Selective and Sequential Catalysed Depolymerisation of Polyester Plastics

向循环塑料经济过渡对于保护资源、保留材料价值和防止猖獗的污染至关重要。酶促塑料降解或生物回收为当前的机械和化学回收方法提供了一种新的替代方案，并且是难以回收的塑料废物（如聚合物-聚合物共混物）的一种有前途的选择。定向进化是开发新型塑料降解酶的一种强有力的工程策略;以前的工作探索了活性和热稳定性PETase的定向进化。我的新工作旨在扩大目前酶促塑料降解的底物范围，以包括聚（双酚A）碳酸酯（BPA-PC），这是一种以每年百万吨规模生产的工程热塑性塑料。BPA-PC通常与其他水解不稳定的聚合物如PET和PBT共混，使得高度选择性的BPA-PC解聚酶成为有吸引力的靶标。为此，已经鉴定了BPA-PC降解酶，并且正在进行第一轮定向进化。

Transitioning to a circular plastics economy is essential for the conservation of resources, retention of material value, and prevention of rampant pollution. Enzymatic plastic degradation, or biological recycling, offers a novel alternative to current mechanical and chemical recycling methods and is a promising option for difficult-to-recycle plastic waste, such a polymer-polymer blends. Directed evolution is a powerful engineering strategy in developing novel plastic degrading enzymes; previous work explored the directed evolution of an active and thermostable PETase. My new work seeks to broaden the current substrate scope of enzymatic plastic degradation to include poly(bisphenol-A) carbonate (BPA-PC), an engineering thermoplastic produced on a million ton per annum scale. BPA-PC is commonly blended with other hydrolytically labile polymers such as PET and PBT, making a highly selective BPA-PC depolymerase an attractive target. To this end, a BPA-PC degrading enzyme has been identified, and a first round of directed evolution is underway.