopic tracer method combined with high resolution NMR analysis technique, it was found that coniferin has an important role in the biosynthesis of Licit was also proved that benzyl ether linkage、ester linkage and ketal linkage at a-position of lignin side chain were main types of LCC bond。 The chemical linkages between lignin macromolecular and carbohydrates were illustrated by this method. Furthermore, it was proved that chemical linkage could be formed between dehydrogenated polymer (DHP) and hemicelluloses or cellulose with the use of lignin peroxidase etc. as catalyzers. On the basis, the mechanism of laccase-based biomimetic treatment (Cu2+/ Pyridine/ H2O2) of LCC, milled wood lignin and lignin model compound was investigated. It was found that the biomimetic could degrade residual lignin as LCC, phenolic and non-phenolic type lignin. Biomimetic bleaching of Kraft pulp was also explored. It was found that this bleaching system had very strong ability in degradation of residual lignin in pulp. These results will lead to the development of novel and less pollution bleaching technologies.

采用处源性同位素标记法对木素—碳水化合物复合体中苯丙烷结构单元的侧链碳原子进行选择性碳—１３标记，用核磁共振法（碳谱）对经标记的新生木质部和未漂纸浆中木素和碳水化合物之间的连接键进行定性和定量分析，阐明木素—碳水化合物复合体的结构。深入研究各类连接键在生物降解过程中的变化规律，为建立新一代纸浆生物漂白技术提供理论指导。