This study presents a comprehensive process, economic, environmental, and socioeconomic analysis of the enzymatic recycling of poly(ethylene terephthalate), which is the most widely used synthetic polyester. The analyses predict that PET deconstruction using enzymes can achieve cost parity with terephthalic acid manufacturing as well as substantial reductions in both supply chain energy use and greenhouse gas emissions relative to virgin polyester manufacturing. This study also highlights key research areas for further impactful development of biocatalysis-enabled plastics recycling.

Reductive catalytic fractionation (RCF) is a promising approach to fractionate lignocellulose and convert lignin to a narrow product slate. To guide research towards commercialization, cost and sustainability must be considered....

Over 400 million metric tons of plastic waste are generated globally each year, resulting in pollution and lost resources. Recycling strategies can recapture this wasted material, but there is a lack of quantitative and transparent data on the capabilities and impacts of these processes. Here, we develop a data set of material quality, material retention, circularity, contamination tolerance, minimum selling price, greenhouse gas emissions, energy use, land use, toxicity, waste generation, and water use metrics for closed-loop polymer recycling technologies, including mechanical recycling and solvent-based dissolution of polyethylene, polyethylene terephthalate (PET), and polypropylene, as well as enzymatic hydrolysis, glycolysis, and vapor methanolysis of PET. Mechanical recycling and PET glycolysis display the best economic (9%−73% lower than competing technologies) and environmental (7%−88% lower) performances, while dissolution, enzymatic hydrolysis, and methanolysis provide the best recyclate material qualities (2%−27% higher). We identify electricity, steam, and organic solvents as top process contributors to these metrics and apply sensitivity and multicriteria decision analyses to highlight key future research areas. The estimates derived in this work provide a quantitative baseline for comparing and improving recycling technologies, can help reclaimers identify optimal end-of-life routes for given waste streams, and serve as a framework for assessing future innovations.

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As the demand for utilizing environment-friendly and sustainable energy sources is increasing, the adoption of waste-to-energy technologies has started gaining attention. Producing biogas via anaerobic digestion (AD) is promising and well-established; however, this process in many circumstances is unable to be cost competitive with natural gas. In this research, we provide a technical assessment of current process challenges and compare the cost of biogas production via the AD process from the literature, Aspen Plus process modeling, and CapdetWorks software. We also provide insights on critical factors affecting the AD process and recommendations on optimizing the process. We utilize four types of wet wastes, including wastewater sludge, food waste, swine manure, and fat, oil, and grease, to provide a quantitative assessment of theoretical energy yields of biogas production and its economic potential at different plant scales. Our results show that the cost of biogas production from process and economic models are in line with the literature with a potential to go even lower for small-scale plants with technological advancements. This research illuminates potential cost savings for biogas production using different wastes and guide investors to make informed decisions, while achieving waste management goals.