Our project involves creating strains of bacterial that can degrade and metabolize PET waste. As exciting as the project was, we recognized that our project would be met with an overwhelming concern if we ever wanted to realistically utilize our bacterial system to breakdown PET waste. For that reason, we decided to work towards engaging our local community in intellectual discussions about genetic engineering and biocontainment. Through public discourse and education, we hoped to increase awareness about not only the promise that synthetic biology holds for solving many global dilemmas but also to address many misconceptions people often have about genetic engineering.
Pathways to Science: West Campus Science Fair
Pathways to Science is an organization dedicated to inspiring the next generation of scientists by organizing events for middle and high schoolers to be explore the sciences. Each year, Pathways to Science organizes the Yale West Campus Science Fair where over 150 students come and participate in a fun day filled with workshops, demos, and tours of scientific research facilities. Since the Yale iGEM Team conducts their research in their lab on West Campus, we decided to reach out to the West Campus Science Fair organizers about hosting our own workshop and demo during the event. Luckily, the event organizers were delighted to have us and gave us our own time slot to host a workshop and demo.
During the workshop, we engaged the middle and high school students by first starting with a presentation about how synthetic biology can be used to address a variety of problems that plague society. After discussing very basic techniques used to genetically engineer organisms to have new functions, we did a quick demo using pool noodles to explain how cloning a gene into a plasmid works. We then opened up the floor for an open discussion and challenged the students to think critically about the impact that genetically engineered organisms would have on society and the world. We really encouraged them to also consider what type of ethical implications such biotechnology would have. Although it required some time for the discussion to gain momentum, the students began to talk about topics ranging from biocontainment to designer babies. As a souvenir, we gave them all glowstick “plasmid” bracelets to remind them about our lesson. Overall, we had a lot of fun teaching the students and hearing what they had to say about genetic engineering.
Yale Synapse: Resonance Conference
Yale Synapse is the outreach branch of the Yale Scientific that runs multiple community outreach events for the New Haven community. One of the largest events each year is the Resonance Conference, when about 100 students come to Yale to take student-led lessons about a variety of cutting-edge science topics. We decided to reach out to the conference organizers and asked if we could teach a lesson about the theory and application behind synthetic biology. After interviewing with them and demoing our lesson plan, they accepted our proposal and gave us an entire one hour time slot to teach our lesson. Our slidedeck we used for our lesson can be found here:
Link to Yale iGEM Resonance Lesson Slidedeck
During our lesson, we wanted to teach about genetic engineering and using biology to solve real-world problems. We used our iGEM project as a lens for the lesson so that students would have a tangible example to think about. We essentially posed the question about how we can engineer bacteria to break-down plastic. To start, we went over the basics about the central dogma of biology and then talked about how genetic information is translated into proteins with specialized functions. To hammer home the idea about the genetic code, we had them decode a “Secret Message” encoded in DNA that needed to be translated into an amino acid sequence. We then talked about taking advantage of this process to introduce new functions into organisms. In particular, we covered the details about how to construct and clone a gene into a plasmid, and then transforming/electroporating that plasmid into bacteria. By the end, students were asking us about the limits of genetic engineering about what else was possible, which was a great feeling for us. It showed that the students had really digested the information and were already thinking like researchers.
INTEGRATED Human Practices
Although we were extremely happy with our ability to reach out to the local community and educate the next generation of scientists about the benefits and limitations of genetic engineering, we wanted to go beyond and consult the experts about plastic waste to make sure our project was practical and relevant as a potential solution to resolving PET waste build-up.
Yale Office of Sustainability
To learn more about how plastic recycling works, we decided to reach out to the Yale Office of Sustainability. In particular, we were interested in how “single-stream recycling” worked on campus since all plastic recycling on campus is mixed in with other recyclables. From the Office of Sustainability, we were able to learn in-depth details about how “single-stream recycling” mixed recyclable waste is sorted out at recycling plants. We also learned about how certain plastic waste is unable to be recycled after the purity of the plastic has been compromised by previous rounds of recycling. These plastics are unable to be further recycles and would be a great target for our project. By creating a synthetic bacterial co-culture to degrade and metabolize PET waste, we would be able to take these low-quality, unrecyclable plastics and dispose of them safely in and environmentally friendly way. Their only concern was biocontainment because having a strain of plastic-eating bacteria escape from a controlled lab setting would compromise the utility of PET plastics.
Interview with Former Business Executive of GE/SABIC Plastics
To get a better understanding of how our research impacts the economy, the environment, and involves human practices, Yale iGEM Team member Lauren got in touch with Scott Telesz, a former business executive of GE/SABIC plastics, and scheduled a meeting. Over coffee, they discussed the complex issue of plastic degradation from a business and a science point of view.
Scott was thrilled to meet with Yale iGEM. Though a large part of his career was in developing plastics, he recognizes the harm plastic waste has on the environment and is a supporter of cleanup efforts. “The difficulty with plastic,” he says, “is that they are never going to go away in our society.” And he's referring to more than just their chemical staying power. Scott discussed the incredible benefits of plastics and the truly transformative effect they have had on society. They've made food production, transportation, health, and engineering reach levels they otherwise wouldn't have. The extremely durable plastic GE/SABIC creates for car construction, for example, makes vehicles much safer.
Scott stressed the fact that GE/SABIC produces many plastic polymers of different resins, temperatures, durability, and appearance; each polymer is generated with a couple specific purposes in mind. Scott and Lauren discussed the PET polymer and the controversy around it. Scott noted that the amount of waste generated by PET plastic was very much in part due to the increased globalization of commercial society and the transportation of goods across the world. The more packages and bottles Amazon and Coca-Cola ship the more the problem propagates, Scott said. And Amazon and Coca-Cola, with expanding markets, are not going to stop spreading their products around the world anytime soon.
So faced with the problem of all this waste, that is not biodegradable, what is the solution? Scott paused for a minute before launching into his take on the situation. For businesses, he began, the goal was at first clear and simple: make the best product at the lowest cost for your customers and for your company. Whatever material was the most durable and got the job done for the best price was chosen. However, that changed once the world started to note how detrimental plastic was to the environment.
“People started to care more about how their products effected the environment,” Scott discussed, “and that was great and revolutionized the way industry created and marketed their products. But recycling efforts and reusing aspects are not as easy as the public believes.” The reason plastics took off so fast is because of their incredible durability and when you reuse plastic and make products from "recycled material" the integrity of the structure is compromised, making customers unhappy. In addition, many people are not as educated or concerned about the environment. So, their plastic consumption habits or disposal methods remain unchanged.
Businesses like GE/SABIC have worked with creating plastic polymers from corn rather than oil to limit air pollution, but how to tackle the degradation problem is still a major issue. Scott observed that it is impractical to expect businesses to drastically change packaging or households to stop using water bottles. The solution has to come from the scientists, where the plastic polymer was first synthesized.
Scott was particularly drawn to the biological, genetic aspect of the Yale iGEM project; he was especially curious about the bio-containment dilemma and questioned how these modified genetic organisms were to attack the plastic. Lauren discussed her idea of huge bacteria "degradation" factories, where optimized E. coli strains were housed in vats, growing in the right media, and were "fed" with collected plastic to produce ethylene glycol and terephthalic acid. Scott remarked how both of those byproducts could be incredibly useful for industry and said the design was respectful of people's uneasiness to bacteria. However, Lauren and Scott were unsure how collection of plastics could be optimized to make this work, but Scott assured Lauren that if the byproducts could be resold back to companies to make more durable products with the same integrity than businesses would have a greater stake in sustainability practices.
How has our Human Practices and Integrated Human Practices work affected our project?
To address the widespread concerns about biocontainment that we encountered during our West Campus Science Fair, Resonance Lesson, interaction with the Yale Office of Sustainability, and interview with Scott Telesz, Former Business Executive of GE/SABIC Plastics, we had to dramatically alter our project design. First, for all of our experiments, we opted to use a strain of engineered E. coli that is unable to survive without biotin supplements. Preliminary studies have shown that this biotin-deficiency is hard to overcome via mutations. Also, there is rarely enough biotin present in the environment for the bacteria survive. Although it was quite a hassle to remember to add biotin supplements into all our media before culturing our cells, it was a step towards addressing public concerns about biocontainment.
To further address concerns about biocontainment, we decided to have the PET metabolism be spread out between two organisms in a co-culture. Having all the parts of the PET metabolic pathway in a single organism would more easily allow that organism to proliferate if it were able to escape the lab setting. By splitting the metabolic pathway across two organisms, both would have to simultaneously evolve mechanisms to survive off of PET plastic outside of the lab setting. Thus, it would be easier to contain a PET-degrading bacteria co-culture than a singular strain of PET-degrading bacteria.
Lastly, our discussions with Scott Telesz really changed the way we thought about our project’s end goal. Although we had initially only thought about using our system to completely get rid of PET plastic, we learned that it would be much more financially attractive to plastic-producing companies if we could use these enzymes to breakdown PET plastic into monomers, then use those monomers to repolymerize new plastic products. Thus, we could potentially have an additional application of our project. By creating a synthetic co-culture that can survive off of PET plastic, we can run directed evolution experiments to improve the functionality of PETase and MHETase. Then, using the improved evolved PETase and MHETase, we could mass-produce the enzymes and provide them to companies who recycle plastic. Not only would this help jumpstart funding for such an ambitious project, but it would also remove the need for high-energy chemical processes currently used for plastic recycling.
In the end, we were extremely happy with how our Human Practices and Integrated Human Practices have not only improved the communities in which we live, but also given us greater insight into how we should best think about our project’s future directions. Without having reached out and investigated these pressing issues, our project would have looked quite different than it does now.