锰过氧化物酶催化偶氮染料降解的产物分析及酶分子修饰改造

酶促催化污染物的降解为我们提供了实现绿色工艺的途径和希望。然而，由于染料结构复杂，生物降解的程度及其生物毒性未能引起足够重视。前期研究发现乳白耙齿菌（Irpex lacteus F17）产生的胞外锰过氧化物酶（MnP）与白腐真菌模式种黄孢原毛平革菌（Phanerochaete chrysosporium）的MnP具有明显的结构和氨基酸序列及成熟蛋白长度的差异，且该酶表现了良好的染料脱色性能。因此，本项目在前期工作基础上，注重研究偶氮染料脱色降解的化学转化过程，分析其降解产物以及产物的生物毒性。同时，根据该酶催化反应的特点和其分子结构，选择理想的突变位点，将理性突变技术与化学修饰相结合对酶分子进行有目的地改造，提高酶的催化活性和稳定性能，以获得具有应用价值的新MnP酶，达到更高效率地降解污染物、产物无害化的目的。因此，本项目无疑将会促进生物降解研究的深化，为污染物的治理提供理论和技术支撑。

The degradation of the environmental pollutants by the enzymatic action provides us possibilities and methods to fulfill green technology. However, due to the complex structure of the synthetic dyes, the levels of these compounds degradation and biotoxicity of their degradation products have not yet raised enough attention. It has been discovered by our previous researches that the MnP of Irpex lacteus F17 differs significantly from the MnP of the archetypal white-rot fungus Phanerochaete chrysosporium in their molecular structure and amino-acid sequences, as well as mature protein lengths. Besides, the decolorization capability of the Irpex lacteus F17 has been proven to be remarkable. Therefore, this project, based on former work, emphasizes on the study of chemical conversion of azo dyes during the degradation process and further on the analysis of their degradation products and their biotoxicity. Meanwhile, with respect to catalytic properties and molecular structure of the MnP, desired mutation sites are chosen, and molecular engineering of the enzyme are carried out purposefully in order to improve enzymatic activity and stability by the use of chemical modification and rational mutation technology, and to acquire new usable MnP for more effective pollutants degradation and innoxious products. Consequently, this project would ,undoubtfully, deepen the study of biodegradation and provide theoretical and technical support for effective pollutant treatment.