Techno-economic, life-cycle, and socioeconomic impact analysis of enzymatic recycling of poly(ethylene terephthalate)

TLDR

Esterases have emerged as important biocatalysts for enzyme‑based polyester recycling of poly(ethylene terephthalate) (PET) to terephthalic acid (TPA) and ethylene glycol (EG). The authors aim to assess the techno‑economic, life‑cycle, and socioeconomic viability of enzymatic PET recycling versus virgin TPA production. They construct a process model of enzymatic PET depolymerization and perform comparative analyses against conventional manufacturing. The analysis predicts that enzymatically recycled TPA can be cost‑competitive, reduce supply‑chain energy use by 69–83 % and GHG emissions by 17–43 % per kg, cut overall environmental impacts by up to 95 % in the US, generate up to 45 % more socioeconomic benefits, and identifies key research opportunities to advance PET recycling.

Abstract

Esterases have emerged as important biocatalysts for enzyme-based polyester recycling of poly(ethylene terephthalate) (PET) to terephthalic acid (TPA) and ethylene glycol (EG). Here, we present process modeling, techno-economic, life-cycle, and socioeconomic impact analyses for an enzymatic PET depolymerization-based recycling process, which we compare with virgin TPA manufacturing. We predict that enzymatically recycled TPA (rTPA) can be cost-competitive and highlight key areas to achieve this. In addition to favorable long-term socioeconomic benefits, rTPA can reduce total supply chain energy use by 69%–83% and greenhouse gas emissions by 17%–43% per kg of TPA. An economy-wide assessment for the US estimates that the TPA recycling process can reduce environmental impacts by up to 95% while generating up to 45% more socioeconomic benefits, also relative to virgin TPA production. Sensitivity analyses highlight impactful research opportunities to pursue toward realizing biological PET recycling and upcycling.