(I) Plastic Lifecycle

1. Background

1.1 The Broader Context of Plastics and Their Implications

Plastics, particularly polyethylene terephthalate (PET), have become indispensable materials in modern society due to their excellent mechanical properties, chemical stability, and low cost. They are widely used in packaging, textiles, electronics, and numerous other fields. However, their massive production and consumption have led to severe environmental issues, especially the persistent escalation of “white pollution.”

“White pollution” is a vivid term describing environmental contamination by non-biodegradable single-use plastic waste—such as plastic bags, food containers, bottles, and packaging films. Often discarded carelessly or improperly treated after use, these plastics persist in natural environments for centuries due to their resistance to natural degradation. They not only degrade soil fertility and hinder crop growth; but also form massive garbage patches in oceans. Marine life ingests them, leading to death or accumulation in the human body through the food chain, posing long-term and profound threats to ecosystems and public health.

Global plastic production continues to surge, projected to reach 1.32 billion tons by 2060, with PET accounting for a significant share. Over the past seventy years, the world has generated approximately seventy million tons of plastic waste, collectively termed white pollution.

Traditional disposal methods like landfilling and incineration not only consume vast land resources but also release toxic gases (such as dioxins) and microplastic particles, further exacerbating pollution in the atmosphere, water bodies, and soil, creating a vicious cycle.

Against this backdrop, biodegradation emerges as an environmentally friendly, mild-condition, low-energy-consumption approach, offering a crucial solution to plastic pollution. Particularly, constructing engineered bacterial strains through synthetic biology to achieve efficient PET degradation and resource conversion of its products (such as ethylene glycol EG and terephthalic acid TPA) not only alleviates environmental pollution but also transforms waste into high-value-added chemicals, driving the development of a green circular economy.

Therefore, developing efficient and sustainable PET biodegradation and upcycling technologies has become a frontier topic at the intersection of environmental science and synthetic biology, holding significant scientific importance and application potential.

2. Policy

2.1 Overview of Policy Background Including the 14th Five-Year Plan

The Action Plan for Plastic Pollution Control during the 14th Five-Year Plan Period (hereinafter referred to as the “Plan”) is a guiding document jointly issued by the National Development and Reform Commission and the Ministry of Ecology and Environment in 2021. It serves as a comprehensive policy framework for China's response to plastic pollution, promotion of “waste-free city” construction, and advancement of ecological civilization during the 14th Five-Year Plan period (2021-2025).

This Plan represents an upgrade and deepening of the previous “plastic restriction order,” shifting its core objective from a single ‘restriction’ (e.g., limiting single-use plastic products) to systematic “management.” It aims to establish a comprehensive management system covering the entire chain of plastic products—from production, circulation, consumption, recycling, to final disposal.

The Plan proposes three major action directions, commonly referred to as “Ban, Reduce, and Recycle”:

1. Actively Promote Source Reduction in Plastic Production and Use

(1) “Ban”: Prohibit the production and sale of certain single-use plastic products, including ultra-thin plastic shopping bags and disposable foam tableware.

(2) “Reduce”: Promote the reduction of non-degradable plastic products in key sectors such as retail, catering, e-commerce delivery, and accommodation/convention services, while promoting recyclable and easily recoverable alternatives.

2. Accelerate the standardized recycling and disposal of plastic waste

The core focus is “Circularization,” meaning recycling. Strengthen clean recycling and regeneration of plastic waste, significantly increasing the proportion of plastic waste converted into resources or energy. This includes improving urban and rural waste sorting and recycling systems, and supporting the development of the plastic recycling industry.

3. Intensify Plastic Waste Cleanup and Remediation in Key Areas

Conduct targeted cleanup campaigns in areas with severe plastic pollution, such as rivers, lakes, seas, tourist attractions, and rural regions, to curb the spread of “white pollution.”

2.2 Government Research Report

See Attachment 1

3. Youth Initiatives

3.1 World Games Volunteers

As young students at University of Electronic Science and Technology of China and members of the “iGEM Competition Team,” we recognize that addressing global environmental challenges is not only scientists' responsibility but also our generation's mission. Beyond exploring cutting-edge synthetic biology solutions to plastic pollution in laboratories, we actively engage with society by combining scientific spirit with volunteer service, dedicating ourselves to the frontlines of urban environmental protection.

Recently, core members of our team had the honor of participating in the Chengdu waste sorting “Snap and Share” volunteer initiative, “World Games: I'm In, Sorting Together,” and received volunteer service certificates from the Chengdu Environmental Protection Volunteer Service Federation. This recognition not only encourages our personal dedication to volunteerism but also affirms our philosophy of “serving society through technological practice.”

Stepping out of the ivory tower, we delved into communities and streets, documenting, monitoring, and promoting waste sorting through methods like “snap-and-share.” With youthful passion and ingenuity, we transformed waste sorting—a seemingly minor yet crucial task—into a trend-setting behavior that champions “low-carbon living as a new lifestyle.” This vividly embodies the “whole-society participation” principle advocated in the “14th Five-Year Plan Action Plan for Plastic Pollution Control.” Aligned with our iGEM project “Biodegradation and Upcycling of PET Plastics,” we have paid particular attention to the fate of recyclables—especially plastic waste—through our volunteer work. What we educate citizens about extends beyond “placing plastic bottles in the blue bin” to the immense potential of the “circular economy” behind it—these materials need not be the culprits of pollution but can be transformed into high-value resources through advanced biotechnology. Our volunteer work bridges the gap between the sophisticated concepts of “biological degradation” and “high-value conversion” in the laboratory and tangible, accessible, and participatory green practices for the public.

This volunteer service certificate bridges our scientific exploration in the lab with environmental action in society. Moving forward, we remain committed to the belief that “technology for good.” We will continue to tackle plastic pollution with innovative solutions on the iGEM international stage while staying rooted in China, using volunteer service to ignite environmental passion in more people.

(II) Plastic Recycling

1. Urban Processing Stream

1.1 Overview:

Every day, plastic bottles, packaging bags, and food containers discarded from our hands quietly embark on a long and winding journey. At birth, they symbolized modern life—lightweight, durable, and inexpensive—serving to wrap food, hold beverages, and protect goods. Yet once tossed into trash bins, their value plummets, seemingly transforming overnight from “valuable materials” into “useless debris.”

Some of this plastic waste, if fortunate enough to land in recycling bins, might gain a second life through careful sorting, cleaning, and reprocessing—becoming recycled fibers or low-end plastic products. More often, however, they remain contaminated with grease, labels, and impurities, becoming the most vexing challenge in urban waste management systems. They may be transported to compacting stations, mechanically compressed into blocks, and shipped far away: either fed into incinerators, where they convert into energy while releasing pollutants; or buried in landfills, silently accumulating underground for centuries, gradually breaking down into microplastics that quietly infiltrate soil and water sources.

This is the life cycle of plastic—from petroleum essence to societal and environmental burden. Its disappearance is not true vanishing, but a prolonged exile from our sight to an invisible yet tangibly distant realm. Recognizing the unsustainability of this “final chapter,” our synthetic biology team—specializing in PET biodegradation and high-value conversion—decided to step out of the lab. We visited waste compaction plants, landfills, and incinerators to uncover the true fate of plastic waste and seek answers for our next research frontier.

1.2 Street Interviews

This street interview campaign served as the first stop in our urban research, aiming to gauge public awareness of plastic degradation challenges and assess acceptance and perceptions of our project—“converting PET plastic into high-value products (such as perfume, animal feed, and traditional Chinese medicine ingredients) through synthetic biology.”

We focused on two key areas: First, the counterintuitive aspect—does the idea that degraded plastic can become everyday high-value products defy public common sense? Second, the recycling-to-value aspect—are consumers willing to pay for “recycled plastic” products? Does the eco-friendly attribute justify a premium price?

Core findings and insights from this street interview:

(1) Significant gaps in public knowledge about plastic degradation products

The vast majority of respondents lacked understanding of the specific products resulting from plastic degradation. High-value conversion pathways like “plastic-to-perfume” were perceived as counterintuitive, highlighting strong potential for science communication.

(2) Environmental attributes can justify premium pricing, but price sensitivity exists

Consumers generally accept paying a small premium for eco-friendly concepts. However, acceptance drops sharply if the premium is excessive (e.g., doubling the price). Environmental attributes are better positioned as “added value” rather than core selling points.

(3) Technical feasibility and cost are key acceptance factors

While respondents did not understand technical details like “magnetic enzyme immobilization” or “engineered microbial metabolic pathway modification,” they expressed strong interest in “low-cost, high-efficiency, and recyclable” processing methods, viewing these as fundamental to the project's sustainability.

1.3 Field Research at Wuhou District Urban Resource Processing Center

Before visiting the Wuhou District Urban Resource Processing Center, we envisioned a scene of automated sorting lines operating efficiently, with plastic bottles and packaging films each in their designated places, and recycled resources flowing smoothly... In reality, we stood in the spacious, well-lit exhibition hall facing an elaborate, large-scale sand table model depicting the complete “unloading-sorting-recycling” workflow. It showcased intelligent sorting, leachate treatment, and odor purification systems—all fully integrated.

However, the manager candidly shared: While the center was designed with foresight and reserved interfaces, end-of-pipe solutions alone cannot solve recycling challenges. With inadequate front-end sorting and incomplete recycling chain integration, their core tasks remain “volume reduction and sealed transfer.” True source separation and recyclable material sorting haven't been achieved—PET bottles, takeout containers, and plastic bags still enter mixed and get compressed together.

Though we didn't witness actual sorting operations, several critical issues became clearer:

(1) “Low-value waste plastics” lack outlets: Takeout containers and dirty plastic bags, deemed unprofitable due to high cleaning costs and low recycling value, are rejected by processing plants and simply baled for transport—effectively becoming materials “reclassified for disposal.”

(2) The “dual networks” remain isolated, with integration still a work in progress: Disconnects persist between sanitation systems and recycling infrastructure. Compaction plants can compress and transfer waste, but they cannot replace sorting or substitute for recycling.

(3) Technology that fails to “embed within the system” struggles to gain traction: Even with perfect PET-degrading enzymes and conversion strains, without complementary sorting, pre-treatment, and policy support, the most advanced biotechnology cannot be truly implemented.

Thus, we continually ponder: How should technology address the bottlenecks at compacting plants?

This field research has made us acutely aware: A technology's value lies not in its “advanced” nature, but in its ability to precisely address the most genuine pain points within the system. The current state of this compacting plant precisely points to the direction where our synthetic biology technology can continue to evolve and upgrade:

(1) Addressing “imperfect” substrates—developing more resilient enzyme systems

The materials circulating in compression plants are predominantly mixed, contaminated, and non-crystalline everyday plastic waste. Therefore, future efforts should not solely focus on optimizing metabolic models for downstream conversion. We must also concentrate on modifying PET-degrading enzymes to develop systems capable of processing mildly contaminated, mixed PET waste without relying on “pure substrates.” Enhancing their thermal stability, acid tolerance, and resistance to impurity interference will enable them to maintain activity in environments closer to real-world waste processing conditions—such as pH fluctuations and the presence of other contaminants.

(2) Overcoming the “Conversion Challenge” Bottleneck—Designing More Efficient Strain Chassis

In practice, PET degradation products (like TPA) are difficult for microorganisms to absorb and convert, severely limiting subsequent high-value utilization. Future efforts should involve gene editing to strengthen transport systems and improve cell membrane permeability to TPA.

(3) Preparing for the Future—Adapting Technology to Systems and Exploring “On-Site Pretreatment” at Compaction Stations and Transfer Points

We recognize that biological treatment technologies must seamlessly integrate with existing waste management workflows (compaction, transportation, temporary storage). Therefore, future project implementation should explore modular, mobile small-scale biological treatment units designed for integration into compression stations or transfer facilities, aiming to achieve PET volume reduction and pre-conversion during the transportation phase.

Though we did not witness the “actual scene” of sorting lines, we observed the ‘reality’ of plastic waste processing. This experience dispelled our romanticized notions about technological application. Consequently, we designated the Wuhou District Urban Resource Processing Center as our first stop for “on-site lessons in plastic waste processing,” followed by visits to landfills and incineration plants.

1.4 Summary of Sangzhi County Landfill Research: Anchoring the Grassroots Adaptation Direction for PET Technology

As a critical intermediate link in our full-chain investigation—“compaction plant → landfill → incineration plant”—we conducted on-site visits to the Sangzhi County landfill, witnessing grassroots waste treatment practices. We also engaged in in-depth discussions with Director Xiang Yong of the County Environmental Sanitation Bureau to identify the real challenges in county-level plastic waste management. This dual approach of “field observation + frontline interviews” enabled us to transcend laboratory thinking, identifying practical implementation directions for PET biodegradation technology that “align with existing grassroots infrastructure while addressing real-world pain points.”

(1) Landfill Site: A Practical Reference for Grassroots Biotechnology

Entering the Sangzhi County landfill revealed a far cry from the stereotypical image of end-of-pipe waste disposal. Instead, it showcased a systematic, controllable modern treatment system. The first thing to shatter our preconceptions was the “precision-controlled” management scene: all landfill areas were tightly covered with black HDPE impermeable membranes. Methane gas was centrally collected via a negative pressure system (for subsequent power generation), leaving the site virtually odor-free. At the leachate treatment area, real-time monitoring screens display ammonia nitrogen and hydrogen sulfide data uploaded to the provincial environmental platform every few hours, enabling dynamic oversight of pollution risks. This reveals that grassroots waste management has long transcended “extensive landfilling,” entering a new phase of “resource reuse + precise pollution control.”

What truly captivated us was the nitrification tank within the leachate biological treatment system. Aerators at the tank bottom continuously supplied oxygen, while colonies of light brown nitrifying bacteria gradually converted highly toxic ammonia nitrogen—at concentrations 30 times higher than domestic sewage—into less toxic nitrate. Ultimately, this process transformed the waste into nitrogen gas and compliant clean water. This process leaves no chemical residue and costs significantly less than chemical methods, relying solely on the natural metabolic capabilities of microorganisms. This scene acts like a mirror, reflecting the potential of our PET technology and resonating deeply with us:

They degrade ammonia nitrogen with bacteria; we break down PET with enzymes and convert EG/TPA with engineered microbes. They create optimal conditions for microbial communities through “aeration + glucose addition”; we enhance enzyme and microbial stability via magnetic immobilization and gene editing. Biotechnology isn't a distant concept confined to laboratories—it can be a mature solution already operating reliably at the grassroots level.

However, the landfill manager also admitted frankly: Sangzhi County has yet to implement waste sorting. The compressed waste is still primarily incinerated with landfill as a secondary option. Plastics are often mixed with kitchen waste and construction debris for processing, and the sorting facility is still in preparation. This reality directly addresses our project's core concerns: Can PET technology process mixed plastics containing impurities if waste isn't thoroughly sorted? If grassroots infrastructure upgrades are slow, can the technology be cost-effectively integrated into existing processes? The nitrification tank pilot has provided partial answers: Biological methods can tolerate complex contaminants, align with grassroots budgets, and integrate into existing systems—offering clear benchmarks for our technological optimization.

The project lead candidly acknowledged Sangzhi County's current lack of waste sorting. Compressed waste is primarily incinerated with supplementary landfilling, while plastics are mostly mixed-processed. The sorting facility remains under construction—this absence of front-end sorting directly contributes to the ineffective recycling of vast plastic volumes.

Yet this directly addresses our project's core concerns:

If waste isn't fully sorted, can biotechnology process mixed, impure plastics? If grassroots infrastructure upgrades are slow, can our solution remain low-cost, efficient, and compatible with existing systems? Can it integrate into current management workflows like leachate treatment without disrupting existing systems?

Practical testing of the nitrification tank has provided partial answers:

① Biological treatment tolerates complex contaminants

② Suitable for grassroots settings, stable and cost-controllable

③ Integrates into existing systems without requiring overhaul

(2) Interviews with sanitation departments: Real challenges and needs in county-level plastic processing

See Attachment 2

(3) Key takeaway: Clear-eyed awareness outweighs blind optimism

This dual investigation and interview with “landfills + sanitation departments” served as a pivotal bridge in our end-to-end research: Nitrification tanks purifying landfill leachate demonstrated the grassroots potential of biological methods, while sanitation department bottlenecks and needs clarified the value and relevance of our current technology.

We recognized the vast gap between “laboratory” and “reality,” understanding that the pure PET substrates in labs are entirely different from real-world plastic waste mixed with labels, caps, and residues. The true significance of our current technology lies in validating the feasibility of a scientific pathway; bridging this to practical application requires a long journey of engineering development.

We also learned that cost is the core factor in grassroots waste management decisions. A processing cost of approximately 200 yuan per ton means any new technology must face a rigorous economic test. This led us to reflect that our current focus should be on optimizing core technical metrics (such as enzyme activity and conversion efficiency) to reduce potential future costs.

Simultaneously, we gained a precise entry point for “concept validation”: the director's suggestion to start with scenarios like tourist attractions and commercial districts—where PET bottle sources are singular and concentrated—proved highly enlightening. This shows that technology adoption doesn't necessarily require overhauling the entire waste treatment system from the outset. Instead, it can serve as a “refined, high-value” supplementary module, demonstrating its unique value within specific contexts.

1.5 Field Research at Everbright Environmental Energy (Zhangjiajie) Co., Ltd.: Calibrating the Implementation Path for PET Biodegradation Technology at the Frontline of End-of-Life Processing

As the terminal segment of our comprehensive “waste compaction plant - landfill - incineration plant” chain survey, we not only visited Everbright Environmental Energy (Zhangjiajie) Co., Ltd.'s “garden-style facility” but also conducted an in-depth thematic interview with Manager Yi Xun from the company's Safety and Environmental Department. — From observing the entire waste incineration process on-site, to probing technical details and real pain points in PET plastic treatment, to exchanging practical implementation suggestions, this helped advance the project from “laboratory concept” to “industry-adapted solution.”

(1) On-Site Observations: The “Balance of Efficiency and Environmental Protection” in Modern Incineration Plants

The stereotypical image of incineration plants as “dirty, messy, and smelly” was completely shattered upon entering the facility. The waste undergoes a fully automated, end-to-end process from arrival to final treatment: → ash utilization." The entire process is automated. The central control room's large screen displays real-time key data: dioxin emission concentration < 0.05 ng TEQ/Nm³ (during certain periods < 0.01 ng TEQ/Nm³, exceeding the EU standard of ≤0.1 ng TEQ/Nm³). In the crane control room, mechanical grapples precisely handle fermented waste, while a spray deodorization system eliminates noticeable odors on-site.

Manager Yi Xun explained that the plant employs internationally mainstream mechanical grate furnace technology with a daily processing capacity of 800 tons. Compared to cement kiln co-processing, this approach focuses specifically on municipal solid waste treatment while reliably generating electricity and supplying waste heat steam to nearby hotels. This “energy recovery + resource utilization” transformation practice vividly demonstrates the “balance between efficiency and environmental protection” in end-of-pipe treatment, offering a practical reference for exploring the complementarity between PET technology and incineration systems.

(2) In-depth Interview: Addressing PET Processing Pain Points and Technical Implementation Recommendations

See Attachment 3

(3) Project Feedback: From Industry Recommendations to Laboratory Optimization Directions

Based on Manager Yixun's insights and research findings, we systematically organized the core takeaways, reflections, and innovative perspectives from this investigation, summarized as follows:

① Key Findings and Enhanced Understanding

a. Modern Incineration Plants Are “Resource Hubs,” Not “Pollution Terminals”

The Everbright Zhangjiajie project demonstrates a highly automated, clean, and resource-efficient waste treatment paradigm: from waste intake, fermentation, incineration, and power generation to flue gas purification and ash brick production, achieving dual outputs of “energy recovery + resource recovery.” PET, as a high-calorific material (approx. 23 MJ/kg), aids in maintaining furnace temperatures during incineration. However, its co-incineration with chlorinated plastics (e.g., PVC) may elevate HCl emissions, necessitating pre-treatment and process control measures.

b. PET Processing Faces Systemic Challenges; High-Value Conversion is the Clear Path

Physical recycling faces degradation cycle limitations, while chemical recycling grapples with energy consumption and purity challenges. Intelligent sorting, low-carbon depolymerization, and high-value conversion (e.g., EG→PEAs, TPA→protocatechuic acid) represent key future breakthrough areas. Our developing “magnetic immobilized dual-enzyme + engineered microbial conversion” technology aligns closely with the high-value pathways identified by experts.

c. Biotechnology and incineration systems possess complementary potential

Biological pretreatment reduces incineration load, while residues (15%-20%) can be returned for incineration power generation to achieve energy recovery; however, engineering challenges such as enzyme cost, non-sterile adaptability, and matching degradation/conversion rates must be addressed.

d. Policy drivers are evident, and the industry is undergoing rapid transformation

① The 14th Five-Year Plan explicitly encourages “chemical recycling/bio-enzyme catalysis”;

Everbright has introduced AI sorting and participated in drafting the Technical Specifications for Chemical Recycling of Waste Plastics, signaling industry advancement toward refinement and high-value utilization.

② Profound Reflection: From “Technological Idealism” to “Industrial Reality”

Previously, we overly focused on “technological advancement” while neglecting “market demand” and “user acceptance.” Experts emphasize: “Don't start with ‘what technology we have,’ but work backward from ‘what the market needs.’” A new technology is not merely a technical replacement but a restructuring of industrial chain value. It must benefit sorting plants, chemical factories, and product users alike to achieve widespread adoption. While incinerators' mechanical grippers may not be cutting-edge, they are “adequate, durable, and low-maintenance”—we too must shift from pursuing “laboratory efficiency” to designing systems that are “affordable for grassroots use.”

③ Innovative Thinking and Future Improvements

Integrated solutions from front-end sorting to back-end conversion: Consider interfacing our biological treatment modules with Everbright's AI optical sorting system to enhance PET feedstock purity. We can explore returning biological treatment residues to incineration for power generation, achieving dual pathways of “material recycling + energy recovery.” Experts have explicitly highlighted enzyme stability under non-sterile conditions as a critical challenge. Once microbial strains demonstrate consistent performance, our next priority should be conducting enzyme activity tests and strain adaptation improvements in real waste environments. Additionally, PEA and protocatechuic acid require certification for bio-based materials and pharmaceutical intermediates. We should proactively engage downstream enterprises (e.g., biodegradable plastic manufacturers, pharmaceutical companies) with laboratory outputs to seek guidance and collaboration. Finally, designing a “visual public experience” module to overcome NIMBY resistance: We can draw inspiration from Everbright's “open tours + empathetic communication” model to create interactive experiences like “plastic bottles turning into perfume.” This approach visually demonstrates the speed and value of biodegradation, enhancing public acceptance.

This visit has made us acutely aware: A technology's value lies not in its sophistication, but in whether it is needed, used, and trusted. As we advance PET biodegradation and high-value conversion research, we will prioritize: market-driven demand, cost-controlled design, industrial chain collaboration, and public communication with value visualization. Only then can our technology truly emerge from academic papers to become a valuable link in the “plastic closed-loop cycle.”

1.6 Plastic Waste Survey at Sangzhi Badagongshan National Nature Reserve: Discovering New Application Directions for PET Technology in Ecologically Sensitive Areas

As a crucial extension of our comprehensive “Plastic Recycling - Urban Processing Line” investigation—spanning urban waste compression plants, Sangzhi County incineration facilities, and now deep into Hunan's Badagongshan National Nature Reserve—we aim not only to trace the “urban final destination” of plastic waste but also to explore technological adaptability in ecologically sensitive zones. Through in-depth discussions with Director Gu Zhirong of the Science and Technology Division at the Hunan Badagongshan National Nature Reserve Administration (also serving as Director of the Green Xiaoxiang Lishui Source Ecological Protection Station), the reserve's pressing challenges—high plastic waste proportion, scattered distribution, and difficult disposal—along with the core need for “on-site processing,” opened new application dimensions “beyond the city” for our PET biodegradation project.

Director Gu's insights helped us transcend the “scale-driven mindset” of urban waste management and confront the unique challenges of ecological scenarios:

See Attachment 4

The value of this interview lies in elevating our PET project from a “supplementary solution for urban end-of-pipe treatment” to a comprehensive “dual-scenario solution covering both urban and ecological environments,” completing the project's “scenario puzzle.” As Director Gu emphasized, “Environmental technologies must serve both ecological conservation and public welfare.” The research in the Eight Great Mountains not only revealed the unique value of technology in ecological zones but also reminded us: true environmental innovation must adapt to both the “scale efficiency” of cities and the “precise safety” requirements of ecological areas. This is precisely the “more comprehensive and actionable” value direction we identified for the project through our end-to-end research.

2. Full-Chain Integration: Using Research as a Mirror to Define the Value Loop at the Laboratory Stage

This systematic investigation of the Everbright Incineration Plant, Wuhou Compaction Station, Sangzhi Landfill, and the national nature reserve has connected the entire chain of plastic waste “collection-transportation-treatment-disposal,” revealing its true landscape. From the “cost sensitivity” at compression plants to the “complex substrates” at landfills, and the “volume reduction and efficiency enhancement” demands at incinerators, end-users' expectations for PET treatment technologies extend beyond isolated technical breakthroughs. They seek a seamless, low-cost, interconnected, and highly complementary solution that integrates into the entire “collection-transportation-transfer-disposal” chain.

These insights did not drive us toward blind pursuit of premature or large-scale technological promises. Instead, they sharpened our awareness of the core mission at the current laboratory stage: to rigorously validate the feasibility of the “PET biodegradation and high-value conversion” technology pathway through small-scale, high-precision experiments, thereby accumulating critical data and directional insights for potential future industrial applications.

The value of this end-to-end research lies precisely in this: it helps us transcend the limitations of “laboratory utopianism” while preventing us from falling into “overly ambitious concepts detached from our current capabilities.” Field visits and in-depth interviews have charted a clear path for future upgrades, ensuring our technological direction remains anchored to genuine industrial needs. Using this research as our compass, we are both advancing concrete optimizations for this year and diligently building a reserve of critical experience for future enhancements. Balancing “grounded present” with “forward-looking future,” we steadily explore a “lower-carbon, higher-value” processing pathway for PET plastics.

(III) Plastic Value Enhancement

1 Project Selection

1.1 Overview

PET plastics are widely used due to their excellent properties, but their non-biodegradable nature leads to severe environmental accumulation. By 2060, global plastic production is projected to reach 1.32 billion tons. Traditional disposal methods like landfilling and incineration are not only inefficient but also exacerbate environmental pollution and carbon emission crises.

As highlighted by the professor we interviewed in their response, all current approaches—whether physical recycling (degradative cycles constrained by feedstock purity), chemical recycling (e.g., alkaline hydrolysis hampered by separation/purification challenges and high costs), or emerging enzymatic recycling (limited by PET crystallinity and requiring efficiency improvements)—face distinct industrialization hurdles. Particularly, most current methods stop at depolymerizing PET into monomers TPA and EG, failing to achieve value leapfrogging. Economic viability remains the core barrier to large-scale adoption. While biodegradation has its drawbacks, it effectively addresses some challenges of physical and chemical recycling.

Through in-depth research, we identified an overlooked yet critical issue: the enzymatic degradation products ethylene glycol (EG) and terephthalic acid (TPA) are not “end products.” EG competitively inhibits PET hydrolases and exhibits microbial toxicity, hindering degradation efficiency; TPA accumulation also impairs microbial metabolism. This implies that simple depolymerization cannot establish an efficient, self-sustaining circular system.

Therefore, mere “degradation” is insufficient—products must undergo “instantaneous conversion.” Our project addresses this critical challenge by employing synthetic biology to not only efficiently degrade PET but simultaneously convert inhibitory EG and TPA into high-value-added products. This approach removes inhibition, enhances efficiency, and creates value. Moreover, our initiative aligns closely with the core principles of the “14th Five-Year Plan Action Plan for Plastic Pollution Control,” which emphasizes “promoting the resource utilization of plastic waste” and “encouraging recyclable, easily recoverable alternative products.” We are not merely repeating “degradation” but practicing a more advanced “upcycling”—precisely the innovative direction encouraged by policy.

Through discussions with Maike Gaocai, we learned that industry's core concerns regarding new technologies revolve around cost, safety, and market acceptance. Our design directly addresses these concerns:

(1) Magnetic enzyme immobilization: Enhances enzyme stability and reusability to reduce costs.

(2) Rigorous biosafety design: We plan to conduct safety validation of engineered bacteria and adopt a “authoritative certification + accessible science communication” approach to directly address biosafety concerns and public skepticism.

(3) Production of high-value products (e.g., PEAs): Transforming waste into marketable bio-based biodegradable materials directly enhances economic viability and drives market adoption.

We fully recognize that groundbreaking innovations often emerge at the intersections of disciplines. We have chosen a path that integrates synthetic biology, enzyme engineering, metabolic engineering, bioinformatics, and materials science. We conduct not only wet experiments but also rationally guide strain design through whole-genome metabolic modeling (dry experiments), thereby enhancing success rates. We focus not only on the technology itself but also explore industrialization pathways and societal acceptance through social practice and corporate interviews.

As one professor noted, coupling diverse recycling methods represents the future direction. Our project embodies this “Bio+” integration approach—not to compete with chemical recycling, but to explore new possibilities where it faces challenges, such as processing complex feedstocks and achieving high-value conversion under mild conditions.

In summary, we selected this project because it transcends a mere competition topic—it addresses genuine societal needs, scientific challenges, and industrial concerns. We aim to contribute an innovative solution from China's youth to the nation's “Zero Waste City” initiative and global plastic pollution mitigation efforts.

2. Project Benefits

2.1 Living Drugs iGEM Theme Exchange

On August 5, 2025, our team participated in Peking University's “Engineered Living Drugs” thematic exchange meeting. We presented our “PET Biodegradation and High-Value Conversion” project (Bio-Remediation Track) in person while coordinating online attendance for remote members. This exchange focused on gaining practical insights in synthetic biology, ultimately identifying technical optimization directions for our project and establishing preliminary collaboration agreements with cross-track teams.

During the “Lightning Pitch” session, Jilin University's iGEM team (Space Track) captured our attention with their “Space Sleep Bacteria” project. This team engineered probiotics to synthesize melatonin, precisely releasing it through temperature- and sound-controlled systems to address astronauts' sleep challenges in space. Despite competing in different tracks, our needs proved highly complementary: Jilin University's team possessed exceptional graphic design capabilities but lacked experience in science communication implementation; our team had accumulated practical methods in community outreach and gamified science education, while urgently needing visual mediums to optimize communication around “PET degradation” technology. During the tea break, our in-depth discussions led to a consensus: jointly developing a synthetic biology science picture book. The story will center on the magical adventures of our two teams' IP characters within an E. coli factory. We also scheduled an online meeting for August 11 to refine the book's framework, assign tasks, and advance the collaboration.

The core takeaway from this exchange was clarifying project optimization pathways through multiple team presentations: - iZJU-China's “DNA Origami Encapsulation Technology” provided insights for magnetic enzyme upgrades—we plan to add a biocompatible coating to enhance enzyme tolerance in complex waste environments while eliminating leakage risks; The TJUSX team's “Dual Temperature/pH-Sensitive Suicide Gene” approach supplemented our engineered bacteria's safety design redundancy. Building upon the existing temperature-sensitive mechanism, it incorporates an pH-abnormality-triggered self-destruct program to reinforce ecological safety. The Nanjing University team's “MOA Visualization for Science Communication” concept provided direction for optimizing the Wiki's biosafety section. Additionally, the Peking University team's “simplified logic for targeted delivery” inspired us to design equipment operation as a “one-button start” mode, adapting to non-professional operational scenarios like communities and tourist attractions.

During the iGEM cross-track exchange, this meeting's “technical mutual learning and complementary strengths” model helped us accumulate project optimization ideas and establish collaboration leads with the Jilin University team. These efforts are precisely the driving force propelling synthetic biology toward solving real-world problems.

2.2 Jilin University Collaborative Exchange Meeting

To foster cross-institutional exchange and collaboration among iGEM teams, share valuable practical experience, and explore leveraging mutual strengths to enhance project social impact, the iGEM teams from the University of Electronic Science and Technology of China (UESTC-China) and Jilin University held an online exchange meeting on August 11. This meeting aimed to facilitate mutual learning, inspire new ideas, and ultimately materialize a concrete collaborative outcome.

The University of Electronic Science and Technology of China (UESTC-China) project focuses on tackling plastic pollution through synthetic biology. By developing a “magnetically immobilized dual-enzyme” system and metabolic engineering strains, the project degrades waste PET plastic and upcycles it into high-value chemicals (such as polyamide esters and protocatechuic acid), striving to achieve “green degradation and resource recovery” of plastics. The Jilin University (JLU-CP) project focuses on space health, aiming to design an engineered probiotic strain dubbed the “Space Sleep-Promoting Bacteria.” This strain biosynthesizes melatonin, with its production precisely regulated through innovative temperature- and sound-controlled systems. This addresses sleep disorders in astronauts caused by circadian rhythm disruption in space environments.

During the meeting, members from both teams provided detailed updates on their respective projects' human practice progress, activities, and science communication strategies.

Despite their divergent research directions—one focused on “environmental challenges on Earth,” the other on “health issues in space”—both teams recognized that synthetic biology's appeal lies in its ability to creatively solve problems across different fields through an engineering approach. This “unity in diversity” presents a unique opportunity for collaboration.

The meeting served not only as a successful exchange of experiences but also as an innovative collaborative practice. Both parties agreed to maintain close communication to advance the production and release of the picture book project. We believe this cross-team, cross-disciplinary collaboration will yield synergistic results, collectively contributing to enhancing public scientific literacy and showcasing the boundless potential of synthetic biology.

2.3 Project Content and Expert Recommendations

1. Report on Bioinformatics Interview with Professor Fuying Dao of Nanyang Technological University

To advance research on the high-value microbial conversion of ethylene glycol (EG), a byproduct of PET depolymerization, the Human Practice and Bioinformatics Group of the iGEM team at University of Electronic Science and Technology of China recently conducted an email interview with Professor Fuying Dao, Schmidt AI Fellow at the Faculty of Biological Sciences (FBS), Nanyang Technological University. The discussion focused on challenges related to “bioinformatics modeling and enzyme function prediction” encountered in the project. Professor Dao acknowledged the team's research approach and provided expert, in-depth guidance on four key issues:

(1) Analysis of glxR and garR Substrate Specificity

Professor Dao endorsed our proposed strategy combining AlphaFold2 homology modeling, active site alignment, and molecular docking/short-range MD simulations. She recommended integrating conserved residue analysis and mutation experiment data to enhance the reliability of substrate binding preference predictions.

(2) Dynamic modeling approach for GEM

Addressing the limitation of traditional metabolic models in responding to dynamic perturbations, the professor suggested integrating time-series transcriptomic and metabolomic data. He recommended parameter optimization using dynamic flux balance analysis (dFBA) or ODE-based coupled models, with potential integration of machine learning methods in subsequent stages to improve predictive performance.

(3) Modeling Strategies for Enzyme Activity Dynamics

Professor Dao highlighted that enzyme-constrained metabolic models (ecGEM) can incorporate enzyme parameters like kcat and Km. When experimental data is limited, databases such as BRENDA and omics data can be leveraged to infer parameters, thereby more accurately reflecting the impact of enzyme activity changes on metabolic flux.

(4) Algorithmic Cross-fertilization Between Computational Metabolic Engineering and Drug Design

Both disciplines follow a “design-test-learn” cycle. Metabolic engineering can adopt molecular dynamics refinement validation commonly used in drug design, while drug design can incorporate system-constrained optimization approaches from metabolic engineering. Reinforcement learning, evolutionary algorithms, and interpretable models represent key shared tools.

Professor Dao's feedback provided the team with clear technical pathways and practical recommendations for enzyme function prediction, dynamic modeling, enzyme constraint optimization, and cross-domain algorithm integration, offering highly insightful guidance. The team will progressively implement these suggestions in subsequent research to further enhance the project's scientific depth and engineering feasibility.

For detailed content, please refer to Attachment 5.

2. Interview Report with Professor Li Tao from Guang'anmen Hospital, China Academy of Chinese Medical Sciences

To overcome bottlenecks in engineered microorganism construction and product validation, the iGEM team from University of Electronic Science and Technology of China recently sought professional guidance from Professor Li Tao at Guang'anmen Hospital, China Academy of Chinese Medical Sciences. After carefully reviewing the project materials, Professor Li Tao endorsed the team's overall approach to maximizing PET degradation product value. He provided highly constructive key guidance and important reminders addressing current core challenges.

(1) Overall Feedback on “Product Extraction Failure” and “Pathway Optimization Challenges”

Professor Li Tao explicitly stated that the primary issue in the current project is not the purification process, but whether the metabolic pathway itself has been successfully established. He expressed reservations about the engineered bacteria's ability to synthesize polyethyleneamides (PEAs) from EG, emphasizing that optimizing extraction methods holds little value before confirming successful product synthesis. Given limited time and resources, the professor recommended prioritizing microbial utilization of ethylene glycol (EG) over terephthalic acid (TPA) conversion. He noted that while TPA conversion has seen substantial high-level research in recent years, achieving breakthroughs remains challenging. Focusing on EG could better establish a clear and competitive project narrative.

(2) Regarding metabolic pathway construction: The professor expressed “surprise” at the undetected products, pinpointing the core issue as the “zero-to-one” validation. He recommended a stepwise troubleshooting approach: First, confirm normal expression of introduced genes (gcl, hyi, etc.). Second, verify successful synthesis of key intermediates along the metabolic pathway. Address optimization challenges like cofactor balance and pathway competition only after resolving these foundational issues.

(3) Regarding product detection methods: Given challenges in polymer extraction and quantification, the professor recommended prioritizing the development of precise detection methods for monomers or intermediates, such as using high-performance liquid chromatography (HPLC), to obtain more reliable data.

(4) Regarding strain and induction optimization: The professor views induction condition refinement and gene knockout as “1 to 100” precision operations. At the current “0 to 1” stage, the team should focus on identifying the root cause of pathway failure rather than prematurely delving into detailed optimizations. He also emphasized the fundamental prerequisite of verifying whether the engineered strain can survive using EG as the sole carbon source.

Professor Li Tao's guidance was incisive, redirecting the team's attention from secondary issues to core challenges. His core recommendation centered on: the current priority should be fundamentally validating the metabolic pathway's feasibility through a rigorous step-by-step troubleshooting strategy, prioritizing reliable detection methods to obtain critical data. The team will immediately adjust the research plan, first focusing on verifying gene expression and intermediate synthesis to solidify the project foundation.

For specific details, please refer to Attachment 6

2.4 Field Research at Maike High-Tech Materials

To gain deeper insights into the practical application of biodegradable materials in industrial production and learn from leading companies' commercialization experiences, our iGEM team recently conducted field research at Maike High-Tech Materials. This included an in-depth interview with the company's technical lead, Zhang Li, and an on-site tour of their agricultural film production facility. The aim was to bridge laboratory research with industrial practice, thereby optimizing our PET biodegradation and high-value conversion project plan.

During discussions with Mr. Zhang Li, we engaged in in-depth exchanges on critical issues including technical bottlenecks, market promotion, biosafety, and policy drivers for biodegradable materials. Key takeaways are as follows:

(1) Clarifying Industrialization Pathways

Maike Gaocai emphasized that a complete process from “small-scale trials → pilot-scale trials → large-scale production” is crucial for technology commercialization. They advised us to proactively collect multi-batch stability data during the laboratory phase, focusing on equipment compatibility, parameter control, and quality consistency.

(2) Cost Control Requires a Full-Chain Perspective

The company pointed out that end-users often evaluate costs from a single perspective. They recommended optimizing our cost structure through aspects like raw material selection (e.g., industrial-grade substrates) and conversion efficiency improvements, while incorporating a full-industry-chain cost assessment mindset into our projects.

(3) Biosafety is a red line

Especially when involving engineered strains and novel materials, biosafety must be integrated into the assessment system from the early R&D stages. Public acceptance should be advanced through dual tracks: authoritative testing and accessible science communication.

(4) Market promotion strategies must be pragmatic

“Authoritative certification + accessible science communication” is the core strategy for successfully promoting mulch film products. We plan to incorporate collaboration with testing institutions into the project and visually demonstrate technological safety through formats like short videos.

(5) Significant Variation in Customer Needs

Large enterprises prioritize technological reserves, while SMEs focus more on cost. Project presentations must therefore highlight corresponding advantages—such as technological originality or economic potential—tailored to different audiences.

During the field visit to the mulch film production facility, we observed:

High automation throughout the production line, with fully enclosed management from raw material input to finished film rolls, demonstrating strict control over quality consistency and production environmental standards; The company prioritizes energy consumption and waste management during production, aligning with its “green technology” philosophy.

This research not only deepened our understanding of the biodegradable materials industry but also provided clear direction and methodologies for advancing the iGEM project from laboratory to industrialization. We extend our gratitude to Maike Gaocai for their professional insights and support, and look forward to further exploring possibilities in technology transfer and industry-academia-research collaboration.

For the full interview report, please refer to Attachment 7.

(IV) Reflections and Growth: Knowledge Gained Through Experience Holds the Greatest Power

We have traveled a long road.

From the sterile benches of the laboratory to the unloading port of a fifth-level underground waste compaction center; from computers running metabolic pathway models to the churning brown water of a landfill leachate nitrification tank; from envisioning perfect degradation curves to the real-time data screens pulsing in the incineration plant's control room.

This journey taught us to stop asking “Is this technology advanced?” and instead ask “Does the world need this?” It instilled in us the “power to ground ourselves in reality.” Book knowledge is flat, but the soil saturated with microplastics at landfills, the mixed waste in compactor machinery, and the mineral water bottles in protected forests made abstract data and technical challenges tangible and urgent. Never before have we grasped so profoundly why our project exists and for whom it serves.

It instilled in us the “power to dare to reconstruct.” We fearlessly overturned our own assumptions. Many initial concepts underwent continuous refinement, optimization, and even complete reshaping under the scrutiny of reality. We realized that true innovation requires the courage to iterate ideas based on real-world feedback.

It has instilled in us the “power of unity and collaboration.” From lab partners to field research teammates, and through our collaboration with the Jilin University team, we deeply grasped that tackling a monumental issue like plastic pollution requires openness, cooperation, and co-creation to harness the immense energy for change.

Human practice has reached a pause, but we firmly believe the story of plastic should not end in pollution. Thus, carrying the insights and sense of responsibility gained from the Chinese landscape, we return to the lab to dedicate ourselves fully to the final sprint of the iGEM project:

We will strive to create a more resilient, pragmatic, and needs-oriented solution;

We will continue to spread rational, optimistic, and responsible scientific voices;

We aspire for our work to not only earn the judges' recognition but also contribute the wisdom, sincerity, and commitment of China's youth to advancing the circular economy for plastics—both in China and around the world.

Appendix

Appendix 1:

Research and Recommendations Report on Implementing the “14th Five-Year Plan” Action Plan for Plastic Pollution Control and Innovating PET Plastic Pollution Management Models

Submitted by: iGEM Team, University of Electronic Science and Technology of China

Date: September 2025

I. Introduction and Background

To thoroughly implement the “Action Plan for Plastic Pollution Control during the 14th Five-Year Plan Period” jointly issued by the National Development and Reform Commission and the Ministry of Ecology and Environment (hereinafter referred to as the “Plan”), and to advance the transformation of plastic waste into valuable resources and promote circular utilization, the iGEM Team of the University of Electronic Science and Technology of China, leveraging its technical expertise in synthetic biology (having won the Gold Medal at the International Genetically Engineered Machine Competition for 12 consecutive years and holding relevant national invention patents), conducted an in-depth investigation spanning several months. This research focused on addressing pollution control and high-value recycling of PET (polyethylene terephthalate) plastics.

The team visited frontline plastic pollution management units including the Sangzhi Badagongshan National Nature Reserve, Sangzhi County Environmental Sanitation Bureau, and Everbright Environmental Energy (Zhangjiajie) Co., Ltd., while also engaging with leading eco-material enterprises like Maike Gaocai. This aimed to identify current pain points in PET management and validate the application potential of a novel “biorecycling” pathway centered on synthetic biology technology. This report synthesizes research findings and, aligned with the guiding principles of the Action Plan, provides data-driven insights and policy recommendations to innovate plastic pollution management models.

II. Current Status and Challenges: Core Obstacles in PET Plastic Management

Our investigation identified three fundamental contradictions within the existing PET management system, which closely align with the systemic issues the Action Plan seeks to address:

1. The Conflict Between “Reduction” and “Growth”: Difficulties in source reduction and massive existing pollution stockpiles.

In the Ba Da Gong Shan Nature Reserve, plastic waste accounts for over 70% of litter, primarily originating from domestic and tourism activities. This poses direct threats to soil, water bodies, and wildlife (e.g., fatal ingestion cases). This underscores the necessity and urgency of the Plan's initiative to “clean up and remediate plastic waste in key areas.” Simultaneously, historical plastic waste in rural Sangzhi County (e.g., agricultural films, discarded bottles) resists natural degradation, creating persistent “white pollution” stockpiles.

2. The conflict between “recycling” and “downcycling”: Inadequate recycling systems result in low resource recovery rates and diminished value.

Currently, grassroots levels generally lack specialized PET sorting processes, relying instead on a “mixed collection, mixed processing” model. Recycling predominantly depends on scattered scrap stations performing basic physical regeneration (melting and pelletizing), resulting in products facing the dilemma of “downcycling” with low economic value. The county sanitation department reports that household waste treatment costs reach approximately 200 yuan per ton, imposing a heavy fiscal burden, while the resource value of plastics remains largely untapped.

3. The Conflict Between “Disposal” and “Secondary Pollution”: End-of-pipe disposal methods are limited, posing environmental risks and resource wastage.

Landfilling: Occupies land resources; PET takes decades to degrade, and microplastics in leachate remain inadequately assessed and treated. Incineration: While achieving volume reduction and power generation (e.g., Everbright Environmental employs advanced technology to ensure emission compliance), PET's chlorinated additives may increase HCl emission risks. Moreover, its high-value potential is entirely lost during incineration—essentially treating “resources” as ‘waste’ and failing to realize the “high-value utilization” advocated by the Plan.

III. Innovation and Exploration: Synthetic Biology Technology Offers a New “Biocircular” Solution

Addressing these challenges, our team's developed “Magnetic Enzyme-Engineered Bacterial System for PET Biodegradation and High-Value Conversion” provides a novel technical pathway for “promoting resource utilization of plastic waste” as outlined in the Plan:

1. Core Technology: A two-step “enzyme-bacteria coupling” approach.

2. Efficient Degradation: Utilizes magnetically co-immobilized PET hydrolases to rapidly depolymerize PET into monomers TPA and EG under mild conditions. The magnetic carrier enables rapid enzyme recovery and reuse, significantly reducing operational costs.

3. High-Value Conversion: Metabolic engineering of E. coli constructs novel pathways to convert inhibitory degradation products (TPA and EG) into high-value outputs like polyester amides (PEAs, biodegradable plastic feedstock) and protocatechuic acid (pharmaceutical/flavor intermediate) in real time.

4. Innovative Value: This approach achieves a leap from “degradation” to “upcycling,” addressing the urgent demand for “high-value utilization” outlined in the Plan. Simultaneously, magnetic enzyme immobilization technology resolves industry challenges of high enzyme costs and poor stability. Instantaneous product conversion overcomes the critical bottleneck of EG/TPA accumulation inhibiting degradation efficiency, thereby achieving a true closed-loop biocycle: “Waste PET → Monomer TPA and Monomer EG → High-Value Products.” This addresses shortcomings in existing physical and chemical recycling methods.

IV. Research Findings: Implementation Potential and Practical Constraints

Multiple surveys indicate this technology holds widely recognized application potential but faces common challenges in scaling from lab to industry:

1. Broad Demand: From nature reserves (seeking reduced waste removal costs) and county sanitation bureaus (expecting waste “value-add” to ease fiscal pressure) to incineration plants (acknowledging its potential as front-end pre-treatment), all express strong interest.

2. Core Concerns (Feedback from Industry Frontlines):

(1) Economic viability is paramount: The full-process cost must be demonstrated to be lower than or comparable to existing methods (200 RMB/ton).

(2) Stability is essential: Enzymes and microbial strains must maintain high efficiency and stability in complex, non-sterile real-world waste environments.

(3) Safety is non-negotiable: Comprehensive biosafety and environmental risk assessments must be certified by authoritative bodies (e.g., CNAS).

(4) Interoperability is key: The technology must integrate into existing waste collection, transportation, and disposal systems—e.g., combining with AI sorting systems to process PET-enriched fractions.

(5) Market viability is assurance: The resulting PEAs and protocatechuic acid must obtain corresponding market access and quality certifications to establish sales channels.

V. Policy Recommendations

Based on the guidance of the Plan and insights from this research, we propose the following recommendations:

1. Strengthen technological innovation and industrial integration, supporting demonstration projects for “biorecycling” technologies.

Recommend that science and technology, environmental protection departments establish dedicated programs to prioritize support for innovative directions outlined in the Plan, such as bioenzyme-catalyzed degradation. Encourage pilot projects for PET biorecycling based on this technology in “Zero Waste City” construction areas like Zhangjiajie, providing site, raw material (sorted PET waste), and policy support to validate its engineering feasibility.

2. Improve the recycling system to provide “high-quality feedstock” for high-value utilization.

Strictly implement the Plan's requirement to “accelerate standardized recycling and utilization of plastic waste.” Expedite the construction of waste sorting facilities in areas like Sangzhi County and promote technologies such as AI optical sorting to enhance the purity and efficiency of PET waste collection. This will ensure a stable and qualified feedstock supply for biotechnological processes.

3. Establish a green certification and procurement system to open market channels for high-value products.

Recommend that market regulators develop certification standards for bio-based recycled materials (e.g., PEAs), incorporate them into the National Recycled Materials Catalog and government green procurement lists, and create market pathways for green products generated by innovative technologies. This will foster a virtuous cycle of “processing → high-value products → market returns.”

4. Strengthen science communication and public engagement through an “authoritative certification + accessible science outreach” model.

Building on the success of Maike Gaocai, technology promotion should leverage authoritative testing data to demonstrate safety and efficacy while using accessible formats like short videos and lab open houses to visually convey the value story of “plastic bottles becoming perfume.” This approach reduces NIMBYism and enhances societal acceptance.

VI. Conclusion

Addressing PET plastic pollution is a systemic endeavor. Our team's technological exploration indicates that synthetic biology holds promise to provide critical technical reinforcement and high-value solutions for the comprehensive governance framework outlined in the “14th Five-Year Plan Action Plan for Plastic Pollution Control.” However, successful implementation relies not only on sustained laboratory innovation but also on robust policy guidance, improved recycling systems, and collaborative efforts across the industry.

We firmly believe that through the deep integration of policy, technology, and market forces, and by promoting innovative models like the “biocircular economy,” we can accelerate the realization of “green degradation and resource recovery” for plastic pollution. This will make substantial contributions to China's ecological civilization development and the goal of building “waste-free cities.”

Appendix 2:

Following our landfill observations, we conducted an in-depth interview with Director Xiang Yong of the Environmental Sanitation Bureau. Director Xiang candidly shared practical bottlenecks at the grassroots level, helping us further identify specific pain points and needs in plastic waste management within county-level scenarios. Below are five key Q&A segments selected from the interview:

Q1: Regarding current disposal methods (landfill/incineration) for plastic waste, what specific issues have you observed? For example, processing costs, secondary pollution, or resource waste? What is the most prominent plastic waste management issue in your work? (e.g., low recycling rates due to mixed waste, high transportation costs, insufficient end-disposal capacity)

A: Landfilling requires stringent groundwater protection and leachate treatment, but current leachate management focuses solely on ammonia nitrogen reduction without addressing microplastics. Plastics are difficult to degrade—plastic buried decades ago remains intact when excavated. Regarding incineration, plastic has low calorific value and requires exhaust gas treatment. Factoring in labor, transportation, and end-of-life processing fees, the cost per ton of waste disposal is approximately 200 yuan. Our county sanitation bureau spends over ten million yuan annually on waste processing. We would eagerly explore certified plastic upgrading technologies—after all, waste is a resource in the wrong place. Direct incineration or co-processing fails to unlock its value. Efficient resource utilization saves money and promotes sustainability. The real headache is the scattered and complex nature of plastic pollution: rural areas are vast, with plastics strewn across fields and riverbanks, making collection and transportation costly. Beyond PET bottles, there are packaging films, agricultural films, and other materials with mixed compositions. This poses a challenge for your biotechnology—can enzymes and engineered bacteria process mixed plastics? Is pre-sorting necessary? These factors must be considered.

Q2: Based on your management experience, what direction should future plastic waste treatment (especially PET) take? Should the emphasis be more on “recycling and reuse” rather than “final disposal”? What conditions would you prioritize for future technologies? For example, should they directly degrade plastics and produce high-value products?

A: “Recycling and reuse” must definitely be prioritized; “final disposal” is a last resort. Future technologies should first address reality—waste is complex, not pure PET from a lab. Your biotechnology must remain stable and efficient in this environment.

Economic viability is also crucial. At minimum, professional institutions must validate that new technologies prove cost-effective over the long term compared to existing methods. While direct degradation into high-value products is ideal, we should first tackle the “complex composition impacting efficiency and purity” caused by inadequate sorting. This will drive technology toward more specific, stable, and efficient iterations. Building on existing technological strengths first also lays the groundwork for advanced research later.

Q3: Based on your management experience, can such “turning waste into treasure” technologies address specific pain points in current PET processing?

Answer: Your “magnetically immobilized dual-enzyme” concept is excellent—magnetic enzyme recovery could indeed reduce costs. However, several practical considerations exist: First, can enzyme activity be maintained in actual waste environments? Impurities, substrate temperatures, and pH fluctuations may impact performance. We recommend prioritizing enzyme stability and developing simple detection methods to help operators monitor reaction progress. Second, product marketability: Are there buyers for PEA and protocatechuic acid from a county-level facility, and what are the purchase volumes? Additionally, consider the “feed” costs for engineered bacteria—our leachate treatment requires glucose supplementation, which must be factored into expenses. Providing effective technology or equipment alone is insufficient; stakeholders need comprehensive solutions to alleviate concerns and reduce implementation barriers.

Q4: From a technological reserve perspective, what role/value do you see our biodegradable plastic technology playing in the current plastic pollution management ecosystem? Does it fill a technological gap or address a technical shortcoming?

Answer: Your technology both fills a gap and addresses a shortcoming—currently, no mature technology efficiently converts PET into high-value chemicals, which fills the gap; existing plastic treatment methods waste resources, which addresses the shortcoming. What I value most is the paradigm shift your technology enables—treating “waste” as a temporary transitional state of resources, not their final destination. This helps elevate our sanitation work beyond mere hygiene to genuine environmental protection.

However, note that laboratory technologies often underestimate the challenges of industrial integration. No matter how advanced the technology, it must integrate into existing waste processing chains. We recommend starting with scenarios like tourist attractions and commercial districts where PET volumes are high and composition is simple—this approach increases the likelihood of success.

Q5: What challenges do you foresee in promoting this “biodegradation + resource recovery” technology? (e.g., cost, operational complexity, integration with traditional systems) How should we adapt it to better meet grassroots needs? What advice do you have for public outreach on PET recycling and environmental education?

A: Challenges are inevitable during rollout. First is cost—initial investment in new technology is inevitably high. Second is operational complexity, as grassroots personnel may lack biotech expertise. Most critical is integration with existing systems—how to embed your technology as a seamless link within current frameworks.

Your project appears preliminary. While it validates the technical feasibility of this approach, it hasn't demonstrated practical implementation potential. Key questions remain: Is it currently only suitable for lab-scale operation? How does it compete with existing methods? Technical stability and economic viability are paramount.

When communicating with the public, I suggest highlighting tangible benefits like how much the recycling price per pound of plastic bottles increases after plastic recycling plants adopt this technology. Also, clearly explain the specific harms of plastic pollution and the necessity of waste sorting—these points are more relatable to daily life. Additionally, pay attention to the angle of your messaging. Combine it with environmental education to empower people, letting them know that their small actions can determine the fate of waste and even benefit them.

Appendix 3:

Regarding PET plastic processing, we conducted multiple rounds of follow-up inquiries with the manager of Yixun. Six key Q&A sets have been selected from the interviews, highlighting both genuine pain points from the industrial frontlines and practical challenges the project must address:

Q1: Does the combustion behavior of PET plastic have any special impact on incineration processes and emission controls?

A: PET is typically incinerated in the form of plastic bundles (e.g., mixed film bags containing PET+PVC). However, since PVC contains chlorinated additives that may increase HCl emissions, enhanced acid removal processes are required to control HCl emissions. PET itself is generally chlorine-free, and co-incineration with PVC represents more of a “resource waste.” Rough estimates indicate PET constitutes about 5%-8% of incoming waste. While its medium-high calorific value of 23 MJ/kg helps maintain furnace temperatures, partial diversion of PET before incineration could prevent its high-value potential from being squandered “merely as fuel.”

Q2: Are there significant shortcomings or technological upgrade needs in current PET processing methods?

Answer: Systemic shortcomings do exist, primarily manifesting in three dimensions:

1. Technical bottlenecks: Physical recycling faces a “degradation cycle” dilemma (after 3-5 cycles, IV values drop from 0.8-0.9 to 0.4-0.5, limiting applications to low-end products); chemical recycling (alcoholysis, saccharification) suffers from high energy consumption and difficulty in ensuring purity.

2. Systemic issues: Inefficient sorting and barriers to recycled material adoption.

3. Urgent technological upgrade needs: 1. Intelligent PET sorting technology; 2. Low-carbon depolymerization processes (developing bioenzymatic or low-temperature catalytic depolymerization); 3. High-value conversion pathways — precisely the type of technology your team is researching: converting EG into PEAs (polyester amides) and TPA into protocatechuic acid.

Q3: Do you believe our technology possesses the same grassroots, large-scale application potential as the biological denitrification processes currently used in landfill leachate treatment?

Answer: It has potential, but faces more complex challenges:

Substrate complexity: Leachate composition is relatively stable, whereas PET sources in municipal solid waste are diverse (bottle flakes, films, fibers, etc.). The inhibitory effects of additives, pigments, and residual contents on enzymes and microorganisms require systematic evaluation.

Economic Barriers: Leachate treatment benefits from stringent environmental mandates and high cost tolerance (treatment fees reach 50-100 RMB/ton), whereas plastic recycling faces direct competition from virgin materials and extreme cost sensitivity.

Product Marketability: Leachate treatment produces compliant water and sludge with clear outlets; your approach requires establishing sales channels and quality certification systems for PEA and protocatechuic acid—a significantly greater challenge.

Q4: Based on industrial experience, what key issues must be resolved for this technology to be practically implemented? What real-world barriers might hinder its adoption?

Answer: 1. Enzyme cost and stability require special attention: Enzyme costs must be minimized (via magnetic immobilization, high-yield strains, etc.), while maintaining high and stable activity under non-sterile conditions.

2. Process intensification and integration: Engineering challenges including rate matching between degradation and conversion modules, mass transfer, and energy integration must be addressed to ensure seamless, continuous, and efficient operation of the biodegradation conversion system while minimizing product accumulation between stages.

3. Product certification and market access: As novel bio-based biodegradable plastics, PEAs require relevant certifications for market entry; protocatechuic acid, as a pharmaceutical intermediate, must meet specific industry standards; bio-based recycled plastics are currently excluded from the National Catalog of Recycled Raw Materials, potentially complicating product identity recognition.

Q5: From which perspectives should we communicate this “plastic transformation” narrative to governments, businesses, and the public?

Answer: For the government: 1. Directly align with the “Chemical Recycling/Bio-Enzyme Catalysis” breakthrough direction specified in Column 2 of the “14th Five-Year Plan Action Plan for Plastic Pollution Control.” Clause 4.3.2 of the “Technical Specifications for Waste Plastic Pollution Control” (HJ 364-2022) lists “enzyme catalysis, alcoholysis, and glycolysis” as encouraged technologies.

Highlight the “closed-loop recycling” characteristic: PET → Enzymatic hydrolysis → TPA/EG → Bioconversion → PEAs (degradable plastics)/Protocatechuic acid (pharmaceutical intermediate). This aligns with the “same-level recycling and high-value utilization” principle outlined in the National Development and Reform Commission's “Strategy for Refined Recycling of Plastic Waste.”

For enterprises: Promote product specificity—biologically derived PEAs offer controllable degradation rates and mechanical properties, making them suitable for high-end agricultural films, medical devices, etc. This highlights the “lifecycle cost advantages” and “functional premium” of downstream processed products. Alternatively, emphasize the cost competitiveness of your outputs.

For the public: Communicate value through visual, tangible means. Develop compelling, counterintuitive messaging points your team deems engaging—such as " e.g., “Plastic Bottles Turned into Perfume.” However, genuinely understand public perceptions of biotechnology—avoid relying on subjective assumptions. For instance, many people equate ‘biodegradable’ with “slow + expensive.” Address these stereotypes by challenging common misconceptions or designing public experiences: clearly demonstrate how long it takes for a mineral water bottle to degrade naturally vs. through bio-degradation, and showcase the value of the resulting products.

Q6: What advice do you have for young research teams? How should they balance laboratory technical idealism with applied pragmatism?

Answer: 1. Start with the end in mind: Reverse-engineer development. Don't begin with “what technologies we have,” but instead work backward from “what products the market needs.” Identify stakeholders' core demands for recycled materials.

2. Build a community of shared interests: Implementing new technology isn't just about replacing existing methods—it's about restructuring industrial value chains. Consider how waste sorting plants can profit by supplying raw materials, chemical factories can reduce costs by sharing infrastructure, and product users can enhance brand image by adopting green materials. Only when every link benefits can the technology truly take root.

3. Master “cost control”: Don't chase “perfect technology”; pursue “cost-effective solutions.” Incinerator mechanical grapples aren't “state-of-the-art,” but they're “adequate, durable, and low-maintenance.” Waste heat utilization isn't “the most complex process,” but it's “proximity-based and low-cost.” This serves as a reminder: When implementing PET projects, avoid obsessing over “laboratory-level peak efficiency.” Instead, focus on developing “affordable technology for grassroots use.”

Appendix 4:

1. Waste Composition: 70% Plastic Content, Concentrated Sources Yet Dispersed Distribution: With no industrial production in the reserve, waste primarily originates from local residents, scientific expeditions, and tourists. However, plastic accounts for over 70% of the waste—far exceeding the PET proportion in urban household waste. Common types include PET bottles and plastic bags mixed with aluminum cans and discarded equipment. Despite seemingly concentrated sources, the reserve's vast area and dispersed human activity result in “scattered points and dispersed areas” of waste distribution—a stark contrast to urban waste's “centralized collection and transportation” model.

2. The ecological hazards of plastic waste are more direct and lethal here:

Environmental level: Degraded plastic leaches into soil and water bodies, disrupting microbial communities. As one of Nongfu Spring's 15 major water sources, the Ba Da Gong Mountains directly impact downstream water safety and public health.

At the animal level: Director Gu mentioned that “wild animals have been found dead from plastic bag ingestion causing digestive tract blockages,” and plastic residues are frequently detected in other animal carcasses. This underscores that in ecological zones, plastic management is not merely “resource recycling” but “life preservation.”

The urban model of “centralized compression - transportation - incineration/landfill” is entirely impractical in Badagongshan. Director Gu highlighted three major challenges:

1. Collection Difficulty: Despite designated collection points and dedicated collection vehicles, some waste is still discarded indiscriminately in forests and waterways. Staff must hike into remote areas to collect this litter, with some sections posing landslide risks. “The collection cost far exceeds the value of processing the waste itself.”

2. High Costs: The entire process—collection, transportation, and delivery to urban treatment facilities—incurs multiple costs for personnel, vehicles, and equipment, placing significant financial pressure on the ecological reserve. “Long-term maintenance is extremely difficult”—this directly contradicts the urban treatment logic of “economies of scale reducing costs.” It also highlights that ecological zones require not “large-scale, comprehensive” treatment plants, but “small-scale, flexible” localized solutions.

3. Zero-pollution requirement: The ecological sensitivity of protected areas dictates that no treatment technology may generate new pollution (e.g., catalyst residues from chemical methods, flue gas emissions from incineration). This aligns perfectly with the strengths of our PET biodegradation technology: “operating at ambient temperature and pressure with no secondary pollution.”

Director Gu emphasized core requirements: “high-efficiency, low-cost products; streamlined processes; environmental harmlessness; and reduced collection/transportation investment.” We envision encapsulating our “magnetically anchored dual-enzyme + engineered bacteria” technology into replaceable “bioreactor cartridges” or “bio-filter cores” for installation at small waste collection points within protected areas. Staff would only need to periodically replace the cartridges (no specialized operation required) to achieve on-site degradation of PET plastics. Performance optimization should also focus on “low cost + low residue,” avoiding long-distance transportation costs and ecological risks.

Director Gu also advised that “promotion should be relatable and down-to-earth,” shifting science outreach from “urban lectures” to “ecological empathy.” Based on this, we adjusted our environmental science communication approach: Rather than abstractly discussing “plastic hazards,” we will design content integrating case studies from protected areas or other representative scenarios.

Attachment 5: Professor Dao's Reply

Dear iGEM Team at University of Electronic Science and Technology of China:

Greetings! We are delighted to receive your letter and learn about your research exploring high-value conversion of ethylene glycol (EG), a byproduct of PET depolymerization. Your research approach is well-structured, and the integration of comparative genomics with metabolic modeling shows great promise. Regarding your questions, here are some personal insights for your reference:

(1) Substrate Specificity of glxR vs. garR

Using homology modeling/AlphaFold2 to obtain 3D structural models, combined with pocket prediction tools (e.g., SiteMap, FPocket), molecular docking, and short-range molecular dynamics simulations, is a reasonable approach. Note that binding energy differences may be subtle. Beyond docking analysis, we recommend integrating conserved residue analysis and binding site mutation data to enhance the reliability of substrate specificity predictions.

(2) Improving Non-Dynamic GEMs

To address GEM's steady-state assumption, consider integrating time-series transcriptomics and dynamic metabolomics data for dynamic parameter calibration. Several approaches have been explored, including dynamic FBA (dFBA), ODE-based model coupling, and recent machine learning-driven parameter estimation methods. Practical implementation hinges on ensuring sufficiently dense temporal sampling across multi-omics datasets and balancing interpretability with predictive performance in algorithm selection—e.g., starting with traditional dFBA frameworks before exploring deep learning-based dynamic modeling.

(3) Modeling dynamic changes in key enzyme activity A common current approach involves constructing enzyme-constrained GEMs (ecGEMs) by incorporating enzyme parameters like kcat and Km. Such models partially reflect how enzyme activity variations influence flux allocation. When complete enzyme parameters are unavailable, omics-based inference (transcriptome/proteome quantification) combined with databases (e.g., BRENDA) can approximate parameter values, thereby enhancing the model's accuracy in predicting product synthesis efficiency.

(4) Insights from Computational Metabolic Engineering and Computer-Aided Drug Design Both disciplines share the core “design-test-learn” cycle. In metabolic engineering, the emphasis lies in the global optimization of multi-gene, multi-enzyme systems; whereas drug design focuses more on the precise interaction mechanisms between single molecules and targets. Key algorithmic insights shared between the two fields include: utilizing evolutionary algorithms or reinforcement learning to optimize design spaces; prioritizing the introduction of “interpretable models” between prediction and validation; and emphasizing iteration speed and feedback utilization efficiency. These insights are fully transferable across domains. For instance, metabolic engineering could adopt the molecular dynamics refinement validation steps common in drug design, while drug design could borrow metabolic engineering's systematic constraint optimization approach.

Finally, thank you for your trust and invitation. We wish your project every success and look forward to your outstanding achievements in the iGEM competition!

Best regards,

Fuying Dao

Schmidt AI in Science Fellow, School of Biological Sciences (SBS), Nanyang Technological University

Attachment 6:

Dear Professor Li Tao,

Greetings!

We are a student team from the University of Electronic Science and Technology of China participating in the 2025 International Genetically Engineered Machine Competition (iGEM). Upon recommendation by Professor Deng Kejun from our School of Life Sciences and Technology, we learned of your profound expertise in the relevant field. We respectfully request your guidance for our project.

Our current project aims to construct a biodegradation and upcycling system for PET plastic. Its core involves depolymerizing PET using magnetically immobilized PET hydrolase and designing two independent microbial metabolic pathways. These pathways respectively convert the depolymerization products ethylene glycol (EG) and terephthalic acid (TPA) into high-value polyethyleneamides (PEAs) and protocatechuic acid (PCA).

During project advancement, we have encountered specific technical challenges and earnestly request your guidance and valuable suggestions. Attached is a detailed PowerPoint presentation of our project for your reference.

I. Project Background and Challenges

We degrade PET into ethylene glycol (EG) and TPA through the multienzyme magnetic co-immobilization of PETase and MHETase, enabling transient synergistic hydrolysis. We primarily engineered Escherichia coli BL21(DE3) (introducing gcl, hyi, glxR, glxK, etc.) to synthesize polyester amides (PEAs) using EG as a carbon source. However, we currently face two major challenges:

1. Product extraction failure: Although the metabolic pathway has been constructed, the engineered bacteria failed to yield PEA products in EG medium. Our current PEA extraction method is as follows: Take 300 mg of bacterial cells, centrifuge and freeze-dry them. Incubate the freeze-dried cells with chloroform at 35°C for 24 hours. the chloroform extract is filtered through a 0.2μm pore size PTFE membrane filter, chloroform is evaporated and concentrated under airflow in a fume hood, and finally 10 volumes of methanol are added, followed by centrifugation for collection.

Response: Thank you very much. After reviewing your presentation, I remain uncertain whether your engineered strain can effectively utilize EG to synthesize PEAs. This appears to be a lengthy pathway, and I have not seen specific engineering schematics or experimental data. Therefore, I maintain reservations about your strain's PEAs synthesis capability. Additionally, the Nile Red staining detection method lacks high accuracy. Therefore, I recommend first thoroughly confirming that your bacteria can indeed convert EG into PEAs. Otherwise, pursuing purification efforts would be futile. Second, assuming successful PEAs synthesis, I suggest referencing PHA/PHB purification protocols (e.g., Chen Guoqiang's publications). The likely issue is insufficient biomass yield. If PEAs constitute just 1% of dry weight (already a high estimate), 300 mg of biomass would yield only 3 mg of PEAs—nearly all lost during purification, leaving little to harvest.

2. Pathway Optimization Dilemma: BL21's metabolic regulation mechanisms may impact pathway efficiency, urgently requiring expert guidance.

Response: I'm not entirely clear on this question. Are you aiming to enhance PEAs synthesis efficiency through metabolic engineering? Unfortunately, I haven't seen your metabolic pathway diagram, and as I'm not an expert in this field, it's difficult to provide specific advice. Regarding the project's overall concept, I think it's excellent—degrading waste plastics and converting them into valuable products is a hot research topic in recent years. You've likely seen this year's Nature Chemistry paper converting TPA into acetaminophen (a painkiller). Personally, I believe pursuing high-value TPA derivatives would be challenging to achieve significant breakthroughs. Given limited time and resources, prioritizing microbial utilization of EG would make for a stronger narrative.

II. Core Questions for Your Guidance

1. Metabolic Pathway Construction:

We constructed the EG→PEA pathway in BL21(DE3) based on the gcl/hyi/glxR/glxK genes but failed to detect the expected product. Beyond these core genes, do you believe we should also consider cofactor balance (e.g., NADPH supply) or pathway competition (e.g., glycolic acid diversion)?

Response: Reading this confirms my suspicions (The extraction issue is a separate matter). Using EG as the sole carbon source for PEA synthesis is inherently challenging. First, consider your background statement: “Wild-type E. coli MG1655 can efficiently metabolize EG through heterologous or high-level overexpression of key enzymes like gcl and hyi. However, whether the industrially common expression host BL21(DE3) naturally possesses the same metabolic potential remains unsystematically reported.” Therefore, can the E. coli BL21(DE3) strain you used utilize EG for survival? Secondly, regarding the undetected expected products, we recommend stepwise troubleshooting: 1) Verify whether all transferred genes are expressing normally; 2) Confirm synthesis of intermediates and precursors along the ideal pathway. Coenzyme supplementation and competitive pathway optimization should be addressed after resolving these foundational issues during metabolic flux optimization.

2. Product Detection Methods:

PEAs are easily confused with polyesters. We currently use Nile Red staining for qualitative detection. How should we design a specific detection protocol to avoid false positives? Do you have recommended methods for extracting and quantifying intracellular PEAs?

Response: Without knowing the specific PEA to be synthesized, we recommend establishing detection methods for monomers first, as HPLC offers greater precision. Polymers may complicate extraction and quantification due to solubility issues, but focusing on extraction concerns before establishing metabolic flux is premature.

3. Strain and Induction Optimization:

The T7 background expression in BL21(DE3) may cause excessive metabolic load. Do you think adjusting IPTG concentration or temperature is necessary for expression optimization? Additionally, could BL21's weak EG metabolism be due to endogenous metabolic inhibition? Would you recommend enhancing efficiency by knockout of certain metabolic bypass genes?

Response: These factors could indeed impact metabolism, but each situation requires individual analysis. I did not observe protein expression gel images in your presentation, making it difficult to assess expression levels. Moreover, your current challenge is addressing fundamental issues (0 to 1), while these optimizations pertain to refinement (1 to 100). I believe it is premature to expend resources on such details before identifying the root cause of failure. Clarify your approach and pinpoint the problem before pursuing solutions. Finally, I recommend strengthening the logical flow and structure of your presentation.

We understand your research commitments are demanding, yet we sincerely hope you can spare time to guide our project. Any advice would greatly benefit our work. Should you require further project details, we are ready to provide them. With your permission, we would like to share your guidance on our team Wiki, acknowledging it as “Guidance provided by Professor Li Tao, Guang'anmen Hospital, China Academy of Chinese Medical Sciences” to express our gratitude and respect.

We sincerely appreciate your time and consideration! We look forward to your response.

Sincerely,

iGEM Team, University of Electronic Science and Technology of China

Human Practices Lead: Gu Yuming

Phone/WeChat: 17360289735

September 17, 2025

Attachment 7

Maike Gaocai Interview Summary

Core Q&A Summary + Key Takeaways Summary

I. Core Q&A Summary

Q1: Maike High-Tech Materials possesses years of technical expertise in biodegradable materials, with its official website stating “redefining material lifecycles through green technology.” The National Development and Reform Commission's “14th Five-Year Plan Action Plan for Plastic Pollution Control” mandates promoting resource utilization of plastic waste. In your view, what is the most critical breakthrough needed in current plastic pollution control: source reduction, enhancing degradation efficiency during processes, or high-value resource recovery of waste? Could you share your practical observations? [Most Critical Breakthrough Areas in Plastic Pollution Control & Practical Observations]

Interviewee's Perspective: Policy support continues to intensify; dual-track advancement

Approaches vary across product segments. For degradable packaging materials and agricultural films, current efforts primarily advance through “source reduction + process degradation.” The state promotes recyclable and degradable materials via subsidies and policy guidance, with greater emphasis on recycling infrastructure while actively guiding degradation technologies. However, given the severity of plastic pollution, long-term policy support and investment in biodegradation will intensify.

Q2: Your company's Fengwang fully biodegradable mulch film—a domestic first and internationally leading innovation—offers significant environmental advantages over traditional films. It eliminates agricultural “white pollution” at the source, effectively reduces microplastic contamination of soil and water resources, and improves soil health. We are exploring converting PET degradation products into polyamide (PEAs) polymers. Yet external debate persists regarding the “economic viability of bio-based recycled plastics.” What does your company identify as the core barriers to large-scale adoption of this technology: conversion costs, end-market acceptance, or lack of policy incentives? 【Core Barriers to Large-Scale Adoption of Bio-Based Recycled Plastics】

Interviewee's Perspective: Market acceptance hinges on quality and cost validation through authoritative documentation.

Core barriers center on two points: 1. Conversion Costs: Compared to traditional materials, bio-based recycled plastics carry higher costs. End-users often evaluate costs from a single-process perspective rather than the entire supply chain, necessitating enhanced guidance. 2. Market Acceptance: This fundamentally relates to safety acceptance. While packaging materials face minimal controversy, products like agricultural films and mineral water bottles—which have indirect environmental or human health implications—require data accumulation through pilot and intermediate trials to verify safety for soil and crops (e.g., yield impact). Post-application, technological consolidation is essential.

Q3: How does your company highlight the environmental benefits of this mulch film in promotional materials? Specifically, how do you communicate its eco-friendliness and safety to the public? Are there communication strategies you can share to address public concerns about the safety and efficacy of biodegradable products? Do you believe such strategies could help boost sales of green materials? [Communication Strategies for Mulch Film Environmental Benefits and Their Impact on Sales]

1. Respondent's Perspective: “Authoritative Certification + Accessible Science Communication” Model

Approaches to promoting environmental attributes:

1. Complete full-industry-chain testing with reports issued by CNAS-accredited institutions to verify pollution-free processes.

2. Collaborate with universities and national agricultural technology promotion centers through industry-academia-research partnerships to obtain national-level application validation.

3. Communicate key safety aspects through accessible formats (e.g., short videos) to enable public understanding (e.g., absence of small molecule release).

Impact on Sales Channels: These strategies effectively alleviate public concerns and enhance recognition, thereby boosting sales; however, large-scale, sustained sales growth depends on market maturation.

Q4: Given that your company's eco-friendly polymeric materials are customized products, do clients emphasize environmental requirements related to product recycling and degradation? If so, how does your company view this trend? In your view, what are the core drivers for enterprises or your company's clients to adopt an environmental technology or product?

(Options: A. Policy compliance B. Supply chain cost reduction C. Technology reserves)

[Customer Environmental Demand Trends & Core Driver Ranking]

Respondent Perspectives: Considered separately by customer profiles

Demand Trends: Clients raising environmental demands is a normal phenomenon in new product promotion, aligning with market acceptance patterns (gradual penetration from “early adopters” to “mass adoption”).

Core Driver Ranking: Policy compliance is the prerequisite, varying by client type—large enterprises prioritize “technology reserves,” while small B2B/B2C clients focus on “supply chain cost reduction.” Strategies must be flexibly adjusted for target clients; no one-size-fits-all approach applies.

Q5: What unresolved or noteworthy biosafety issues does your company identify in current fully biodegradable plastics? Has your company considered biosafety aspects for biodegradable plastics/mulch films? We plan to use engineered strains to convert EG/TPA but have concerns about biosafety and public acceptance. What biosafety aspects should we prioritize? How can we educate the public on biosafety to alleviate concerns? 【Biosafety Concerns and Public Education Recommendations】

Respondent Perspective: Dual Approach of Authoritative Testing and Public Awareness

Safety of mainstream materials is validated: National authorities have thoroughly validated current mainstream biodegradable materials (e.g., mulch films, packaging films) and all supply chain segments (upstream material suppliers, midstream manufacturers). Leading enterprises' upstream materials have passed national project approvals, and midstream manufacturers have not encountered biosafety issues to date. For synthetic R&D involving entirely novel materials (without precedents or corporate practice), biosafety must be a core consideration, integrated into the evaluation system from the initial R&D stage. As projects fall under the broad food industry sector, biosafety is an absolute red line. Product architecture design and validation protocols must strictly adhere to safety assessment standards throughout the entire process. Complete full-process testing and obtain authoritative certification to demonstrate process and product safety. Collaborate with leading enterprises or national institutions to secure official reports or certifications through application validation, enhancing credibility. While safeguarding technical confidentiality, use accessible formats like short videos to clearly illustrate core aspects (e.g., “no release of toxic small molecules,” “fully eco-friendly process”) enabling the public to intuitively grasp process safety. Break down the process for public education, emphasizing the core conclusion of “safety and environmental protection” to aid rapid public recall and avoid trust barriers caused by complex technical reports. Authoritative testing reports and collaborative endorsements form the foundation, while accessible public education is key to driving public acceptance—both must work synergistically.

Q6: If our technology can add value per ton of PET waste compared to incineration power generation while reducing carbon emissions, how would you suggest conveying this “environmental protection equals economic benefit” narrative to the public? How should we promote the project's value from an environmental perspective? [How to Communicate the “Environmental Protection Equals Economic Benefit” Project Value]

Respondent's Perspective: Focused Communication (Optimizing Messaging Pathways)

Calculate full-industry-chain costs and carbon emissions: Clearly demonstrate cost reductions, carbon savings, and energy savings compared to traditional methods (e.g., incineration for power generation), establishing a comprehensive “environmental protection - profitability” logic. Refine Core Selling Points: Concentrate on public-focused key messages like “cost savings” and “carbon reduction.” Combine these with comprehensive cost-benefit analysis to demonstrate through concrete data that “environmental protection and profitability can be achieved simultaneously.” Avoid information overload, enabling the public to quickly grasp the “tangible value delivered by environmental protection.”

Q7: Just as your company enhances plastic performance through material modification technology, we reconstruct the plastic lifecycle using synthetic biology. Among the high-value products derived from our waste PET conversion project are polymers like PEAs—fully biodegradable materials sourced from bio-based feedstocks (e.g., microbial fermentation of sugars, fatty acids, EG). Could these serve as raw materials for your company’s eco-friendly polymer production? [Can PEAs be incorporated into green polymer production?]

Respondent's perspective: Prerequisite for commercial collaboration: Practical validation

As an industrialization platform for polymer materials, our company is committed to commercializing original technologies and welcomes expanding into green materials. However, this requires a complete industrialization process: progressing from laboratory pilot tests, through intermediate trials and trial production, to large-scale manufacturing (each stage with distinct equipment requirements) to achieve practical implementation.

Q8: We aim to integrate corporate insights into our iGEM Global Finals proposal, showcasing a “Chinese innovation + industrial insight” approach to plastic governance. As an industry pioneer, what advice would you offer young research teams? How should technical idealism be balanced with industrial pragmatism? [Advice for Young Research Teams and Balancing Technology with Industrialization]

Interviewee's Perspective: Message: The nation is supporting hard technology, with research funding increasingly directed toward young researchers. Youth teams should seize innovation opportunities to contribute to societal and economic transformation. Balancing Advice: Technological idealism and industrial pragmatism must develop synergistically. Universities should uphold technological idealism to drive original breakthroughs while integrating industrial perspectives (e.g., cost, market demand) to avoid detachment from reality. Industrialization processes must respect technological principles to achieve two-way synergy.

Supplementary Discussion Points 1. PEAs Application Reference: Review annual reports and project disclosures of relevant listed companies to understand leading enterprises' technological reserves and efficiently expand ideas. 2. Market Prospects for Degradable Plastic Bottles: Evaluate from an engineering perspective, emphasizing pilot-scale feasibility and intermediate-scale stability verification. Core focus should be on economics (costs must remain within reasonable ranges and decrease progressively with scaling). 3. Common Industrialization Pitfalls: Challenges include production feasibility, scaling capabilities, cost-effective manufacturing, and quality stability. Comprehensive planning across the entire process is essential.