Performance of PBS-based copolymer containing different ether bond and its enzymatic degradation by molecular simulation

Poly(butylene succinate-co-thiodiglycol succinate) [P(BS-co-TDGS)] and poly(butylene succinate-co-diglycol succinate) [P(BS-co-DEGS)] were synthesized by incorporating thioether group and ether oxygen group to the main chain of poly(butylene succinate) (PBS). Their thermal properties and crystallinity were compared by thermography analysis(TG) and X-ray diffraction (XRD). The degradation and their differences were studied in aqueous media with Candida antarctica lipase N435 (CALB) as a catalyst. The possible state of aggregation of copolymers and the combination between N435 lipase and substrate were also studied by molecular simulation. The results verify that the crystallinity and thermal stability of P(BS-co-TDGS) decrease. In addition, molecular docking simulation results show that the binding energy of N435 enzyme and diethylene glyol succinic-diethylene glyol (DEGS-DEG) was larger. That is, the docking of substrate P(BS-co-DEGS) containing ester bond such as thiodiglycol succinate with the active site of N435 lipase was more stable.