Chemical recycling and upcycling of plastics will be critical technologies to address the plastic pollution challenge. Given multiple process options for recycling plastics, rigorous process analysis is necessary to identify challenges that must be overcome for a technology to reach an industrial scale. For poly(ethylene terephthalate) (PET) recycling, several chemical recycling strategies have been proposed and, in some cases—chemo-catalytic and thermal approaches—are being scaled up. Given that PET exhibits labile ester bonds that are also common in natural biological systems, the research community is vigorously pursuing the engineering of esterase enzymes to depolymerize PET to terephthalic acid (TPA) and ethylene glycol (EG).<br/><br/>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.

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

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