Researchers use algae to remove microplastics from water sources and upcycle them into new biomaterial product.
By Adelaide Levenson
“Microplastics” is a term you might be hearing more and more often these days. A lot of the time, this might be in reference to health or pollutants. With the awareness of microplastics on the rise, there is an increased interest in keeping these particles out of our bodies, water sources, and ecosystems. Aware of the need for microplastic management, a team of researchers at the University of Missouri have developed a system that utilizes algae to remove microplastics from water and convert them into a new biomaterial.
Microplastics, macro-problem
These days, plastics are everywhere. Due to their lightweight nature and cost-effective production, they frequently appear as food packaging and single-use items. At the end of their use, many of these plastics end up as pollution in our ecosystems. Some of this pollution exists in the form of microplastics—plastic pieces smaller than 5 mm (roughly the size of a pencil eraser). This could include chips, fibers, or beads.
Microplastics can be further broken down into two categories: primary and secondary. Primary microplastics include all plastic particles that were manufactured in this form (e.g., pellets). Primary microplastics are commonly found in cosmetics and cleaning products. Secondary microplastics are pieces of larger plastic that have broken down into smaller pieces (e.g., small pieces of vehicle tires that wear off due to usage).
Unfortunately, microplastics aren’t just polluting bodies of water and other ecosystems. They have also been found in drinking water, as well as some foods, including honey, table salt, and commercially processed fish. It’s important that we find a solution to keep microplastics out of these environments.
Attracting microplastics like magnets
To date, the most typical methods of microplastic removal have involved filtration. Unfortunately, this method is costly and prone to clogs. It also is less effective for smaller-sized microplastics. Even when these approaches are effective, what happens to the collected microplastics?
The University of Missouri researchers saw the opportunity to develop a system where microplastics are not only removed from water, but are then turned into something new. This would simultaneously upcycle the collected microplastics while preventing their re-release into the water.
The method that the research team presented in this work was inspired by the hydrophobic nature of microplastics. Hydrophobic (hydro = water, phobic = fearing) describes substances that do not mix with water. Instead, they repel it. When multiple hydrophobic substances are present in water, they are attracted to each other like magnets. This is because hydrophobic substances are more attracted to each other than they are to water.
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Designing a hydrophobic system
Therefore, when designing a new method for microplastic removal, the scientists knew that they also wanted their system to be hydrophobic. This would create the “magnet” for the microplastics. For this reason, they chose a strain of algae that they engineered to be very hydrophobic. They proposed that the algae would attract the microplastics and then sink to the bottom of their water sample. This makes removal of the algae/microplastic mixture easy and efficient.
After designing their algae “magnet” system, it was time to put it to the test. They began by looking at the collection of polystyrene (PS) microplastic on the algae in water. As they suspected, the algae attracted the PS microplastic and then sank to the bottom of their sample. In just one hour, the algae removed 91.4 percent of the PS microplastic from the water.
The next step was to try out different microplastics. They conducted the same experiments with different sizes and types of microplastics, including polyethylene (PE) and polyethylene terephthalate (PET). Just like with PS, they saw interactions between the algae and PE and PET. This proved that the algae can be used for a wide spectrum of microplastic compositions and sizes.
Real-world application
Once they had determined that their system worked, the research team decided to apply it to real-world applications. They started with using the algae to capture microplastics in wastewater. In this application, the algae system could remove both microplastics and excess nutrients from the water. This included nitrate, a nutrient that is typically challenging to remove from water sources. The wastewater samples produced similar results to their previous experiments: the algae again attracted the microplastics. The researchers could then collect the algae and microplastic mixture from the bottom of their wastewater sample.
So, now that the algae has successfully captured the microplastics, what happens next?
Previously, the collected microplastics would need to be stored somewhere and then processed further. Instead, the research team wanted to have their system go one step further: upcycling. Using the mixture of the algae and the collected microplastics, they were able to produce a bioplastic. Compared to the original PS plastic, the bioplastic (algae + PS) had different properties, including an increased toughness. The production of a new material from microplastic pollutants is an exciting development. It allows the research group to tackle more than one challenge at a time!
This research work lays a solid foundation for the upcycling of microplastic pollutants. In the future, the research team would like to develop this work further to be used in industrial applications. They also would like to test their system in more complex environments. For example, in water sources with more varieties of microplastic and other impurities. For now, this is still an exciting step for upcycling!
This study was published in the peer-reviewed journal Nature Communications.
Learn more about research on microplastics in: Plastic Pollution and the Recyclable Ruse
References
Ho, C. M., Feng, W., Li, X., Ngien, S. K., Yu, X., Song, F., Yang, F., & Liao, H. (2025). Microplastic distribution and its implications for human health through marine environments. Journal of Environmental Management, 382, 125427. https://doi.org/10.1016/j.jenvman.2025.125427
Long, B., Li, Q., Hu, C., Chen, Y., Zeng, Y., Li, W., Pearson, S., Liu, M., Fei, C., Yuan, J. S., & Dai, S. Y. (2025). Remediation and upcycling of microplastics by algae with wastewater nutrient removal and bioproduction potential. Nature Communications, 16, 11570. https://doi.org/10.1038/s41467-025-67543-5
Ziani, K., Ioniță-Mîndrican, C.-B., Mititelu, M., Neacșu, S. M., Negrei, C., Moroșan, E., Drăgănescu, D., & Preda, O.-T. (2023). Microplastics: A real global threat for environment and food safety: A state of the art review. Nutrients, 15(3), 617. https://doi.org/10.3390/nu15030617
Featured image is Professor Susie Dai, whose team engineered the special algae. Credit: University of Missouri.
About the Author
Adelaide Levenson is a chemist and baker with a passion for science communication. Although originally from Rhode Island, she currently resides in Dresden, Germany.
