聚对苯二甲酸乙二醇酯(PET)是废塑料的主要成分。酶促PET水解是最生态的回收技术。PET废物的生物再循环需要将PET完全解聚为对苯二甲酸酯和乙二醇。酶促PET解聚的历史揭示了PET工业解聚的两个关键问题:工业上可获得的PET水解酶和PET废物的预处理,以使其易于完全酶促水解。由于野生型酶都不能满足工业化的要求,已经进行了各种突变改进,通过经典技术到最先进的计算/机器学习技术。最近对PET水解酶的工程研究带来了新的见解,即底物结合槽的灵活性可以提高PET水解的效率,同时保持足够的热稳定性。尽管先前的研究仅集中在高于PET的玻璃化转变温度的酶热稳定性上。计划实施PET废物的工业生物回收,使用微粉化无定形PET。下一阶段必须是PET水解酶的开发,该水解酶可以有效地降解PET的结晶部分和目标PET材料的扩展。不仅是瓶子,还有纺织品,包,和微塑料。这篇综述讨论了PET水解酶的现状,它们的潜在应用,和他们的职业目标。PET水解酶必须是嗜热的,但是它们的操作必须低于70°C。•经典和最先进的工程方法对PET水解酶有用•晶体PET上的酶活性最有望用于未来的PET生物回收。
Polyethylene terephthalate (PET) is a major component of plastic waste. Enzymatic PET hydrolysis is the most ecofriendly recycling technology. The biorecycling of PET waste requires the complete depolymerization of PET to terephthalate and ethylene glycol. The history of enzymatic PET depolymerization has revealed two critical issues for the industrial depolymerization of PET: industrially available PET
hydrolases and pretreatment of PET waste to make it susceptible to full enzymatic hydrolysis. As none of the wild-type enzymes can satisfy the requirements for industrialization, various mutational improvements have been performed, through classical technology to state-of-the-art computational/machine-learning technology. Recent engineering studies on PET
hydrolases have brought a new insight that flexibility of the substrate-binding groove may improve the efficiency of PET hydrolysis while maintaining sufficient thermostability, although the previous studies focused only on enzymatic thermostability above the glass transition temperature of PET. Industrial biorecycling of PET waste is scheduled to be implemented, using micronized amorphous PET. Next stage must be the development of PET
hydrolases that can efficiently degrade crystalline parts of PET and expansion of target PET materials, not only bottles but also textiles, packages, and microplastics. This review discusses the current status of PET hydrolases, their potential applications, and their profespectal goals. KEY POINTS: • PET
hydrolases must be thermophilic, but their operation must be below 70 °C • Classical and state-of-the-art engineering approaches are useful for PET
hydrolases • Enzyme activity on crystalline PET is most expected for future PET biorecycling.