College of Environmental Science and Engineering, Shaanxi University of Science & Technology, Xi'an 710021, China; Shaanxi Research Institute of Agriculture Products Processing Technology, Xi'an 710021, China.
College of Environmental Science and Engineering, Shaanxi University of Science & Technology, Xi'an 710021, China.
Int J Biol Macromol. 2018 Oct 15;118(Pt A):347-356. doi: 10.1016/j.ijbiomac.2018.06.062. Epub 2018 Jun 20.
The difference of enzymatic degradation behavior between Poly (butylene succinate-co-diethylene glycol succinate) (PBS-co-DEGS) and Poly (butylene succinate-co-butylene diglycolic acid) (PBS-co-BDGA) was studied in a Tetrahydrofuran (THF)/toluene mixed system by Novozym 435 (N435, immobilized Candida Antarctica lipase supported on acrylic resin) catalysis for 30 h. These two copolymers (modified with alcoholic acid by ether linkage) were synthesized by melt polycondensation and characterized by H NMR. The average molecular weight and thermal property before and after degradation were determined by gel permeation chromatography (GPC) and thermogravimetric analysis (TGA), respectively. Results revealed that end-chain degradation of DEG20 (20% content diethylene glycol of diols) and intramolecular random degradation of DGA20 (20% content diglycolic acid of diacids) both occurred at the same time from 0 h to 12 h. TGA curves show that after degradation by N435, the T-5% of both copolymers decreased from about 300 °C to below 210 °C. In degradation products (linear and cyclic oligomers, no monomer was appeared below 10 degree of polymerization. According to the molecular docking results, the free binding energy between PC lipase and substrate was in the order of BDGAB < DEGSDEG < BSDEG < BSB. Thus, the enzymatic degradability of PBS-co-DEGS is more effective than that of PBS-co-BDGA.
在四氢呋喃（THF）/甲苯混合体系中，通过 Novozym 435（N435，固定化南极假丝酵母脂肪酶负载在丙烯树脂上）催化作用，研究了聚丁二酸丁二醇酯-共-二乙二醇琥珀酸酯（PBS-co-DEGS）和聚丁二酸丁二醇酯-共-丁二酸丁二醇酯（PBS-co-BDGA）之间的酶解降解行为差异，反应持续 30 h。这两种共聚物（通过醚键连接的醇改性）通过熔融缩聚合成，并通过 H NMR 进行了表征。通过凝胶渗透色谱（GPC）和热重分析（TGA）分别测定了降解前后的平均分子量和热性能。结果表明，从 0 h 到 12 h，二醇中的 DEG20（20%含量的二甘醇）的端基降解和二酸中的 DGA20（20%含量的丁二酸二醇）的分子内随机降解同时发生。TGA 曲线表明，用 N435 降解后，两种共聚物的 T-5%从约 300°C 降低到 210°C 以下。在降解产物（线性和环状低聚物中，没有出现低于 10 个聚合度的单体。根据分子对接结果，PC 脂肪酶与底物的自由结合能顺序为 BDGAB < DEGSDEG < BSDEG < BSB。因此，PBS-co-DEGS 的酶降解性比 PBS-co-BDGA 更有效。
