乳果糖是乳糖的结构异构体，具有重要的健康生理功效。纤维二糖差向异构酶（CEase）能催化乳糖进行构造异构化与差向异构化反应。已知的CEase存在热稳定性不足和构造异构化选择性较差的问题，阻碍了其在乳果糖工业生产中的应用。文献及前期研究表明，以筛选压力驱动的定向进化策略和以数据分析驱动的计算机辅助手段能帮助优化工业酶的催化属性。鉴于此，本课题拟整合生物信息学、分子动力学模拟与高通量筛选等技术，分别针对CEase的热稳定性与构造异构化选择性进行酶的开发与改造。主要内容为通过理性挖掘与改造的方式获取高热稳定性的CEase野生型酶及突变体酶；阐明CEase的构造异构化催化机理，优化CEase的构造异构化选择性；最终，归纳稳定性与反应选择性改造的成果，实现CEase产乳果糖能力的提升。本项目的实施在CEase及同类型工业酶的理性开发与工业化应用领域将具有重要的科学与实践意义。

Lactulose is an isomer of lactose. It has important health-related physiological effects. Cellobiose 2-epimerase (CEase) can catalyze isomerization and epimerization reactions of lactose. Currently, the thermostability and isomerization selectivity of CEase are relatively low, which hamper its application in the industrial production of lactulose. Literatures and our previous studies have shown that directed evolution driven by the selective pressure and computer-assisted method driven by data analysis can help to optimize the catalytic properties of industrial enzymes. Therefore, the technologies including bioinformatics, molecular dynamics simulation and high-throughput screening will be integrated to develop and modify the thermostability and isomerization selectivity of CEases. The wildtype and variant CEases with high thermostability will be obtained by rational exploration and modification in this project; The isomerization mechanism of CEase will be illustrated to improve the isomerization selectivity of CEase; Finally, the result of the modifications on thermostability and reaction selectivity will be summed up to increase the lactulose productivity of CEase. The implementation of this project will be scientifically and practically significant to rational development and industrial application of CEase and the same type of industrial enzymes.