University College Cork Engineers Yeast to Advance Sustainable PET Recycling

The research, published in ACS Synthetic Biology, was led by Dr. Paul Young and his team from UCC's School of Biochemistry and Cell Biology, in collaboration with Prof. Justin Holmes from the School of Chemistry. The study forms part of a broader synthetic biology project focused on expanding the capabilities of yeast-based engineering platforms.

Polyethylene terephthalate (PET), commonly used in beverage bottles, food packaging, and textiles, is valued for its durability but remains difficult to degrade efficiently. To address this challenge, the UCC researchers engineered yeast cells to produce multiple enzymes capable of breaking PET down into reusable chemical building blocks.

The team initially employed an enzyme naturally found in compost environments, where it helps decompose waxy plant surfaces. By displaying this enzyme on the surface of yeast cells, the researchers enabled the cells to initiate PET degradation more effectively. They then introduced an additional protein that improves yeast attachment to plastic surfaces, significantly increasing PET breakdown efficiency.

In the final stage, the addition of a third enzyme enabled the complete conversion of intermediate degradation products into terephthalic acid (TPA), a core raw material used in the production of new PET resin. According to the researchers, this whole-cell biocatalyst approach could contribute to more energy-efficient and environmentally sustainable recycling processes in the future.

Beyond plastic recycling, the newly developed “MoClo YSD Toolkit 2.0” also supports applications in protein interaction analysis, recombinant protein production, and broader biotechnology research. The modular platform includes enhanced protein anchoring systems, detection tags, and secretion-enhancing yeast factors designed to improve synthetic biology workflows.

Dr. Paul Young emphasized that the current experiments were conducted at laboratory scale and that economically viable large-scale enzymatic recycling of PET and other plastics remains a long-term challenge. He also noted that advances in recycling technology should not be viewed as justification for maintaining high levels of fossil-fuel-based plastic production.

Source: University College Cork (UCC)