绿色糖单孢菌复合胞外酶纸浆漂白效果及机理研究（作者张勇，导师.doc

绿色糖单孢菌复合胞外酶纸浆漂白效果及机理研究 （作者：张勇，导师：蒲俊文教授谢响明副教授种酶直接进行协同生物漂白的研究目前还未见报道。国际上对白腐菌胞外酶纸浆生物漂白的研究已取得一定进展，但真菌胞外酶对热稳定性不高，最适pH值一般在酸性范围内。为适应碱法化学浆碱性、高温条件，目前发展趋势是寻找并采用耐热嗜碱性的复合胞外酶对纸浆进行生物漂白放线菌来源的绿色糖单孢菌，可产生同时含有木聚糖酶和木素过氧化物酶的复合胞外酶，无需人工复配即可对纸浆中的木聚糖和木素进行降解，经实验证明其在较高温度和pH值范围内表现出稳定活性，对纸浆生物漂白具有独特的优势和潜力。mechanism of compound enzyme from Saccharomonospora viridis bleaching pulps （Zhang Yong Directed by Prof.Pu Jumwen Adjunct Prof.Xie Xiangming） residual lignin in it. In the traditional pulp bleaching process, chlorine bleaching agent is used to remove the lignin or change the structure of lignin chromophoric group in the pulp. Because the cheap chlorine bleaching agent could react with the phenol-type and non-phenol-type structure of the lignin directly, it has been using widely in the field of pulp bleaching for a long time. But the effluent of the chlorine bleaching, which contains carcinogenic and abiding organic chloride like dioxin, is polluting the environment seriously. Therefore, it is necessary to improve the traditional pulp bleaching from the biological process. Enzyme bleaching is the process of using the extracellular enzyme secreted by microorganism to remove the lignin in the pulp. The common enzymes are xylanase, lignin peroxidase and laccase. The technique of xylanase aid-bleaching has been industrialized and the main purpose of this technique is degrading the xylan in the fibre cell wall or on the fibre surface. Thus, with the enhancement of fibre permeability the following chemical bleaching agent could permeate into the internal fibre to degrade lignin. Lignin peroxidase is a kind of high selectivity lignin degrading enzyme and could destroy a series of lignin chromophoric and aid-chromophoric groups. At present, most studies usually use one kind of enzyme to bleach pulp, it is singular to use two even more kinds of enzymes to bleach cooperatively. According to the lastest research, synergetic bleaching consisted of xylanase and lignin peroxidase could remove the xylan, lig