School of Chemistry, Federal University of Rio de Janeiro (UFRJ) - Cidade Universitária, Rio de Janeiro, RJ CEP 21949-900, Brazil.
Petrobras Research, Development and Innovation Center (Cenpes), Av. Horácio Macedo, n° 950 - Cidade Universitária, Rio de Janeiro, RJ CEP 21941-915, Brazil.
Biotechnol Adv. 2021 Nov 15;52:107811. doi: 10.1016/j.biotechadv.2021.107811. Epub 2021 Jul 29.
Plastics production and recycling chains must be refitted to a circular economy. Poly(ethylene terephthalate) (PET) is especially suitable for recycling because of its hydrolysable ester bonds and high environmental impact due to employment in single-use packaging, so that recycling processes utilizing enzymes are a promising biotechnological route to monomer recovery. However, enzymatic PET depolymerization still faces challenges to become a competitive route at an industrial level. In this review, PET characteristics as a substrate for enzymes are discussed, as well as the analytical methods used to evaluate the reaction progress. A comprehensive view on the biocatalysts used is discussed. Subsequently, different strategies pursued to improve enzymatic PET depolymerization are presented, including enzyme modification through mutagenesis, utilization of multiple enzymes, improvement of the interaction between enzymes and the hydrophobic surface of PET, and various reaction conditions (e.g., particle size, reaction medium, agitation, and additives). All scientific developments regarding these different aspects of PET depolymerization are crucial to offer a scalable and competitive technology. However, they must be integrated into global processes from upstream to downstream, discussed here at the final sections, which must be evaluated for their economic feasibility and life cycle assessment to check if PET recycling chains can be broadly incorporated into the future circular economy.
塑料生产和回收链必须适应循环经济。聚对苯二甲酸乙二醇酯（PET）特别适合回收，因为其酯键可水解，而且由于其在一次性包装中的应用，对环境的影响很大，因此利用酶的回收工艺是一种很有前途的生物技术途径，可从单体中回收。然而，酶法 PET 解聚要成为工业级的竞争途径仍面临挑战。在这篇综述中，讨论了 PET 作为酶底物的特性，以及用于评估反应进展的分析方法。还全面讨论了所使用的生物催化剂。随后，提出了提高酶法 PET 解聚的不同策略，包括通过突变酶进行酶修饰、利用多种酶、提高酶与 PET 疏水面之间的相互作用，以及各种反应条件（例如，颗粒大小、反应介质、搅拌和添加剂）。所有这些不同方面的 PET 解聚的科学发展对于提供可扩展和具有竞争力的技术都至关重要。然而，它们必须整合到从上游到下游的全球工艺中，在最后几节中进行讨论，必须对其经济可行性和生命周期评估进行评估，以检查 PET 回收链是否可以广泛纳入未来的循环经济。
