The research, development, and launch of the new product require a lot of background research and market research. To investigate the public's awareness of plastic waste, we conducted a questionnaire survey about the general public's understanding of plastic on Chinese social media platforms (mainly WeChat).

Finally we received 402 results from different age groups. Most of them are 19-45 years old. In terms of rating their frequency of using plastic, the average point is about 7.5 out of 10 which is relatively high. Among them, the highest grade is for people over 66 years old, scoring 8.43. Surprisingly it seems that elder people use plastic frequently in their daily life. However, only half of the respondents are aware of the importance of sorting garbage and reducing plastic use. Generally speaking, people's understanding of sorting waste, recycling plastic, and degrading plastic is weak and lacks a clear conception.

Through our statistics, 73.91% of people from age 46-65 have the habit of throwing away the garbage after sorting it. In the group of people under 45 years old, half of them will sort trash depending on their mood or even through it arbitrarily. Thus, it will be very necessary to reinforce education on garbage disposal for this generation.

According to the result in figure 4, 59% of all respondents have the intention of reducing their plastic use in daily life. However, 41% of them are still not aware of the problem. In addition to increasing public awareness of environmental protection, we shall also produce other plastic substitutes or solutions to recycle the plastics in the meantime to decrease the plastics waste issue.

Of all respondents, 157 people (39%) were completely unaware of how plastics degradation today. Bio-degradation has the highest acceptance and awareness of the three most common plastic degradation technologies available today. This reflects the promising future of the biodegradable plastics industry.

Regarding the public opinions of this issue, 281 (70%) identified lacking awareness of environmental protection as a problem in hindering the success of plastic recycling campaigns in the general society. This is closely followed by the issue of low policy implementation, which was also recognized as a problem by 233 (60%) respondents. Third place is the single means of recycling, with 206 (51%) respondents citing a single mechanism of plastic recycling and degradation at this stage. Lastly, technical problems and high costs in recycling and degradation were cited by 177 and 182 respondents, respectively.

(1) People frequently use plastic products in their lives, but only some people have the intention of reducing the use of such products.
(2) There commonly exists a lack of knowledge about recycling and degrading plastics. This makes us realize that it is essential to publicize, popularize and promote the importance for all to participate in the campaign of reducing the use of plastics and pay attention to plastics degradation topic.
(3) The low level of policy implementation is also a more prominent issue. Cooperation with the government shall be an effective way to spread the message and implement environmental policies.

Our team went out on the street and interviewed random people. The offline interview is different from the online questionnaire survey, rather than collecting some data results to reflect some outstanding situations, we hoped to communicate with the general public face-to-face and listened to their real thoughts on our topics. Thus most of the questions we set were open questions with the intention of obtaining different views from the online questionnaires so as to complete our social research survey.
Took a middle-aged man we interviewed, for example, he shared with us his habit of using plastic in daily life and his suggestion that it shall start from the root issue by reducing the use of plastic, even to control the production of plastic products as much as possible, and in the meantime to develop new materials to replace plastic. We were very impressed to find that some people do care about and have their opinions in this regard.

At the same time, we interviewed an elderly person. She said that she did not know much about plastic, but she knew that reducing the use of plastic is very important for protecting the environment. Through the interview with her, we realized that even though the whole society promotes the sense of reducing and sorting plastics, still many people have rare relative knowledge which made me wonder if we could focus more on the education of relative scientific knowledge, and it also drew our attention to the elder group.

On July 27^th, we interviewed Dr. Chen from the School of Environment and Resources, Zhejiang University. We learned pieces of knowledge in 3 big aspects through this interview, which are the effects of PET plastic itself and degraded substances on the soil environment, the methods and challenges for the ecological PET degradation process, the possibility of commercializing our experimental outputs.

Dr.Chen introduced, PET plastic affects the aggregation of the soil so that it decreases, and the bulk density also decreases. The decrease in bulk density will improve the permeability of the soil, which is a positive effect. But PET plastic also affects water saturation in the soil, thus affecting the water cycle on land, which is a negative effect. For the soil itself, when plastic enters the soil, it can add dissolved organic matter substance to the soil and promote the accumulation of polymeric humus. However, if plastic adsorbs harmful chemicals and heavy metals, it will change the characteristics of bacterial antibiotic resistance. Meanwhile, PET plastic may influence animals and plants in a negative way. For animal bodies, the accumulation of PET plastic in the animal body will accumulate and then pass along the food chain, which will be harmful to the health and life of trophic levels. For plants, the soil is an essential carrier. If soil contains micro-plastics, the substances converted to and from plants will also include micro-plastics, affecting plant growth and normal seed development thus reducing germination rates. For microorganisms, PET plastic has an inhibitory effect on their growth, which leads to a decrease in the ecological function of the whole soil.
Through Dr. Chen's sharing above, we enriched our cognition of PET. It can be concluded that plastic molecules may positively impact the soil environment at low concentrations, but still, they will be harmful to the soil environment at high concentrations. And to prevent the negative impact, Dr.Chen furtherly explained that degraded plastic molecules have an improved effect on soil. Because PET plastic can be broken down into small molecules that can be used as a carbon source, resulting in a significant increase in the conversion of carbon and nutrients in the soil. In the other word, our research is necessary and responsible to the environmental protection, especially beneficial to the soil.

A. The extent to which PET plastics can be emitted
PET plastic degrades into small molecules of MH1T, glycol terephthalic acid, carbon dioxide, and water. Dr. Chen said that after degradation into small molecules of MH1T, microorganisms could use it, and the impact on the environment is significantly reduced. In 2016, Japanese scientists isolated a strain of bacteria near Osaka that can break down PET plastic, which can digest and use MH1T and mitigate the environmental impact of PET plastic. However, if we want to reach a point where there is no environmental impact, carbon
B. Benefits of PET degradation enzymes for PET degradation
The traditional way of degrading plastics is complicated and causes secondary pollution. These problems can be avoided if synthetic biology is used to explore the degradation of plastics. Degradation enzymes can degrade plastics into micro-plastics, which can be metabolized into carbon dioxide and water, and these products are not harmful to the environment.
From the perspective of resource utilization, using biological methods, that is, enzymes or microbial degradation, and degradation of plastics can reduce disposal costs and avoid secondary pollution..
C Challenges of PET bio-degradation
There are totally four challenges of PET bio-degradation in Dr. Chen's view. The first point is the interaction between unbalanced enzymes and substrates, which are required in reactive degradation. The second point is that thermal stability is more challenging to achieve. The third point is that the efficiency of catalysis at higher reaction temperatures is too low. The fourth point is that the oligomer degradation intermediates cause the inhibition effect of the product.

According to Dr. Chen, there are four ways to reduce PET plastic. The first point is that the recycling process should be economical in terms of steps, rather than using physical or chemical recycling methods with high energy costs. The second point is to simplify the recycling process. The physical recycling process requires sorting, drying, stretching, plasticizing, etc., while chemical recycling uses chemical reactions to degrade. These methods are very complex. Simplifying the recycling steps can reduce costs. The third point is to improve recycling efficiency surely. The fourth point is to enhance the performance of the recovered product so as to improve its economic value.

Also, Dr. Chen added that degradation enzymes still have many limitations because the conditions of degradation are very demanding. The degradation process must consider the degradation conditions such as temperature, PH degree, the degradation container, etc. Moreover, the degradation time can be very long with the current efficiency of degradation enzymes. These factors lead to the limitation of the use of degradation enzymes in terms of site and object. After this conversation, we acquired many professional insights and had more thoughts on the directions of our product development.

To consult about the implementation of our project, we managed to contact Dr. Li for an online interview.

After explaining our project and outlining the business plan, Dr.Li evaluated our work as a feasible way of degrading PET and earning profits. Explicitly, in the aspect of our total approach, we claimed that there are two ways we can run our business: the first one is ODM, which is to produce and consume our products on our own; the second one is OEM, which is to sell the patron of our products, to cooperate with other firms to produce and sell the products. Dr. Li believed these approaches will both work well in running the business. Therefore, we decided to use both approaches to run our company.
Besides, Dr. Li strongly recommended that we shall sell our products to companies instead of individual consumers since in his view, actually there shall be little demand from individuals to use our products.
Additionally, Dr. Li encouraged us to put ourselves in consumers' shoes and find their benefits by using our products. In this case, companies will have more tendency buying our products. For instance, some big companies may degrade and recycle PET to maintain a good company image, thus they are willing to buy our enzymatic degradation products. Dr. Li suggested we could learn experiences from a company called Cabos, which is also a company that uses enzymes to degrade plastic and recycle them. Moreover, the company uses its recycled plastic material to produce new and environmentally friendly products and sell them to earn profits.
Given the different policies and situations in each country, we asked Dr. Li about the development phase and companies related to enzymatic degradation in our country. According to Dr. Li's sharing, now some domestic academic institutions and research institutes have published research articles on enzymes. Their research purpose is to enhance the activity of enzymes and improve reaction efficiency. Dr. Li mentioned that the current technology also has certain limitations. Because the temperature of the enzyme is relatively high, it will consume more energy when used. Secondly, at present, the white pollution existing in the natural environment can no longer be degraded and recycled in this method.
Finally, we sought Dr. Li's opinion on whether it is feasible to cooperate with the governments, Dr. Li thought it is a good idea of strengthening our company since, in recent years, the government has attached great importance to the recycling and degradating plastics. It will be possible for us to receive support from the government.

On July 28^th, 2022, we conducted an interview with Prof. Han, mainly focusing on four parts including the degradation process of petroleum-based PET and bio-based PET, its challenges the problems encountered in the degradation of PET, and the future development of biological decomposition.

Prof. Han introduced two kinds of PET for us one is called bio-based PET, which is produced by green plants and continuously produced by themselves; another one is called petroleum-based PET, the raw material of which is not renewable, because of its being extracted from fossil and petroleum. The two materials themselves are formed in a very long time, which can reach thousands or even tens of thousands of years.
Why does society prefer the bio-based one? According to Prof. Han's opinion, the main reason is that social demand comes from the process of obtaining raw materials. Bio-based is more environmentally friendly, while the transformation process of petroleum-based refining is more harmful to the environment. Bio-based is mainly through the extraction of straw from agricultural products. Although the cost of this process is relatively high, the demand for carbon dioxide emissions is not large in general. Anyway, eco-friendly products are easier to be accepted by the general public.
For both bio-based and petroleum-based PET, the difference between them after degradation is not apparent, because the chemical molecules are the same. For the latter one, Prof. Han replied, in fact, the degradation after the recyclability mainly depends on the form of degradation. If the chemical or physical degradation method is used, the conditions will be more extreme, and more reactions will occur, resulting in a lot of impurities in the final synthesized plastic.

The first question in the second part was what are the benefits of using PET degrading enzymes to degrade PET? Faced with such a question, Prof. Han firstly explained the PET decomposition process and he added that actually PET enzymes were just found in recent years. PET could be recycled by re-production after degradation although its transparency is not that good. After physical and chemical reactions, the products are difficult to be purified. So, we can use the biological method that is PET enzymes, which is a relatively mild method that makes it a more common way around the world.
Next, in terms of the time to degrade a plastic bottle, Prof. Han mentioned that actually, we will not degrade the whole bottle directly. Only when it is physically breakdown into particles in advance enzymes can degrade. Ather the whole plastic bottle is broken down into micro-plastics, Prof. Han assumed, probably it still requires weeks to finish the whole degradation.
Regarding the toxicity of the degrading products, he thought that the enzymes and the raw materials used in the process are of low toxicity to humans and no harm to the environment either. To conclude, theoretically the final products after our enzyme-degradation process shall be none toxic.
We also were curious about sustainable PET degradation enzyme activity duration during the degradation process. Prof. Han said the duration to maintain its activity will depend on the reaction conditions since PET degradation enzymes are proteins. It even will still be active even after a few years, although its resistance to temperature is higher. But if we put it in a container where the temperature is higher than 37, the activity will decrease, in general.
He added that the activity of the enzyme molecule is the first requirement of the degradation enzyme in order to decompose plastics. Though the enzyme will naturally form from microorganisms, their metabolism is very slow, and need to slowly decompose for catching up with the speed of their own energy supply.

"Can we use the computer to locate the mutagen site?" The professor said that there is a lot of research focusing on this question, and researchers can find out the mutagen site by analyzing it on the computer and calculating. It can be improved by artificial intelligence to screen and analyze, even predict the activity of enzymes from one amino acid to another amino acid. He confirmed the feasibility to take the advantage of computers to find the optimization plan for our product development.