A research team at the University of Missouri in the United States recently developed a genetically engineered algae that is expected to efficiently "capture" and recycle harmful microplastics in wastewater treatment, providing a new technological path to deal with this stubborn environmental pollution problem.
The project is led by Susie Dai, a professor in the University of Missouri College of Engineering and principal investigator at the Bond Life Sciences Center. Her team designed a special strain of algae that can bind to microplastic particles in water and separate them from contaminated water. Research not only aims at reducing microplastic emissions, but also attempts to "upcycle" recycled plastics and algae biomass together to prepare new materials such as composite bioplastic films.
Desusi pointed out that microplastics are almost everywhere, from ponds, lakes, rivers to various wastewater systems and even in fish eaten by humans. At present, most sewage treatment plants mainly rely on existing processes to remove larger plastic particles, while tiny microplastics often "slip through the net" and eventually enter the drinking water system, continuing to pollute the environment and harm the ecosystem.
In the latest research, the team used genetic modification to enable algae to synthesize limonene, a natural oil compound that is also the main source of orange flavor. Limonene gives algae significant hydrophobicity, and microplastics themselves also have hydrophobic characteristics, making them easy to adsorb to each other in water. When this engineered algae comes into contact with water containing microplastics, the microplastic particles will "stick" to the algae cells and aggregate into clumps, forming larger flocculent clumps that can be relatively easily separated from the water after settling.
In addition to capturing microplastics, this type of modified algae can also grow well in eutrophic wastewater environments and further participate in the water purification process by absorbing excess nutrients. Daisusi said that through this system, the triple goals of "removing microplastics", "purifying wastewater" and "processing microplastics and algae into useful bioplastic products" can be achieved simultaneously in one process. Although it is still in the early stages of research, the team's long-term vision is to integrate this new process into existing urban sewage treatment plants, so that cities can improve water treatment efficiency and reduce pollution while also obtaining new material products with application value.
To push the technology toward practical applications, the team is conducting scale-up experiments using bioreactors under controlled conditions. One of the 100-upgrade biological reaction systems called "Shrek" has been used to treat industrial flue gases and explore the possibility of reducing air pollution through algae absorption. Looking to the future, the research team plans to build a larger-scale bioreactor device and expand this platform to more scenarios such as wastewater treatment to improve the removal efficiency of various environmental pollutants.