Overview
1. The Problem: A Planet Choking on Dual Waste Streams
Our modern world is facing two parallel and escalating environmental crises: plastic pollution and food waste.
- The Plastic Dilemma: Polyethylene terephthalate (PET) is one of the most prevalent synthetic plastics, with global production projected to reach a staggering 35.13 million tons by 2030. Tragically, recycling rates remain dismally low, particularly in developing countries, where only about 20% of PET is recovered. Conventional recycling methods, like mechanical and thermal processes, often result in down-cycled materials with inferior properties, failing to establish a true circular economy.
- The Food Waste Crisis: Simultaneously, approximately one-third of all food produced for human consumption is lost or wasted annually. A significant portion of this—about 23%—is starch-rich kitchen waste. Current valorization strategies, such as anaerobic digestion, often yield low-value products or require complex and costly processes, leaving vast potential for resource recovery untapped.
These two waste streams represent not just an environmental burden but also a massive untapped resource, if only we could transform them efficiently and sustainably.
2. Our Solution: From Trash to Treasure via Synthetic Biology
Inspired by the principles of the circular economy, our team, BUCT-China 2025, proposes a novel integrated solution: “Enzymatic Upcycling of PET Waste and Kitchen Waste to Supramolecular Phosphorescent Materials.”
We have designed a synergistic biotechnological platform that concurrently addresses both PET and starch waste, converting them into a single, high-value product. Our vision is to create a "Win-Win-Win" scenario: a win for the environment by reducing waste, a win for the economy by creating valuable materials, and a win for society by promoting sustainable practices.
3. Our Workflow: A Two-Stream Conversion Process
Our project leverages the power of engineered enzymes to create a seamless upcycling pipeline:
- Stream 1: Transforming PET Bottles into a Luminescent Precursor.
We employ the highly efficient TurboPETase to depolymerize waste PET plastics under mild conditions. This enzymatic hydrolysis yields TPA (terephthalic acid), which we then chemically convert into a novel derivative, PPA, designed to be the ideal guest molecule for our final assembly. - Stream 2: Valorizing Kitchen Waste into a Molecular Host.
We utilize Cyclodextrin Glycosyltransferase (CGTase) to bioconvert starch from food waste into β-Cyclodextrin (β-CD). β-CD is a cyclic oligosaccharide renowned for its unique ability to form host-guest complexes, serving as the perfect molecular container.
Final Assembly: Creating a Novel Functional Material.
The magic happens when PPA and β-CD are combined. Through spontaneous supramolecular self-assembly driven by host-guest interactions, they form a stable complex: PPA-CD. This PPA-CD complex exhibits remarkable room-temperature phosphorescence (RTP), a rare and valuable optical property with applications in anti-counterfeiting, bio-imaging, and sensors.
Proposed End Users
Our project is driven by a commitment to real-world application. Through direct engagement with potential end-users and advisors, we have refined our implementation strategy to focus on three key groups. Their feedback has been instrumental in shaping a path from laboratory validation to tangible impact.
1. The Hospitality Industry: Our Initial Demonstration Platform
Primary End Users: Medium to high-end hotels and resort chains.
Their Need & Our Solution: Hotels are increasingly seeking innovative ways to demonstrate their commitment to sustainability while also managing operational costs. Our interviews revealed that a tangible, functional prototype is the most powerful tool for communication and buy-in. Therefore, we will directly address this by creating immediate value through customized, sustainable materials.
2. The Art and High-End Design Sector: Building a Premium Brand Narrative
Primary End Users: Artists, designers, and manufacturers of luxury goods, decorative items, and corporate branding materials.
Their Need & Our Solution: This market values uniqueness, storytelling, and sustainable provenance. The advice from the corporate vice chairman highlighted that our material’s journey from "waste to wonder" is a powerful narrative asset. We will position PPA-CD not just as a material, but as a story that adds brand value and exclusivity.
Ongoing Effort: Secure Authoritative Data. While our initial attempts to gather specific governmental data were met with confidentiality barriers, we recognize its importance for large-scale credibility. We will continue to seek opportunities to collaborate with government-backed environmental projects to obtain authoritative validation and data in the future.
3. Governmental and Large-Scale Waste Management Entities: Laying the Groundwork for Systemic Impact
Primary End Users: Municipal environmental protection bureaus and large waste management companies.
Their Need & Our Solution: These entities are responsible for meeting recycling targets and managing urban waste streams efficiently. They require robust, data-backed proof that a new technology can handle the complexity and scale of real-world waste before considering adoption or support.
Envision
The successful creation of our PPA-CD material is not an end, but a beginning. It validates a powerful paradigm: waste streams can be the primary feedstock for advanced functional materials. To fully realize this vision, our future work will advance along two parallel tracks:
1. Experimental Vision: Building a Comprehensive "Waste-to-Wealth" Enzyme Toolkit
While our current system efficiently utilizes PET and starch, we plan to dramatically expand the scope of processable waste by developing and integrating a broader suite of enzymes. Our goal is to create a modular platform where different waste inputs can be channeled into the production of valuable outputs.
Expanding Plastic Depolymerization: We will explore enzymes capable of degrading other prevalent plastics beyond PET.
- Target: Polyethylene (PE) and Polyurethane (PUR).
Approach: We will mine and engineer PE-degrading enzymes (e.g., PEase) and urethanases. The resulting monomers, such as fatty acids and diols, can be used either as alternative building blocks for new supramolecular materials or as carbon sources for supporting microbial growth in our fermentation processes. We will harness enzymes to break down the other major components of kitchen waste, unlocking their potential. - Target: Cellulose and Lipids (oils & fats).
Approach: We will employ cellulases to break down cellulose into glucose. This glucose syrup can serve as a low-cost nutrient for fermenting our CGTase-producing bacteria, thereby closing the loop and reducing production costs. We will utilize lipases to hydrolyze waste oils into glycerol and free fatty acids. Glycerol is an excellent carbon source for microbial fermentation, while fatty acids can be functionalized into novel guest molecules for developing next-generation supramolecular materials.
This integrated, multi-enzyme approach will allow us to create a synergistic system where multiple waste streams are not a burden, but a diversified portfolio of raw materials, making the entire process more robust and economically attractive.
2. HP & Industrialization Vision: Forging a Complete Circular Economy Chain
Transforming a laboratory innovation into a societal solution requires meticulous planning and integration across the entire value chain. Our human practices guide us to build a sustainable ecosystem around our technology.
Diversifying Feedstock Sources & Applications:
We will proactively partner with waste management companies and municipal governments to secure a stable and diverse supply of raw materials (PET, food waste), turning a cost center for cities into a revenue stream.
We will deepen our engagement with the security printing and luxury packaging industries to co-develop and test anti-counterfeiting inks and tags based on PPA-CD. The unique, sustainable origin of our material creates a powerful brand story alongside enhanced security.
Building the Integrated Industrial Chain:
Upstream: Establish long-term contracts with waste providers and enzyme manufacturers to ensure supply and scale-up production.
Midstream: Build or partner with a biorefinery that integrates the enzymatic degradation of waste and the synthesis of PPA-CD, serving as the central processing hub.
Downstream: Develop strong relationships with product manufacturers in the security, design, and electronics sectors, transforming our PPA-CD powder into commercially ready products like security labels, designer paints, and sensor films.
By systematically connecting these upstream, midstream, and downstream elements, we will transition from a technology provider to a key player in a new circular materials economy. Our ultimate vision is to see our technology serve as a replicable model, turning the linear "take-make-dispose" paradigm into a circular "waste-value-application" loop, ultimately benefiting the environment, the economy, and society at large.
Implement
Based on our integrated experimental and human practices work, we have successfully established a complete pipeline to convert PET and kitchen waste into supramolecular phosphorescent materials. Experimentally, we completed the entire workflow and conducted iterative optimizations, primarily focusing on enzyme performance, to efficiently transform waste into our target PPA-CD product. In parallel, our human practices research involved comprehensive stakeholder engagement—including industry professionals, potential end-users, and academic advisors—whose valuable feedback was directly incorporated into our experimental design. Furthermore, we placed a strong emphasis on inclusivity, ensuring our project considered and engaged diverse groups throughout its development and implementation.
Safety Considerations
Safety has been a foundational principle throughout our project, rigorously applied in both our laboratory work and human practices. In the lab, we adhered to strict biosafety protocols by using non-pathogenic, engineered E. coli strains with auxotrophies to prevent environmental persistence. All waste was inactivated prior to disposal, and personal protective equipment was mandatory, ensuring a safe research environment. For our human practices, we proactively identified and addressed potential ethical and social concerns by conducting inclusive stakeholder interviews with industry professionals, community members, and experts. This process was guided by principles of equity and responsibility, ensuring our technology’s development remained transparent, responsive, and accessible to diverse groups, thereby aligning our innovation with broader societal values.
Challenges
Throughout our project, we navigated and addressed several critical challenges spanning both technical and social dimensions. A primary technical hurdle was the optimization of enzyme performance, particularly in handling the complexity and variability of real-world waste streams, which required iterative experimentation to achieve efficient conversion. Simultaneously, aligning the diverse needs and expectations of our stakeholders—from hotel managers seeking tangible prototypes to corporate partners emphasizing brand narrative—posed a significant human practices challenge, demanding careful balancing of functionality, aesthetics, and economic viability. Furthermore, ensuring the project's safety and inclusivity required the implementation of stringent lab protocols and the proactive engagement of diverse groups, integrating their feedback to responsibly guide our technology’s development toward broad and equitable application.