Application of cutinase in the degradation of biodegradable polyester poly(butylene adipate-co-terephthalate)

Abstract

With the environmental pollution caused by waste plastics becoming increasingly serious, biodegradable polyester has become the focus of public attention. Poly(butylene adipate-co-terephthalate) (PBAT) is a biodegradable polyester formed by the copolymerization of aliphatic and aromatic groups, which has excellent performance of both. The degradation of PBAT under natural conditions requires strict environmental conditions and long degradation cycle. To address these shortcomings, this study explored the application of cutinase in PBAT degradation and the impact of butylene terephthalate (BT) content on the biodegradability of PBAT, so as to improve the degradation rate of PBAT. Five Polyester degrading enzymes from different sources were selected to degrade PBAT to pick out the most efficient enzyme. Subsequently, the degradation rate of PBAT materials with different BT content were determined and compared. The results showed that cutinase ICCG was the best enzyme for PBAT biodegradation, and the higher the BT content, the lower the degradation rate of PBAT. Furthermore, the optimum temperature, buffer type, pH, the ratio of enzyme to substrate (E/S) and substrate concentration in the degradation system were determined to be 75 ℃, Tris HCl, 9.0, 0.4% and 1.0% respectively. These findings may facilitate the application of cutinase in PBAT degradation.