Scientists at the University of Missouri have developed a novel algae-based solution that could help tackle one of the most stubborn forms of pollution microplastics in water. By using genetically engineered algae, researchers have demonstrated a way to capture tiny plastic particles that routinely escape conventional wastewater treatment systems and end up in rivers, lakes and even drinking water.
The breakthrough, led by Susie Dai, professor in the College of Engineering and principal investigator at the Bond Life Sciences Center, has been published in the journal Nature Communications. The approach not only removes microplastics from polluted water but also opens the door to reusing the collected plastic waste in safer, value-added products.
Why microplastics remain a hidden threat
Microplastics are now found almost everywhere from freshwater bodies and wastewater to marine life and food consumed by humans. Because of their extremely small size, most wastewater treatment plants are unable to filter them out effectively. As a result, these particles persist in ecosystems, posing risks to wildlife and potentially human health.
Dai explained that current treatment systems are designed to remove larger plastic debris, leaving microplastics free to pass through. Over time, this allows plastic pollution to accumulate across natural and human-made environments, making the need for new solutions increasingly urgent.
How algae capture plastic particles
The new method relies on a specially engineered strain of algae that produces limonene, a natural oil responsible for the citrus scent in oranges. Limonene makes the algae water-repellent, a key property that allows it to interact with microplastics, which are also water-repellent.
When placed in contaminated water, the algae and microplastics attract each other and form clumps. These clumps sink to the bottom, creating a dense layer of biomass that can be easily collected and removed. At the same time, the algae feed on excess nutrients in wastewater, helping clean the water as they grow.
Researchers describe this as a three-fold solution: removing microplastics, treating wastewater and enabling the reuse of plastic waste.
Beyond capturing microplastics, the team is exploring ways to repurpose the recovered material. The collected plastics could be transformed into bioplastic products such as composite films, reducing the need for new plastic production and supporting circular economy goals.
Dai noted that while the research is still at an early stage, the long-term aim is to integrate this algae-based process into existing wastewater treatment plants. If successful, cities could adopt the technology without major infrastructure changes, improving water quality while reducing environmental pollution.
The research team is already working on scaling the technology. Dai’s laboratory uses large tank bioreactors to grow algae and test pollution removal. One such system, a 100-litre bioreactor nicknamed “Shrek,” has been used to process industrial flue gas for air pollution control.
In the future, larger versions of these bioreactors could be adapted for wastewater treatment and other environmental cleanup efforts. Researchers believe this approach could offer a practical and sustainable way to address microplastic pollution at scale.
As concerns over plastic contamination grow worldwide, innovations like algae-based remediation may become an important part of future water treatment strategies, combining environmental protection with resource recovery.