iAMB - Institute of Applied Microbiology. ABBt - Aachen Biology and Biotechnology, RWTH Aachen University, Worringerweg 1, D-52074, Aachen, Germany.
BiOrbic - SFI Bioeconomy Research Centre, University College Dublin, Belfield, Dublin 4, Ireland; School of Biomolecular and Biomedical Science and UCD Earth Institute, University College Dublin, Belfield, Dublin 4, Ireland.
Metab Eng. 2021 Jul;66:167-178. doi: 10.1016/j.ymben.2021.03.011. Epub 2021 Apr 16.
Over 359 million tons of plastics were produced worldwide in 2018, with significant growth expected in the near future, resulting in the global challenge of end-of-life management. The recent identification of enzymes that degrade plastics previously considered non-biodegradable opens up opportunities to steer the plastic recycling industry into the realm of biotechnology. Here, the sequential conversion of post-consumer polyethylene terephthalate (PET) into two types of bioplastics is presented: a medium chain-length polyhydroxyalkanoate (PHA) and a novel bio-based poly(amide urethane) (bio-PU). PET films are hydrolyzed by a thermostable polyester hydrolase yielding highly pure terephthalate and ethylene glycol. The obtained hydrolysate is used directly as a feedstock for a terephthalate-degrading Pseudomonas umsongensis GO16, also evolved to efficiently metabolize ethylene glycol, to produce PHA. The strain is further modified to secrete hydroxyalkanoyloxy-alkanoates (HAAs), which are used as monomers for the chemo-catalytic synthesis of bio-PU. In short, a novel value-chain for PET upcycling is shown that circumvents the costly purification of PET monomers, adding technological flexibility to the global challenge of end-of-life management of plastics.
2018 年，全球生产了超过 3.59 亿吨塑料，预计在不久的将来还会有显著增长，这导致了全球范围内塑料处理的挑战。最近发现了能够降解以前被认为不可生物降解的塑料的酶，这为将塑料回收行业推向生物技术领域提供了机会。在这里，我们展示了将消费后的聚对苯二甲酸乙二醇酯（PET）连续转化为两种类型的生物塑料：一种中链长度的聚羟基烷酸酯（PHA）和一种新型的生物基聚（酰胺 氨酯）（bio-PU）。通过热稳定的聚酯水解酶将 PET 薄膜水解，得到高纯度的对苯二甲酸和乙二醇。所得的水解产物可直接用作对苯二甲酸降解菌恶臭假单胞菌 GO16 的原料，该菌也经过进化以有效地代谢乙二醇，从而生产 PHA。该菌株进一步被修饰以分泌羟基烷氧基-烷酸酯（HAAs），这些 HAAs 可用作化学催化合成 bio-PU 的单体。简而言之，我们展示了一种新的 PET 升级回收价值链，该价值链避免了昂贵的 PET 单体的纯化，为解决塑料生命周期管理的全球性挑战增加了技术灵活性。
