A better method of plastic recycling is in high demand. Plastic waste will be a growing problem unless processes are implemented to form a circular economy in plastic waste management, where sustainable reuse and recycling is prioritized, and the production of pollutant byproducts is minimized. We determined that compared to other methods of recycling PET wastes, biocatalytic methods can be the ideal process to avoid production of secondary pollutants, as shown in Figure 1. Since bioremediation breaks down plastics into its precursor components using this method might help push for an increase in recycling rates. As James Hallinan, business development manager of synthetic biology at Cambridge Consultants describes, “Creating precursors for making plastic, rather than recycling whole plastic into a lower-grade material, might incentivize more recycling because there’s a better market for the final product. ‘There might be more economic appetite, more industrial appetite, for those types of materials’” [1].

We anticipate the end users of our project to be researchers or industry employees looking to design and test new optimal sequences, or people working within the PET degradation world looking for new solutions. In developing this pipeline, we can provide a framework for other researchers to work with. This is where our custom Python package comes in. Our package has been optimized for use with not only PETase, but with other proteins and enzymes, being fully customizable and ready to test for other projects. We anticipate possible end users of the package to be future iGEM teams, computational biologists, and bioinformaticians.

Our current experiments are in a microscale setting as we tested on PET films rather than larger volumes of PET products. The feasibility of implementation of bioremediation for PET recycling is dependent on cost and time-effective production of large scale enzymatic production. In the future, we will need to test these enzymes’ catalytic efficiency with larger volumes of PET and design greater throughput production processes of candidate enzymes as well.

Other aspects we need to consider in proposed implementation include the challenges that waste management services face in sorting and transporting waste. If a biocatalyst is used in practice, it must be in accordance with the current workflow and regulatory standards in place. For example, even if we are able to optimize efficiency of PET degradation, there is still a need to optimize the processes of sorting and transporting waste and recyclables. We learned this especially from our Human Practices work with Facilities & Services, which helped us to realize that in depth communication with stakeholders involved is key to better understanding the needs of community and industry members. If we were to continue this project next year, we would like to expand upon this work to develop a hardware technology for optimized waste sorting. This hardware could be implemented into current practices to help address the F&S’s need of better sorting plastics, a solution which would have even more of an impact within our community. This technology can be paired with our current pipeline for better plastic waste management from start to end of the line.

References

1. Peters, Adele. “Could These Plastic-Eating Enzymes Be the Miracle Solution to Our Plastic Problem?” Fast Company, 3 Oct. 2019, https://www.fastcompany.com/90412215/could-this-plastic-eating-enzyme-be-the-miracle-solution-to-our-plastic-problem.

Figure 1: Methods used to recycle PET wastes