Engineered Algae Can Remove Microplastics from Drinking Water

Researchers at the University of Missouri have developed a new method to remove microplastics from water. They engineered a strain of algae to capture these tiny plastic pollutants. The goal is to clean waterways and repurpose the collected plastic into bioplastic materials.

Microplastics are pervasive in the environment. They are found in ponds, lakes, rivers, wastewater, and fish. Current wastewater treatment plants often cannot filter out these small particles. This allows microplastics to enter drinking water, polluting ecosystems and potentially harming organisms.

The researchers genetically engineered algae to produce limonene. Limonene is a natural oil that gives oranges their scent. This oil alters the algae's surface properties, making it water-repellent. Microplastics are also water-repellent, so they adhere to the modified algae. This process causes the microplastics and algae to clump together and sink, forming a dense biomass layer that is easier to remove.

These engineered algae also grow in wastewater. They absorb excess nutrients during their growth, further contributing to water purification. This approach addresses three issues simultaneously: microplastic removal, wastewater treatment, and the potential for creating bioplastic products from the collected materials. The research is in its early stages.

The team aims to integrate this process into existing wastewater treatment facilities. This would allow cities to more effectively clean their water and reduce pollution. The researchers are also working to scale up the technology. They use large tank bioreactors, including a 100-liter system called “Shrek,” to process industrial flue gas. Future plans include adapting these larger systems for wastewater treatment and other pollutant removal.

The study, titled "Remediation and upcycling of microplastics by algae," was published in *Nature Communications*.