中文摘要：

采用固定化洋葱假单胞菌脂肪酶（Pseudomonas cepacia lipase,PC脂肪酶）为催化剂,在有机溶剂体系中研究了环己烷二甲醇和环己烷二甲酸对聚丁二酸丁二醇酯（PBS）的改性共聚物,即聚（丁二酸丁二醇-co-丁二酸环己烷二甲醇酯）（PBS-co-CHDMS）和聚（丁二酸丁二醇-co-环己烷二甲酸丁二醇酯）（PBS-co-BCHDA）的降解规律及其差异性.通过共聚物降解率随时间的变化、降解产物的MALDI-TOF-MS分析研究了共聚物降解规律,并以分子模拟分别研究了降解差异性和PC脂肪酶与底物的结合机制.研究结果表明,PC脂肪酶均可催化PBS基共聚物降解;在降解60 h后,相比较于PBS-co-BCHDA,PBS-co-CHDMS降解率均更大;其中PBS-co-10%CHDMS降解率最大,为85%.共聚物降解不仅生成了线型小分子,还产生了部分环状低聚物;此外,PBS-co-CHDMS降解产生的低聚物种类比PBS-co-BCHDA的要多.分子对接模拟结果表明,在氯仿中,PC脂肪酶与底物结合自由能的大小顺序为CMSCM〉BSCM〉BCAB〉BSB,即含有丁二酸环己烷二甲醇酯（CHDMS）单元的底物与PC脂肪酶活性位点的对接更为稳定.

英文摘要：

The enzymatic degradation of poly（butylene succinate-co-1,4-cyclohexane dimethanol succinate） （PBS-co-CHDMS） , poly （ butylene succinate-co-butylene 1, 4-cyclohexanedicarboxylic acid ） （ PBS-co- BCHDA） and poly （butylene succinate） （PBS） were performed with the aim to gain more underlying information about the degradation rules and differences in organic solvent. Among various hydrolytic enzymes the lipase from Pseudomonas cepacia （PC） was chosen for the studies. The rules of enzymatic degradation were investigated by molecular weight variation and MALDI-TOF-MS analysis of the degradation products. Additionally, mechanism of the combination between substrate and enzyme was studied with molecular docking. The results indicated that PBS-based copolymers showed an obvious degradation in chloroform. Compared to PBS-co-BCHDA, PBS-co-CHDMSs all showed a greater degradation rate after 60 h enzymatic degradation. Particularly maximum degradation was observed in PBS-co-10% CHDMS with a degradation ratio of ratio about 85%. The enzymatic degradation of PBS-based copolymers produced not only linear segments, but also cyclic oligomers. Furthermore, PBS-co-CHDMS produced more oligomers than PBS-co-BCHDA. According to the results of molecular docking, the free energy of binding between PC lipase and substrate in chloroform was in the order of CMSCM 〉 BSCM 〉 BCAB 〉 BSB. That is,the docking of substrate containing 1, 4-cyclohexane dimethanol succinate（CHDMS） in the active site of PC lipase was more stable than any other ones.