具有温控自分离特性的高效纤维素酶解反应体系的构建与性能研究

In order to build sugar platform using cellulose as raw material, it is critical to realize the high efficient enzymolysis of cellulose and recycling of cellulase. To overcome the current shortcomings in the enzymolysis of cellulose, such as low efficiency, long reaction period, difficult to recycle the cellulase, high cost, etc. in this project, many new types of modifier with ethoxy units will be designed and synthesized; then new modified cellulase with temperature control phase separation characteristics are prepared by using new type modifier to bond with the thiol or amino of cellulase. According to the thermosensitivity of ethoxy and structure stability and high activity of modified cellulase, a novel system on enzymolysis of cellulose with temperature control phase separation characteristics will be formed. This system is based on NaOH/urea/water and realizes the high directional conversion of cellulose into reducing sugar. In addition, the relationship between the structure and property on the new modified cellulase will be studied, and the reaction mechanism and rules in the new reaction system will be explored. In conclusion, the modified cellulase can be easily recycled by its temperature control phase separation characteristics, and the research will provide a new efficient path to realize efficient utilization of cellulose and clean process of saccharification.

纤维素的高效酶解与纤维素酶的分离回收利用是建立以纤维素为原料经济高效制备葡萄糖的关键。本项目针对当前纤维素酶解过程存在的转化效率低、反应周期长、纤维素酶难以回收再用导致的成本高等固有缺陷，拟设计合成分子结构中带有乙氧基单元等温控基团的各种新型修饰剂，对纤维素酶的巯基或氨基进行定点修饰，创制出具有温控相分离特性的高活力新型纤维素酶。依据乙氧基基团的温控特性以及经修饰的纤维素酶结构稳定和活性高的特点，构建基于NaOH/尿素/水介质的具有温控自分离特性（高温均相酶解-低温两相分离）的新型纤维素酶解反应体系，将纤维素高效定向转化成还原糖。通过研究新型纤维素酶的结构与性能之间的关系，明确新反应体系的酶解及温控分离的本质规律和机制。利用经过修饰的纤维素酶所特有的温控自分离的特性，完成纤维素酶的分离回收再用，为实现纤维素的转化利用提供经济高效新途径。

纤维素的高效酶解与纤维素酶的分离回收利用是建立以纤维素为原料经济高效制备葡萄糖的关键。本项目针对当前纤维素酶解过程存在的转化效率低、反应周期长、纤维素酶难以回收再用导致的成本高等固有缺陷，设计合成了分子结构中带有乙氧基单元温控基团的七种新型修饰剂，分别对纤维素酶的巯基或氨基进行定点修饰，创制并筛选出两种具有温控相分离特性的高活力新型纤维素酶。依据乙氧基基团的温控特性以及经修饰的纤维素酶结构稳定和活性高的特点，构建了基于NaOH/尿素/水介质的具有温控自分离特性(高温均相酶解-低温 两相分离)的新型纤维素酶解反应体系，将纤维素高效定向转化成还原糖，与天然酶相比，修饰酶Cell-MAL 5K酶解纤维素得到的还原糖浓度大约是天然纤维素酶条件下的2倍。通过研究新型修饰纤维素酶的结构与性能之间的关系，明确新反应体系的酶解及温控分离的本质规律和机制。利用经过修饰的纤维素酶所特有的温控自分离的特性，完成纤维素酶的分离回收再用， 但回收酶的活性有待提高。