Poly(ethylene terephthalate) (PET) is synthesized via a rich ester bond between terephthalate (TPA) and ethylene glycol (EG). Because of this, PET degradation takes a long time and PET accumulates in the environment. Many studies have been conducted to improve PET degrading enzyme to increase the efficiency of PET depolymerization. However, enzymatic PET decomposition is still restricted, making upcycling and recycling difficult. Here, we report a novel PET degrading complex composed of Ideonella sakaiensis PETase and Candida antarctica lipase B (CALB) that improves degradability, binding ability and enzyme stability. The reaction mechanism of chimeric PETase (cPETase) and chimeric CALB (cCALB) was confirmed by PET and bis (2-hydroxyethyl terephthalate) (BHET). cPETase generated BHET and mono (2-hydroxyethyl terephthalate (MHET) and cCALB produced terephthalate (TPA). Carbohydrate binding module 3 (CBM3) in the scaffolding protein greatly improved PET film binding affinity. Finally, the final enzyme complex demonstrated a 6.5-fold and 8.0-fold increase in the efficiency of hydrolysis from PET with either high crystalline or waste to TPA than single enzymes, respectively. This complex could effectively break down waste PET while maintaining enzyme stability and would be applied for biological upcycling of TPA.

聚对苯二甲酸乙二醇酯 (PET) 是通过对苯二甲酸 (TPA) 和乙二醇 (EG) 之间的丰富酯键合成的。正因为如此，PET降解需要很长时间，并且PET会在环境中积累。已经进行了许多研究来改进PET降解酶以提高PET解聚的效率。然而，酶促PET分解仍然受到限制，使得升级和回收变得困难。在这里，我们报告了一种由Ideonella sakaiensis PETase 和Candida antarctica组成的新型 PET 降解复合物脂肪酶 B (CALB)，可提高降解性、结合能力和酶稳定性。PET和双(2-羟乙基对苯二甲酸酯)(BHET)证实了嵌合PETase (cPETase)和嵌合CALB (cCALB)的反应机理。cPETase 生成 BHET 和单 (2-对苯二甲酸羟乙酯 (MHET)，cCALB 生成对苯二甲酸酯 (TPA)。支架蛋白中的碳水化合物结合模块 3 (CBM3) 极大地提高了 PET 膜的结合亲和力。最后，最终的酶复合物显示出 6.5 倍与单一酶相比，高结晶或废PET水解为TPA的效率分别提高8.0倍，该复合物可有效分解废PET，同时保持酶稳定性，可用于TPA的生物升级。