Microbial Enzyme Biotechnology to Reach Plastic Waste Circularity: Current Status, Problems and Perspectives

Area of Science:

• Biotechnology and Environmental Science
• Polymer Science and Engineering
• Waste Management and Circular Economy

Background:

• The global accumulation of synthetic plastic waste necessitates innovative recycling solutions.
• Microbial enzymes present emerging biotechnological tools for plastic depolymerization and waste circularity.
• Current enzyme-based recycling is limited, especially for non-polyester plastics and mixed waste streams.

Purpose of the Study:

• To review the prospective of biotechnological tools for plastic bio-recycling within European waste management frameworks.
• To assess the current capabilities and limitations of enzyme-based plastic recycling.
• To identify future directions for enhancing the contribution of biotechnology to plastic circularity.

Main Methods:

• Literature review of existing biotechnological approaches for plastic recycling.
• Analysis of the current plastic waste management landscape in Europe.
• Evaluation of enzyme efficacy on different plastic types, including polyethylene terephthalate (PET), polyurethanes, and polyolefins.

Main Results:

• Biotechnology tools can effectively support polyethylene terephthalate (PET) recycling, which constitutes a small fraction of unrecycled plastic waste.
• Polyurethanes and other recalcitrant thermoplastics remain challenging targets for current enzyme-based depolymerization.
• Enzyme-based processes are most effective on ideal polyester-based polymers.

Conclusions:

• Optimizing collection and sorting systems is crucial for integrating chemoenzymatic technologies with recalcitrant and mixed polymers.
• Development of new, environmentally friendly bio-based technologies is needed for broader plastic depolymerization.
• Future plastic materials should be designed for durability and susceptibility to enzymatic degradation to enhance circularity.