为了满足日益严格的AOX排放标准，制浆造纸企业采取了很多方法改进漂白技术，以木聚糖酶为主的生物酶辅助漂白是目前纸浆清洁化漂白的首选技术之一，但木聚糖酶辅助二氧化氯漂白过程AOX生物减量作用机制目前尚不清楚，深入挖掘AOX生成机理并从源头控制AOX的产生，成为当今纸浆清洁化漂白亟待解决的问题。本项目拟通过探索木聚糖酶辅助二氧化氯漂白过程AOX生成规律，构建漂白过程纸浆中己烯糖醛酸（HexA）降解动力学模型。重点研究了木聚糖酶预处理对HexA的脱除和二氧化氯减量效果的影响、酶处理对纤维的作用机制及HexA对AOX生成量的影响，结合量子化学中分子模拟技术，分析HexA与二氧化氯反应生成AOX的中间过程，阐明了木聚糖酶预处理减少AOX生成的机理。研究成果对于纸浆漂白过程控制AOX生成，实现纸浆清洁化漂白具有重大意义，将有助于解决我国木聚糖酶辅助漂白的工业化应用问题，进一步提高纸浆生物漂白技术水平。

Paper mills never stop improving the bleaching process to meet the increasingly stringent adsorbable organic halides (AOX) emissions standards. Xylanase-based enzymes aided bleaching is one of the preferred technologies at present. It is not clear that how xylanase could reduce AOX formation during the xylanase aided chlorine dioxide bleaching. In-depth study of AOX formation mechanism and controlling the AOX formation at the beginning of bleaching become an urgent problem need to be solved today. This proposal intends to study the AOX formation regularity during xylanase aided chlorine dioxide bleaching. Hexenuronic acid (HexA) degradation kinetics models will be established during the xylanase pretreatment and chlorine dioxide bleaching. It will mainly study the removal of HexA and reduction of chlorine dioxide by xylanase pretreatment, the enzyme action mechanism on fiber and the contribution of AOX formation by HexA. The reaction intermediates and pathway will be calculated using molecular modeling techniques, and AOX formation mechanism will thus be derived. The research achievement will have a great significance on controlling of AOX formation and realizing clean bleaching. It will help to solve the problems of the industrialized application of xylanase aided bleaching, and further improve the pulp bleaching technology level.