Polyethylene (PET) plastic was once described as a miracle material during its early production and usage in the 1950s. With its expanding commercialization and application throughout society over the last 60 years, plastic pollution has grown to an unimaginable scale. Despite efforts to reduce plastic waste with recycling programs, plastic pollution continues to be a growing problem. Hence, our team has decided to investigate a biological solution to tackle the situation, specifically focusing on the application of PETase, the plastic degrading enzyme.
We began our work conducting preliminary research to identify the scope of the plastic waste issue and how it impacts society on a social, economic, political, and environmental level. We reviewed the literature that highlighted the current recycling processes in Canada, as well as the environmental and industrial impact of PET and its microplastics. We also studied the PET degradation pathway to gain a better understanding of the actual chemistry of the enzyme itself, and identify the potential positive (i.e. less costly compared to current chemical processes) and negative impacts (i.e. safety concerns for humans and wildlife) of introducing PETase to different environments (see our Literature Review here).
With this background knowledge in hand, we were able to consider our project from both social and scientific perspectives, and identify areas of research to pursue in our human policy and practices work. We decided to engage with two different social spheres - at a local, municipal level and within the industry.
Team:Toronto/Human Practices
Human Practices
Integrated Human Practices
Home Sweet Home
We thought it would be important to start by learning more about the recycling process in our own backyard and explore how our project might fit into that context. To do so, we approached Reno Strano, the waste management supervisor at the University of Toronto, St. George. Reno oversees and develops programs for waste collection on campus. With our initial plan of applying our modified PETase in a consumer context, namely packaging cultures in plastic water bottle labels that could be activated by the consumer after use, we became concerned with the reception it would receive, especially considering the stigma that is generally associated with bacteria and genetically modified organisms. Reno, however, mentioned he personally he had no issue interacting with PETase in waste (i.e. water bottle label) because he comes into contact with bacteria daily. From our conversation, we also learned that the most significant and universal barrier to effective waste management is the lack of participation — that is to say, the disposal of things in the wrong place due to a lack of awareness. This results in the contamination of plastics which presents barriers to effective recycling. The best way to combat this lack of awareness is through direct outreach. Ease, efficiency, cost-effectiveness, and especially consumer accessibility all had to be taken into consideration in implementing new technology for waste management. According to him, the effectiveness of our technology was a matter of people knowing how to use it, what to do with it after, and actually following through. These raised important considerations in the practicality of our implementation. Before parting with Reno, he provided contacts to individuals that dealt with waste management within the city of Toronto, believing it was important for us to understand the recycling process at a municipal level.Considering Reno’s advice, we decided we needed a broader take on the potential impacts of our project. With his contact information, we were able to speak with Sean Hurley, a project lead at the City of Toronto Solid Waste Management Services, and Sumantra Datta-Ray, a lead engineer within the Unit for Research, Innovation, and a Circular Economy. In reaching out to them, we hoped to learn about waste management programs within the city and the overall recycling process, as well as gain feedback on possible implementations of our project. From our conversation with them, we learned about the current waste collection and sorting strategies. Cross-contamination becomes a huge issue in properly recycling waste because it does not allow the sorting mechanism to function properly. For example, air jets that are intended to shoot plastic water bottles off of the sorting belt are compromised if the water bottle still contains liquids. We also learned that due to a constant influx of people, the city looks for waste management strategies that are easy as possible for people to participate in. Based on past negative experiences with employing enzymatic methods, they recommended that we consider environmental impacts on our enzyme, as well as that of cross-contamination. Finally, we learned that the success of a recycling program was determined by overall plastic diversion from the landfill, making the recovery of raw materials left at the end of the PETase metabolic pathway of particular interest. With this new insight into the need for raw material recovery, we realized we may have to approach our project in a more industrial route and had to approach other experts in the field.
To the Industry we go!
To gain better insight into the plastic industry itself, we spoke to Dan Lantz, director of PACNext!, a consortium of corporations involved in the plastic packaging value chain, pursuing a common goal of eliminating plastic packaging waste. From our conversation, we learned that there is significant corporate interest and investment in technologies and strategies aiming towards achieving a circular economy, including enzymatic/chemical recycling. This can be attributed to a widespread corporate concern with “the better thing to do”, and a larger movement of public (and by extension, shareholder) interest towards sustainable practices. More than 96 corporations are looking into chemical recycling alone, so the novelty of our technology was really in the enzyme itself, rather than our approach. Regarding chemical recycling specifically, Dan Lantz gave an estimated 5-10 years before its widespread implementation but apprehended a competition with mechanical recycling because the system itself is effective enough as it is. Like Sumantra Datta-Ray and Sean Hurley, he further emphasized the interest in recovering raw monomers/polymers from PET degradation, as it is both a valuable resource for plastic companies and a standard by which program success rates are determined. The potential for raw material recovery is also one of the largest appeals of chemical recycling: whereas chemical recycling has the potential to be infinite, mechanically recycled plastic can only be sent around the cycle seven times before losing properties.We also spoke to Peel Plastics, a local plastic packaging company in the GTA area, also a member of the Sustainable Packaging Coalition, with a strong interest in greener approaches to produce plastic packaging products. They identified that plastic packaging is better than other packaging materials in terms of overall cost, manufacturing process, product weight (usability), etc. Current methods of dealing with post-industrial waste, such as converting material into plastic lumber, have proven to not be a long-term viable solution, which reaffirmed the need for new technology to deal with post-industrial waste. As a plastics packaging company, in the future, they would like to see the plastics being able to be continuously recycled, especially a successful chemical recycling process that is much less demanding on the environment. They raised the concern of whether PETase could still effectively degrade plastics even in the presence of contamination, such as food leftovers. They also emphasized the need to consider the actual feasibility of our project, as though there are already plenty of alternative methods for PET degradation, none of them are economically feasible on a mass scale.
Human Practices
OpMed
Mooredale Summer Camp
Part 1
- Presentation: Introduction to plastics and recycling. A 10-minute introduction to plastics: their ever-presence in everyday life, the benefits of recycling and how it works.
- Pass the trash relay race: kids are divided into teams and compete to sort items into the correct recycling or garbage bins. This tests the children’s ability to recall proper recycling methods and ensures that we successfully introduced the concepts to them.
Part 2
- We developed an easy and fun way to explain the concept of PETase through an activity called PETase tag (5-10 min). We integrated our project to share with the kids, where we introduce them to the concept of PETase and its use in synthetic biology to solve a world problem. We introduced our project as plastic-eating enzymes. The game: When a person who is “plastic” is tagged by a person who is “PETase” they have to link arms with them and try to tag other people to add onto the chain (using PET as energy).
- “Monster Maker” Art Activity (20 min): kids make plastic-eating monsters out of recycled material. This final creative activity provides them an opportunity to reuse items in interesting ways.
Art Gala - “Thank you for Shopping”
- How has plastic impacted the experiences of people and animals worldwide?
- As climates and ecosystems change, what do we imagine is in store for our future?
- How should we evaluate our plastic use and how should we treat the Earth moving forward?
The title of the art gala, “Thank You for Shopping,” was inspired by the widely adopted slogan that is printed across single-use plastic grocery bags. This title addressed its audience directly, forcing the complacent consumer to accept accountability. We had a booth selling baked goods and science-themed stickers, and spoke to passing students about iGEM and the plastic waste issue.
Syntalks Podcast
Finally, to engage with the local synthetic biology community, this year we decided to continue our podcast, SynTalks. Throughout our episodes, we covered a wide array of topics in synthetic biology and interviewed individuals in the field. The first episode introduced the public to our 2019 project and provided insight into the design process as well as handling group dynamics amongst the three sub-teams. This episode highlighted the diverse backgrounds and goals of the iGEM members. Subsequently, we recorded “research spotlight” episodes where we interviewed researchers at the University of Toronto about their cutting-edge research in genetic engineering and synthetic biology. Podcast episodes were posted to SoundCloud and Youtube. Through our episodes, we hoped to spread information about our project, synthetic biology as a field, and current synthetic biology projects of interest.Conclusion
Our conversations with Reno Strano, Sean Hurley, Sumantra Datta-Ray, and Dan Lantz were influential on the direction of our project. Initially, we were considering a consumer-oriented application of our project, i.e. housing the modified PETase in plastic water bottle labels that could be activated by the consumer before discarding. However, in considering the difficulties caused by a lack of consumer engagement in recycling raised by Reno, the complexity of testing the efficacy of our product raised by Sumantra Datta-Ray and Sean Hurley, and the reiterated interest in chemical recycling and the potential to reclaim raw materials, we decided to explore a more industrial application of our project. Thus, we decided to explore the possibility of extracting EG/TPA in order to fulfill the criteria for diversion. Accordingly, we decided to design a bioreactor that would be able to facilitate PET degradation and TPA/EG extraction. Although the subject of contamination was not explored in the wet or dry lab, we still decided to tackle the project with outreach events. Additionally, we approached the community across different age groups, from young children to young adults, to reiterate the importance of communication and teaching of proper recycling techniques to mitigate further plastic pollution in the environment.