Vision and Outlook

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Introduction


Plastic waste, and especially microplastic contamination, remains one of the most pressing environmental issues. The United Nations Environment Programme (UNEP) emphasised this urgency at the Intergovernmental Negotiating Committee on Plastic Pollution in August 2025, where global leaders reaffirmed the importance of scalable and sustainable solutions (BBC News, 2025). However, such policymaking and other reduction efforts are far from being implemented effectively. For one, we learn from the various stakeholders, through our self-conducted study, that in places like Thailand, recycling and waste logistics are still fragmented, incentive‑poor, and simply ineffective. Therefore, while various reduction efforts will continue to be promoted, innovative technologies to effectively address plastic pollution must also be developed to ensure the long-term health of our planet. For us, we hope to create a platform that will lead to a plant-based water filtration system, which will allow for direct bioremediation. Such a project will fill in the missing gap—a method to get rid of existing or soon-to-exist plastics. As such, this project will ultimately lead to a reduction in plastic pollution across water ecosystems and, by extension, in plants, animals, and other environmental factors, both biotic and abiotic.

Our Outlook


What we are doing


The current construct expresses PETase fused to an alpha‑amylase signal peptide to drive trafficking through the secretory pathway and accumulation in the apoplast, leveraging established alpha‑amylase targeting and extracellular localization in plants. Additionally, a genetic kill-switch system, a stable transformation attempt, and a protein function test have also been developed to ensure the mentioned benefits, though they are not successful yet.

The Future of Our Project (Our Outlook)


The envisioned large-scale system uses living plant beds as filtration media, akin to constructed wetlands. Such vision is highly noteworthy, as not only is it low-cost, low-energy, and safe, but it also aligns with Thailand's and most countries’ laws against the free release of GM plants into open environments (Napasintuwong, 2020). Through this vision, our team has also developed a potential business model of how the system will work. Please refer to the entrepreneurship page for more information.

Looking ahead, we also see repolymerization as another option for our future products. The eventual product of PETase hydrolysis—ethylene glycol (EG) and terephthalic acid (TPA)—can be captured and purified as feedstocks to make new PET, rather than relying on today’s imperfect recycling streams and continual virgin plastic production (Gowda et al., 2023). This approach gives the system two viable end‑points: bioremediation to mineralized, non‑toxic outputs and circular re‑entry where EG/TPA are recombined into PET under controlled industrial conditions, reducing dependence on fossil inputs and leakage from inefficient sorting and mechanical processing.

How we will do it


With this outlook, we divide our vision into three steps:

  1. Prove that PETase can be expressed and secreted in a plant.
  2. Develop our PET decomposition system so that it is functional, efficient, and safe.
    1. Protein function test
    2. Secretion tuning
    3. Experimentation of PETase variants
    4. Expression targeting
    5. Kill-switch validation
    6. Track byproduct fate and enable circular capture
    7. Stable Transformation
  3. Migrate our model for higher-efficiency plants to test for real-world implications.
    1. Migrate from a lab plant like N. benthamiana to a plant that has a high transpiration rate, like water hyacinth (CĂĄrdenas-Cuadrado et al., 2025)
    2. Pilot columns: build bench-scale beds for future tests.
    3. Lifecycle metrics: compare energy use and environmental impact

Step 1 - Expression and secretion proof


For this year’s project, our project milestone is to show that PETase can be expressed in a plant and secreted outside the cell, using N. benthamiana as a familiar, fast, and safe host for transient expression. This task establishes whether our plant-based plastics filter vision has potential or not. If our team is unable to express PETase in the plant, we will need to relaunch the entire process. Similarly, if the enzyme cannot be routed through the secretory pathway and accumulates in the apoplast, where it can actually meet microplastics rather than being trapped inside cells, a similar major restructuring would have to occur. Therefore, the entirety of this step is to prove this concept.

  • Success of this step looks like clear detection of PETase in extracellular fractions in comparison to a negative control (no-signal peptide vector).
  • Based on our localization results, this step is successful. See Engineering and Results for secretion fractionation, apoplast extraction, and controls.

More detail on step one is provided on the engineering, experiment, and result pages.

Step 2 - Functional, efficient, and safe


With expression and secretion in hand, the next move is to prove the enzyme actually works where it matters, tune how and where it’s produced, and lock in clear safety controls before committing to long‑lived lines. This stage first uses transient expression in N. benthamiana to quickly iterate on activity, secretion, and biosafety. Then, stable transformation will be the next move once the design shows reliable performance and manageable byproducts under plant-compatible conditions.

  1. Protein function: confirm that secreted PETase degrades PET in the extracellular space under realistic temperature and pH for plant tissue. This stage uses HPLC to quantify PET hydrolysis products—MHET/BHET—against standards to identify protein function.
    • We have started this stage, but with no success thus far.
  2. Variant testing: compare I. sakaiensis PETase with improved options such as FAST‑PETase to increase degradation efficiency.
    • PETase variants are deferred to maintain focus on secretion and safety. Additionally, I. sakaiensis PETase was proven to be functional against post-consumer plastics in photosynthetic microalgae (Di Rocco et al., 2023), the main evidence that supports this research.
    • Plant-secreted targeting data and stability will gate variant adoption
  3. Expression targeting: dial promoter strength and tissue specificity.
    • This step may include switching from an all-rounder overexpression promoter to a more benign root-specific promoter as recommended by our discussion with the NSTDA. By doing so, our plant would only secrete PETase where PET particles are most likely to accumulate, lowering plant fatigue.
    • It must be noted that the promoter selection will be evaluated depending on the plant host option in step 3.
  4. Kill-switch validation: test red-light-inducible lethality circuits under defined conditions to demonstrate a reliable shutdown path if plants leave controlled installations.
  5. Byproduct fate: Track and manage PET hydrolysis products during assays to prevent unwanted accumulation and to inform downstream capture or polishing steps. Add MHETase to convert MHET to EG and TPA under plant‑compatible conditions; quantify EG/TPA with HPLC to establish mass balance.
    • If this section shows positive results, we can attempt transferring purified EG/TPA to a contained re‑polymerization through external partners to create recycled‑equivalent PET, replacing part of virgin resin demand.
  6. Once these steps are reproducible, initiate stable transformation to create lines that maintain balanced expression over generations without excessive metabolic burden.
    • From the outset, we have begun testing stable transformation in conjunction with transient tests to learn more about the process, a venture that the Thailand-RIS team has never undertaken before.

Step 3 - Real-world pilots


This last stage connects the lab construct to a contained, modular deployment—the T-RIS Biofilter—so real water, real microplastics, and real operating constraints can come together to guide the final design. Beyond optimizing what has been created in step 2, step 3 may contain plant migration. Currently, tests are run on N. benthamiana. However, plants like water hyacinth serve as a better option, as they are both aquatic and high-transpiration (accumulate plastic particles faster). Especially in the context of Thailand, this plant serves as a suitable implementation of our design.

Through the sustainability lens, such implementation would pave the way for a low-energy and easy-to-steward system, as the biofilter is passive and needs no external power or chemicals, meeting various sustainable development goals. More information can be found on the sustainability page.

Through the entrepreneurship lens, step 3 also doubles as the bridge from science to service. You can find more information about this topic on the entrepreneurship page where business logic and user interviews indicate where and how the system would be adopted.

In terms of scientific practice, this step may include the following investigations:

  • Pilot columns: build bench‑scale, contained tanks planted with engineered hosts expressing a variant of PETase to quantify day‑scale microplastic removal, verify secretion in flowing water, and track byproducts end‑to‑end before any open‑water consideration.
  • Biosafety in practice: combine genetic safeguards (sterility, red‑light kill switch) with physical containment and clear harvest protocols to ensure plants cannot spread beyond installations or persist after shutdown.
  • Optional PET re‑polymerization feasibility: in a contained lab setting and with partners, assess whether captured EG/TPA meets purity specifications for PET synthesis and characterize the resulting polymer (IV, contaminant profile) as a proof‑of‑concept for circular production that avoids inefficient sorting‑dependent recycling.
  • Lifecycle and policy check: compare energy and emissions for capture‑and‑repurpose vs. full mineralization, and map compliance pathways for transporting EG/TPA as chemical feedstocks under Thai GMO constraints (contained facilities, no GM release).

It must be noted that the science described in step 3 is highly speculative. In fact, the majority of such tests are beyond iGEM’s safety limit for high school teams. Therefore, until laws and regulations change, we will adhere to the following measures:

  • Avoid environmental release (in compliance with the current Thai laws)
  • Only perform plant experiment in BSL-appropriate, enclosed facilities
  • PET re-polymerization only with licensed partners and no on-site polymerization by the team.

Conclusion


As we advance through each step, we will continue to fold in stakeholder feedback: for example, NSTDA’s recommendation on root-localized expression informs Step 3’s chassis migration and promoter choices; Dr. Daud’s emphasis on end-of-life risks motivates the ‘byproduct fate’ controls and optional circular capture; and Thailand’s fragmented recycling logistics reinforce the contained, modular deployment model to minimize leakage and regulatory risk.

With this year’s project coming to its end and the success of step 1, step 2’s exploration is soon to develop this project to even greater future heights.

References

  1. BBC News. (2025, August 15). No agreement reached in UN plastic pollution talks | BBC News [Video]. YouTube. https://www.youtube.com/watch?v=wPWSKuTUdgM
  2. CĂĄrdenas-Cuadrado, C., Morocho, L., Guevara, J., Cepeda, M., HernĂĄndez-Paredes, T., Arcos-JĂĄcome, D., Ortega, C., & Portalanza, D. (2025). Modeling the impact of water hyacinth on evapotranspiration in the ChongĂłn Reservoir using remote sensing techniques: Implications for aquatic ecology and invasive species management. Hydrology, 12(4), 80. https://doi.org/10.3390/hydrology12040080
  3. Di Rocco, G., Taunt, H. N., Berto, M., Jackson, H. O., Piccinini, D., Carletti, A., Scurani, G., Braidi, N., & Purton, S. (2023b). A PETase enzyme synthesised in the chloroplast of the microalga Chlamydomonas reinhardtii is active against post-consumer plastics. Scientific Reports, 13(1), Article 37227. https://doi.org/10.1038/s41598-023-37227-5
  4. Gowda, O., Venkatesh C., Kavitha, K., & Uday, J. (2023). Molecular docking analysis of PET with MHET. Bioinformation, 19(3), 255–259. https://doi.org/10.6026/97320630019255
  5. Hampson, M. (2016, March 9). Science: Newly identified bacteria break down tough plastic. American Association for the Advancement of Science. https://www.aaas.org/news/science-newly-identified-bacteria-break-down-tough-plastic
  6. Napasintuwong, O. (2020, July 16). Current status of agricultural biotechnology in Thailand. FFTC Agricultural Policy Platform (FFTC-AP). https://ap.fftc.org.tw/article/1383#:~:text=In%20Southeast%20Asia%2C%20the%20Philippines,crops%20were%20banned%20after%202001
  7. Yoshida, S., Hiraga, K., Takehana, T., Taniguchi, I., Yamaji, H., Maeda, Y., Toyohara, K., Miyamoto, K., Kimura, Y., & Oda, K. (2016). A bacterium that degrades and assimilates poly(ethylene terephthalate). Science, 351(6278), 1196–1199. https://doi.org/10.1126/science.aad6359