Team:KEYSTONE/Human Practices
HUMAN PRACTICE
Our project aims to create and implement PET plastic bins in rural areas where access is diffucult, so recycling them is neither feasible or economically desirable. By making the plastic bin intriguing – through emitting fragrance produced by linalool and demonstrating of PET degradation – we encourage more people to classify garbages, stop littering, and be more aware of worldwide plastic waste issues. By degrading PET into terephthalic acid (TPA) and ethylene glycol (EG), we produce more profit, thus more incentive for the local communities to recycle, as TPA and EG are more valuable than PET alone. Moreover, if we could successfully transform TPA and EG into carbon sources, the plastic bottles thrown into the bins would be completely gone, making no footprints to our environment.
Our project solves real-life issues related to our environment and our society, closely connected to our daily lives and our future lives. Our project influence people, and their attitudes also determine if our project is successful or not. As a result, we did not approach the problem simply from a technical perspectives, but also sought views of experts and the public, to incorporate our project into the real world.
The DAVI Framework
We created the DAVI framework to guide our human practice. DAVI stands for discover, aim, verify, and improve, four important stages to develop our project: we discover specific issues that we can tackle in the field of plastic pollution, we aim our project based on this need, we verify if our project is accepted by public, and we improve the technology to make our product more efficient. In all four stages, we talked to experts and the general crowd, who give us invaluable opinions and suggestions.
In the context of our project, we discovered, through talking to the secretary of the Plastic Reuse and Recycle Association, that PET recycling has evolved into a comprehensive and complete cycle within urban areas, with no need for degradation, though plastic pollution remains unsolved in places where the urban PET recycling cycle cannot reach. By talking to various environmental NGOs working to eliminate PET littering, we aimed our project to the remote tourist sites, where collecting and recycling the plastic is not possible or economically desirable, therefore creating pollutions. We located four places where our project could be used: the Bali Islands, the Great Wall, the Nanshan mountain, and the Tietan plateau. After disseminating surveys and receiving over 280 responses, we confirmed that our project is necessary and accepted in the public’s opinion. Eventually, implementing suggestions we received from prof. Liu, we improved the degradation efficiency of our LCC enzyme.
DISCOVER: Interview with the Plastic Reuse and Recycle Association
- Interviewee: Xue Yang, secretary of the Plastic Reuse and Recycle Association, China
- Purpose: to find out the procedures within the currently existing plastic waste management system, their potential problems & needs
Our initial idea for the project was to place these apparatus in communities and neighborhoods in cities like Beijing. Therefore, we contacted Mr. Xue Yang and appointed an online interview.
Important takeaways
Q: How are PET plastic wastes managed and recycled in China? What portion of PET plastic are recycled and how much are wasted?
The ragpickers operate a mature PET recycling industry.
A: Contrary to common belief, PET plastic, in fact, barely creates any waste or damage to the environment in most regions because with a decent recycling system, PET is used to be recycled into many different products, round after round. Although China’s trash classification system is deficient, the abundant ragpickers in China pick out almost all reusable trash, especially those with great value such as PET, which can be sold to factories at a rather high price. These collected plastics would arrive at factories, and after simple cleaning, the plastics would be grinded into tiny granules. Bottles could be incorporated into sneakers, towels, and the fabrics of sports clothing. Bottle caps could be processed into safety nets for construction sites. Even the bottle tags could become sewage pipes. “The medias today are demonizing plastic. In fact, owing to the ragpickers, most PET plastics are not wasted in China.”
Wasted plastic bottles are being packed and transported to factories to recycle. Photo by Nick Fewing.
Q: If so, do you think a project such as ours (degrading PET plastic with enzymes), with the goal of getting rid of plastic waste from the source (*our original idea was to place these apparatus in communities and neighborhoods)?
A: No. The PET production and recycling industry is a well-established economy, there is no need and it will only disrupt the existing economic system. Collecting and selling PET provides great revenue for the ragpickers, and plastic industries have mature and efficient systems of recycling used PET and profiting from it.
Outcome of interview: shift of target product application
After our interview with Mr. Xue, we reflected on our initial idea of putting plastic-degrading bins in communities and neighborhoods in the city, which is now proven ineffective to solving pollution problems. After intense brainstorming and conversations, we decided to shift our project focus to plastic collection in remote or underdeveloped areas, where systems that largely depend on waste sorting, ragpickers and well-established recycling industries could not cover.
On that note, we planned to interview personnels with thorough knowledge on the waste-management and plastic pollution situations in those potential regions, which leads to our next set of interviews.
AIM: Interview with Yahui Huang, Sally Silverstone, and William Lindesay
- Interviewee:Sally Silverstone and Rósa Björk Halldórsdóttir. Ms. Sally Silverstone is the chief financial officer and director of education in the Biosphere Foundation, a non-profit organization working to save the Bali islands from devastating ecological changes, through empowering individuals through education, and engaging with local communities to create solutions. Ms. Rósa Björk Halldórsdóttir is the trash ambassador of the foundation, working with locals to classify and eliminate trash, as well as with resorts to find methods to manage trash.
- Interviewee:Yanhui Huang and Dan Luo, two Chinese conservationists, who founded the Clean Heart Clean Mountain movement that organizes volunteers into remote areas in China to collect trashes by hand.
- Interviewee:William Lindesay, a British who has worked on eliminating trash pollution on the Great Wall for over 30 years.
- Purpose:to find out places such as the Bali islands, the Great Wall, and the high Nanshan mountains may need a PET-degrading bin.
Interview with Sally Silverstone and Rósa Björk Halldórsdóttir
Important Takeaways:
Q: How severe is the plastic waste problem in the area you are working on? How are they influencing the environment?
20% of all trashes end up outside of any bins
Dan Luo: Trash pollution problems we witnessed while collecting them are more severe than we thought of. When I was climbing Mount Bogda in Xinjiang, I was shocked to see plastic wrappings and bottles everywhere, disposed by hikers. People go and collect trashes annually along the Qinghai-Tibet Highway, located on the Tibet Plateau, but they could never finish the job, as these “runaway trash” are continuously disposed at a faster rate than their collection. In places like the Muztagh Mountain (altitude 7909 meters), our volunteers once cleared up 700 kilograms of trash.
William Lindesay: Last year, me and a group of volunteers collected 331 bags of trash on the Great wall. The Great Wall is at least 1000 km long, stretching from Beijing to Hebei province, and our trash collection only covered a small portion of the Wall. Just imagine how much trash there must be.
Sally Silverstone & Rósa Björk Halldórsdóttir: Plastic problems are very severe on the Bali Islands due to the collective efforts of resorts, tourists, and locals. The Bali islands possess sensitive and fragile ecosystems, which could be easily destroyed by plastics wastes. On some protected islands, plastics created by tourists sink into the ocean, and affect the corals – many corals are even growing on top of layers of plastic.
Q: How did plastic waste become a crisis in the area you are working on?
What is not burned at home is ending up in the oceans.
Sally Silverstone & Rósa Björk Halldórsdóttir: The key reason why plastic is a huge problem at Bali islands is that most plastics could be recycled but was not, as there is an extreme shortage of infrastructures for waste managements in Bali. Some villages don’t even have the basic facility of a trash can, and people either burn these valuable and reusable materials, or dump them into rivers, which eventually end up in the ocean. As for tourists, with only temporal facilities and lack of trash bins, most trashes are left on the beach, which also tumble into the ocean. Due to difficulties in managing trashes – the closest industrial recycling plastic processors is based in Java, 492 miles away – resorts chose to ignore their trash responsibilities, and either store trash in dumping places or burn them.
Cows eating plastic at a plastic dumping place in Bali. Photo provided by Rósa Björk Halldórsdóttir.
Yanhui Huang & Dan Luo: Lack of infrastructure and motivation caused such problems in the remote mountains in China. On the Tibet pastorals, litters made by the nomads are continuing to grow. As they come into contact with urban lifestyles, they started to produce more trash through buying things with plastic. However, this change of lifestyle is faster than the change in system, and no adequate plastic recycling system are established on the vast grasslands, causing trash to accumulate. In areas that could be accessed, people do not collect plastics because they receive too little profit, reduced by the transportation fee. For example, in remote villages of the Tibet Plateau and in the Nanshan mountains, access with cars is possible, but because they are so far away from any plastic recycling industries, the cost of collecting them exceeds the profit.
You see the city clean. But if you walk along its borders, it’s mountains and mountains of unmanaged trashes.
William Lindesay: The wild Great Walls have absolutely no established systems responsible for trash littering created by hikers. In parts of the Great Wall requiring a ticket, proper garbage bins are established, and the government hire people to do the cleaning regularly. Although it is not ideal and littering is still a problem, it is better than the wild walls. On the wild wall, even bins are nonexistent, and trash are everywhere. Some initiated programs to pay local people to become rangers, who will pick up trashes along the Wall regularly, and send them into nearby towns. However, this program closed down because it cannot be self-sustained, as the cost is greater than the profit earned by selling the trash. The rangers also did not fulfill their job responsibility, because they don’t get paid well (less than 300 dollars per month), and the trash cans are often very smelly and nasty, with trash scattering all around it, so the rangers are reluctant to touch them.
Q: How did you tackle these plastic waste problems? Sally Silverstone & Rósa Björk Halldórsdóttir: We collected recyclables to sell, educated the locals about reducing single-use plastic, and hired people to sort trashes. However, selling the plastics could not help, as the carbon footprint sin transporting the recyclables creates more burden to the environment; the people whom their hired also run away, leaving plastic pollution unsolved. As a result, iGEM_KEYSTONE’s trash can would help in solving Bali’s trash problems, with our project assisting the current system developed by Biosphere Foundation.
People need to manually collect trashes on the Bali Island. Photo provided by Rósa Björk Halldórsdóttir.
Q: What suggestions will you give us about our project? Sally Silverstone & Rósa Björk Halldórsdóttir:
- The trash cans shall be animal-proven, in case deer and monkeys seek food from the bins
- To prevent people putting in other things like tin cans and other types of plastic into the bins, the implementation of the bins should be accompanied by good education programs.
Yanhui Huang & Dan Luo:
- The trash bin should also contain degradation for other types of plastics, like PE, PP, and HDP. These types of plastic are also quite common when we are collecting the runaway trashes.
- Put the bins in tourist areas with no entry tickets and road intersections. These are places where people like to litter yet no one is paid to manage them.
William Lindesay:
- Use pedals on the trash can instead of hand-hold ones, because many hand-hold trash cans are often contaminated by gums.
- Try out our trash cans on the part of Great Wall called Jinshanling. The office who manages that part of the Great Wall has high environmental awareness, so we should consider trying out the project in that place to see people’s reactions.
- The trash can would be very useful on the wild wall where trashes are not managed at all. However, as a UNESCO-protected site, it is prohibited to put anything onto the Great Wall without authorization.
- The cans should be accompanied by heavy science educations and effective advertisements. For example, one of the very effective campaigns Mr. Lindesay saw was only a written board with a question “Why have you trashed this area?” and three choices: “I hate society”, “I am an idiot”, and “I cannot control myself”.
Outcome of the three interviews: Solidified the aim of creating remote trash cans
All the three interviews supported our aim to build trash cans in remote areas where plastic recycle industries cannot access, in order to eliminate plastic pollution. The three interviews provided invaluable insights into the types of locations to establish our trash cans – in popular hiker destinations and on tourist-crowded islands.
The current plastic pollution problem at the Bali Islands, caused by their lack of plastic-recycling infrastructures, can be effectively reduced by our trash bin. The huge amounts of plastic on the isolated Bali islands, created by both tourists and locals, are either burned or disposed in nature, both of which harms the environment. However, if our bins are introduced, then the plastics could possibly become carbon sources to be completely gone. Plastic pollutions are also severe, according to Ms. Huang, in remote mountains such as Nanshan mountain in Xinjiang province of China, where people hike and leave their used drink bottles behind. Because these places require no tickets, no trash bins or any facilities alike are erected there. Our trash bin, as a result, could prevents these hikers to litter their plastic bottles in the wild due to lack of bins. Our bins can also be erected on the wild Great Wall, where littering is everywhere as no one is responsible for managing them, according to Mr. Lindesay.
Runaway plastic bottles that Clean Mountain Clean Heart team collected on the Nanshan Mountain in Xinjiang. Photo provided by Ms. Yanhui Huang.
Based on this information, we developed our project to suit conditions at islands and remote mountains. For instance, we used solar panels for the hardware, considering that there are a lot of sunlight on the islands and on mountaintops. We also designed the bin opening to be animal-proof, to avoid the abundant wildlife on the Bali islands harming themselves with the trash bin.
The interviews also bring to sight several concerns that our project might face in the future. All three interviewees told us, that based on their experiences on people’s engagements in classifying their trashes, it is likely that people would throw random things inside our trash bin that is designed for only PET bottles. As a result, they stressed the importance of education to show people what type of things they should throw into the trash cans. Corresponding to their suggestions, we designed a pamphlet to teach trash classification and created a poster board where people write their comments to tell tourists what type of trashes they should throw in (see Public Engagement). The three interviewees also mentioned that the plastic wastes they collected consist of not only PET bottles, but also plastic bags, which are made of polyethylene, or PE. To degrade both plastic bottles and plastic bags, we collaborated with iGEM_BUCT team, who are developing PE-degrading E. coli, and incorporated their E. coli product into a section of our hardware (see Partnership.)
VERIFY: Public surveys
After settling down on a narrow and clear topic, we decided to disseminate surveys which asks the public’s opinion regarding our project and plastic pollution. We collected a total of 281 survey results, distributed online due to stricter regulations in times of a pandemic.
A full analysis of our survey can be seen here.
From a scale of 1 to 5, what is your acceptance rate for synthetic biology/genetic engineering/genetic modification?
The average rating of acceptance towards synthetic biology, genetic engineering and genetic modification is 3.39 out of 5. This means that a majority of people accptes synthetic biology to be incorporated into products that they use daily, such as food and public facilities. Although the acceptance rate could still be improved through means of public education, this result still shows how our trash bin will likely be accepted by the majority of people.
How much do you care about environmental protection?
This result reflect the public's concern for the environment: 4.2 concern rate out of 5. This is a very high percentage, showing that people are very aware of the environment and often support environmental-protection activities. Therefore, our project, aimed to eliminate plastic littering problem, would likely be supported by these environmentally-conscious people.
When you travel, will you pay attention to the environmental conditions of the tourist sites, especially the damages tourists created?
This pie chart reflects that most people are aware of the environmental conditions while traveling. More than 94% of the respondents pays attention to these conditions, and 54% of them pays their full attention. Only 1% do not care about the environmental conditions of the scenic spot. It could be concluded that the health of the environment is relatively important to tourists. If the environment of the scenic spot can be further optimized, more tourists may be willing to pay attention to the scenic spot. Therefore, this verifies that our product meets the needs of the public, because our trash can can not only help to degrade garbage in remote scenic spots and make them cleaner, but also produce fragrance. By changing the odorous trash cans into fragrant ones, we could improve the scenic area's environment and tourists' visiting experience.
Which of the following would be your action(s) in a tourist attraction?
This bar chart shows the way people treats garbage in a scenic area. Most choose to throw their rubbish in the bin (268 out of 281). It is obvious that many people are willing to use garbage cans, so a lot of people would use our biological garbage can, if it is erected in a scenetic area.
Among the tourist attractions you have been to, do you consider plastic pollution a relatively severe issue?
This pie chart reflects the public perception of the severity of plastic pollution. 27% of the respondents think that plastic pollution is often very serious, and another 61% thinking that it is sometimes serious. With a total of 88% of people considering plastic pollution as an issue in tourist attractions, our hypothesis that plastic pollutions in remote tourist attractions is severe is verified by the public. It supports the importance of our trash can, which would help to relieve plastic litterings.
Among your traveling experiences, have you ever had an experience that was impacted by plastic pollution?
This question reflects the extent to which visitors' experiences are affected by plastic pollution. 82% of respondents believed that plastic waste affected their traveling experience in some ways, and 39% of them believed that plastic pollution seriously ruined their mood when traveling. Only 3% of respondents said plastic waste pollution did not affect their experience of play. Therefore, once our trash can is put into use, most people would use it.
This question reflects the respondents' attitude of the extent to which China needs to strengthen environmental protection in tourist attractions. Among the 281 answers, respondents rated 4.49 out of 5, generally agreeing that China urgently needs to strengthen environmental protection in scenic spots, which is consistent with the aim of our project, strengthening our goal of creating the trash bin.
Outcome of the the survey: Verified that our project will be supported by the general crowd
From experiences disseminating our surveys, we verified that most people would accept our trash bins, as most people use garbage bins in tourists sites, agree that plastic pollution problems are severe, and believe that regulations should be set to reduce plastic littering. They also have a relatively high acceptance rate of synthetic biology, showing that our project is likely to be accepted.
Wasted plastic bottle left on a beach in Hainan, China. Photo provided by Doudou Tian, a participant of our public survey.
IMPROVE: Interview with prof. Luo Liu
“Protein expression and PET degradation should be separated into two reactors.”
- Interviewee: Luo Liu, a professor at the Beijing University of Chemical Technology.
- Purpose: to find opportunities for collaboration as well as to seek suggestions and guidances on our lab practices and project.
Interview with Prof. Luo Liu.
Q: What suggestions will you give to our project, regarding the overall design?
A: You need to think farther than the technical part of degrading PET into terephthalic acid and ethylene glycol. The two monomers need to leave the environment in some ways, such as by using them up as carbon sources, or creating motivations for the local people to transport them to factories. The second solution would also work, because selling TPA and EG yields a much higher profit than selling PET itself, whose price is gradually decreasing over these years. Therefore, degrading PET creates motivations for the locals to recycle as TPA and EG are more expensive.
Q: What suggestions will you give to our lab practices and experiment designs?
A:
- When testing for the LCC protein expression using a protein gel, remember to use a negative control – test E. coli without the LCC enzyme – in order to prove with more solid evidences that our experiment led to the expression of LCC enzyme not found in other E. colis.
- 2.Use different amounts of IPTG for protein expression induction. Use 0.1, 0.2, 0.3, 0.4, and 0.5 mMol/L, in order to find the optimum balance for enzyme degradation and bacteria growth.
- Protein expression and PET degradation must be done at different conditions. The culturing of the E. coli needs to be set at 30 degrees, as it is their optimum living condition. During degradation, the temperature should be set to 70 – 80 degrees. The LCC enzyme works best at this temperature, because it is an enzyme extracted from thermophilic bacteria. In addition, PET reaches the glass transition temperature (Tg) and becomes amorphous at 70 degrees, which enables more contact with the enzymes and prompts faster degradation.We could simply heat up the reactor to 72 degrees when we want to transition from bacteria cultivation to the degradation phase. This kills the E. coli, thus releasing the LCC enzymes for degradation.
- We should filter the proteins into a separate space for degradation while continuing to use the enzyme in an reactor. LCC enzyme is very stable and could work without being inside the E. coli. We should use special materials to attach the enzyme onto the reactor’s surface, and filter the LCC proteins into another space where PET is stored for degradation to happen. Thus, when collecting TPA and EG from the bin, the enzyme attached at the reactor can remain and be repeatedly used for the next round of degradation.
- When enzyme activity is low, PET will not be completely degraded to monomers. Instead, it will become dimers and heterodimers, which impacts recycling efficiency, as the heterodimers and dimers are much more soluble than the monomers, and as a result, creates challenges during the recycling process. You should be aware of such conditions and avoid heterodimers and dimers.
- Apart from LCC, TFA and PETase can also degrade PET. Comparing data from our project to other enzymes would be a robust proof of our LCC enzyme’s success.
Outcome of the interview: Improved several parts of our project, including experiment design and hardware design
Prof. Liu suggested that we should go beyond degradation itself and told us that EG and TPA are more expensive than PET itself. We incorporated this idea into our business model, where we talked about how our project helps to reduce littering and degrades plastic, and at the same time, helps local people in remote areas to benefit from selling EG and TPA. This establishes a closed cycle from creating PET to degrading PET, recycling them, and recreating PET bottles through the recycled EG and TPA.
Prof. Liu’s suggestions on how to degrade PET while still preserving the enzymes are readily incorporated into our hardware design. We separated the hardware into two reactors accordingly. One is a cultivator that promotes bacteria growth. Some bacteria will then be transformed into a degradation bin which heats to 72 degrees that kills the bacteria and releases the enzymes, starting the degradation process.
Based on prof. Liu’s suggestions on lab practices, we tried 0.3 mMol/L of IPTG for protein induction, which averaged the IPTG range provided by prof. Liu. Taking prof. Liu’s suggestions, we also used a negative control of another irrelevant E. coli when running the protein gel and discovered that indeed LCC protein expression is only found in our specially manufactured E. coli. We also intend to test the degradation rate of PETase to compare with our results, but due to the pandemic, we had limited time to conduct our lab, and did not have time to create such comparisons. To eliminate the incomplete degradation issue, we would use a linker (see Engineering) that connects our LCC enzyme with a MHETase enzyme, in order to eliminate the existence of dimers and heterodimers.
