Abstract：
The rising accumulation of poly(ethylene terephthalate) (PET) waste presents an urgent ecological challenge, necessitating an efficient and economical treatment technology. Here, we developed chemical-biological module clusters that perform chemical pretreatment, enzymatic degradation, and microbial assimilation for the large-scale treatment of PET waste. This module cluster included (i) a chemical pretreatment that involves incorporating polycaprolactone (PCL) at a weight ratio of 2% (PET:PCL = 98:2) into PET via mechanical blending, which effectively reduces the crystallinity and enhances degradation; (ii) enzymatic degradation using Thermobifida fusca cutinase variant (4Mz), that achieves complete degradation of pretreated PET at 300 g/L PET, with an enzymatic loading of 1 mg protein per gram of PET; and (iii) microbial assimilation, where Rhodococcus jostii RHA1 metabolizes the degradation products, assimilating each monomer at a rate above 90%. A comparative life cycle assessment demonstrated that the carbon emissions from our module clusters (0.25 kg CO2-eq/kg PET) are lower than those from other established approaches. This study pioneers a closed-loop system that seamlessly incorporates pretreatment, degradation, and assimilation processes, thus mitigating the environmental impacts of PET waste and propelling the development of a circular PET economy.
摘要：
聚对苯二甲酸乙二醇酯（PET）废物的不断积累提出了紧迫的生态挑战，需要有效和经济的处理技术。这里,我们开发了执行化学预处理的化学-生物模块集群，酶促降解，和微生物同化用于PET废物的大规模处理。该模块簇包括（i）化学预处理，涉及通过机械共混以2％的重量比（PET：PCL=98：2）将聚己内酯（PCL）掺入PET中，有效地降低结晶度并增强降解；（ii）使用Thermobifidafusca角质酶变体（4Mz）进行酶促降解，在300g/LPET下实现预处理的PET的完全降解，每克PET的酶负载为1毫克蛋白质；和（iii）微生物同化，华氏红球菌RHA1代谢降解产物，以90%以上的比率同化每个单体。比较生命周期评估表明，我们的模块集群（0.25kgCO2-eq/kgPET）的碳排放量低于其他既定方法的碳排放量。本研究开创了一个无缝结合预处理的闭环系统，降解，和同化过程，从而减轻PET废物对环境的影响并推动循环PET经济的发展。
