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Plastic Pollution: The Invisible Epidemic

A severely large amount of plastics are produced with the improvement of technology and living standards.

Global plastics production is predicted to continue to grow in the coming years, reaching around 1.2 billion tonnes in 2060. At the same time, plastic waste management will become a growing concern, with around 250 million tonnes expected to be generated by 2025.^[1]

The massive global reliance on plastic has created an environmental crisis, contaminating our oceans, soil, and even the air we breathe. Millions of tons of plastic waste enter marine ecosystems every year, where marine life mistakes it for food or becomes fatally entangled.

Over 914 marine species have been documented to be entangled by or ingest plastic in 2015, with the frequency of occurrence being highest among turtles.^[2] The number of affected species has increased to more than 1000 since then.^[3]

This leads to biodiversity loss and consequently disrupts the food chain of aquatic species that rely on eating other marine animals. On land, microplastics have seeped into agricultural soil and contaminated crops, polluting the cycle of the human food supply. In the air, microplastic particles can enter our lungs, which results in respiratory risks such as inflammation and chronic conditions such as asthma.^[4]

Meanwhile, landfills overflow with plastic, which may take centuries to degrade. These plastic waste continuously leach harmful chemicals into groundwater, while incineration releases toxic gases such as dioxins and furans into the atmosphere, resulting in air pollution. This unsustainable cycle demands urgent solutions: Innovative approaches that can break down plastic safely, without relying on energy-intensive processes or releasing deadly byproducts. The future of our ecosystems, wildlife, and human health depends on how we manage plastic waste before its consequences become irreversible.

Why is a new solution to plastic accumulation needed?

Conventional plastic treatment methods are severely limited by the material's extreme resistance to natural decomposition. Landfilling requires at least 450 years for plastic to break down. As a result, incineration is often used, but this process demands dangerously high temperatures of 450°C to 750°C. This consumes vast amounts of energy, worsens global warming, and releases toxic gases like carbon monoxide, sulfur dioxide (SO₂), and chlorofluorocarbons (CFCs). These emissions contribute to acid rain, ozone depletion, and pose severe health hazards for nearby communities.

Chemical recycling, including pyrolysis and gasification, is often presented as an alternative. However, it also requires extreme heat (400-1500°C) and high energy use, yet yields a meagre 10-30% reusable output. The process generates toxic byproducts like dioxins and heavy metals, creating significant health hazards. Furthermore, most projects are economically unviable, relying on subsidies while processing less than 2% of global plastic waste. This makes it a greenwashed approach, underscoring the fact that reducing plastic production and improving real recycling remain more critical solutions.

Traditional mechanical recycling, widely promoted as eco-friendly, suffers from critical limitations. The process results in "downcycling," where plastics like PET deteriorate in quality with each cycle, eventually becoming unusable—for example, a clear water bottle is often transformed into lower-grade polyester fiber before becoming waste. Only about 9% of all plastic ever manufactured has actually been recycled, with the vast majority ultimately discarded in landfills or incinerators.

The system also faces fundamental economic challenges. Food contamination and mixtures of incompatible polymer types make many plastic products too costly or technically difficult to recycle properly. These inherent flaws reveal why mechanical recycling cannot single-handedly solve the plastic pollution crisis, necessitating more comprehensive approaches that prioritize reduction and reuse.

Our Project

To alleviate the problem of plastic pollution and mitigate the serious impacts made by plastic on our environment, our team is working on multiple DNA combinations to break down PET.

PET is a major kind of plastic found in the sea and is a common material for bottles, largely contributing to plastic waste. We are inspired by the excellent project made by the Waseda Tokyo iGEM Team^[5] in 2024, which utilises the CsgA gene with different kinds of PETase, to enhance breakdown efficiency. We decided to further investigate the work by utilising HotPETase, a more thermostable PETase variant, and adding a new gene, BaCBM2, which further enhances the fusion protein's thermostability and anchors the entire complex to cellulose-based materials.^[6]

CsgA constructs curli fibres on the surface of the E. coli membrane, enabling whole-cell biocatalyst development and displaying PET-binding domains or enzymes like HotPETase,^[7] while the Bacillus anthracis Carbohydrate-Binding Module 2 (BaCBM2) was fused to the C-terminus of HotPetase to construct the Petase mutant (HLCB) for increased degradation through improved substrate binding.^[6]

Our Vision

The core objective of our project is to enhance the efficiency of PETase enzymes to efficiently accelerate PET plastic degradation. Through synthetic biology, we aim to develop innovative biological solutions that can break down plastic waste in weeks rather than centuries.

Simultaneously, we recognise that technological advancement must be paired with social engagement. We are committed to raising public awareness about plastic pollution's devastating impact on ecosystems, wildlife, and human health. Through educational initiatives and exchange partnerships, we strive to inspire behavioral change and promote sustainable practices.

Our approach combines cutting-edge science with meaningful human practices—educating students, collaborating with researchers, and engaging policymakers. We believe that lasting solutions require both biological innovation and social transformation.

References

[1] Grattagliano, A., Grattagliano, Z., Manfra, L., Libralato, G., Biandolino, F., & Prato, E. (2025). An Overview on Microplastics Hazards to the Marine Ecosystem and Humans’ Health. Water, 17(7), 916. https://doi.org/10.3390/w17070916

[2] Susanne Kühn, Jan Andries van Franeker Quantitative overview of marine debris ingested by marine megafauna (2019). https://doi.org/10.1016/j.marpolbul.2019.110858

[3] Condor Ferries Marine & Ocean Pollution Statistics & Facts (2025). https://www.condorferries.co.uk/marine-ocean-pollution-statistics-facts

[4] Joana Correia Prata Airborne microplastics: Consequences to human health? (2017). https://doi.org/10.1016/j.envpol.2017.11.043

[5] Waseda Tokyo iGEM Team. (2024). Waseda Tokyo iGEM 2024: Engineering Curli Fibers to Enhance PET Degradation. https://2024.igem.org/Team:Waseda_Tokyo/Human_Practices

[6] Wang, T., Yang, W., Gong, Y., Zhang, Y., Fan, X., Wang, G., Lu, Z., Liu, F., Liu, X., & Zhu, Y. (2024c). Molecular engineering of PETase for efficient PET biodegradation. Ecotoxicology and Environmental Safety, 280, 116540. https://doi.org/10.1016/j.ecoenv.2024.116540

[7] Waseda Tokyo iGEM Team Design (2024) https://2024.igem.wiki/waseda-tokyo/design/