Plastic pollution is a global problem, and much of it comes from polyethylene terephthalate (PET), a common plastic used in bottles, containers, and clothing.
Researchers have now found an enzyme in microbes from wastewater that can break down PET.
This discovery, published in Environmental Science & Technology, could help wastewater treatment plants remove microplastic particles and recycle plastic waste more effectively.
Microplastics, tiny plastic particles, are found almost everywhere, including in oceans, soils, and even inside the human body.
Wastewater also contains these particles, which are too small to be filtered out by most water treatment processes.
However, the wastewater environment also contains microorganisms that can eat plastic particles, including a microbe called Comamonas testosteroni.
Comamonas testosteroni has already been known to degrade various polymers and compounds, such as those found in laundry detergents.
So, a research team led by Ludmilla Aristilde wanted to see if it could also break down PET.
In their study, the team grew a strain of C. testosteroni with PET films and pellets. They found that the microbes preferred the rougher surface of the pellets, breaking them down more effectively than the smoother films.
When the researchers added acetate, a common ion found in wastewater, the number of bacterial colonies increased significantly.
The microbe broke PET down into nano-sized particles and, in some cases, completely degraded it into its building blocks, called monomers. These monomers could then be used by C. testosteroni and other environmental microbes as a source of carbon for growth or even to make useful molecules.
The researchers also identified the specific enzyme in C. testosteroni responsible for breaking down PET. When they transferred the gene for this enzyme into another microbe that doesn’t normally eat PET, the new microbe gained the ability to break down the plastic.
This discovery shows the potential for using C. testosteroni and its enzyme to upcycle PET and reduce plastic pollution in wastewater, offering a promising new way to tackle the global plastic problem.
Source: American Chemical Society.
