Environment & Climate Change

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Could plastic-eating bacteria be a solution to microplastic pollution?

Michigan Public | By Lester Graham

Published January 12, 2025 at 1:00 PM EST

Before and after side-by-side view. When genetically altered bacteria were put in ideal conditions, they reduced the mass of this plastic lid by 40% in four days. — Before and after side-by-side view. When genetically altered bacteria were put in ideal conditions, they reduced the mass of this plastic lid by 40 percent in four days.

Researchers in Canada have altered bacteria to break down microplastics.

They’ve developed a way through “bacterial sex” to genetically alter bacteria often found at wastewater plants.

“The technology we developed essentially allows us to deliver instructions to environmental bacteria to break down plastics. And in this case, we programmed them to break down PET plastics,” said Aaron Yip, a PhD candidate in the Department of Chemical Engineering at the University of Waterloo.

PET (Polyethylene Terephthalate) is one of the most common kinds of plastics, used in bottles, clothing, carpet, and many other products.

Researchers selected bacteria often found at wastewater plants, because not all microplastics are filtered out before being released into a stream or river.

Already, microplastics are polluting water and getting into fish, animals, and people. Chemicals in plastics are associated with insulin resistance, and decreased reproductive health.

Plastic pieces on the shore of a channel linked to Lake Michigan. With time, wind, waves, and ultraviolet light from the sun will break the pieces down to the microplastic level. Microplastics have been found in tap water, fish, animals, and people.

In one experiment, putting the plastic-eating bacteria in the most ideal conditions, and with researchers' help, the best result showed the bacteria degraded the plastic by 40 percent in four days. In another experiment with less help from the researchers, there was about 2 percent degradation over the course of a week.

“If you think of it in the big picture, where it takes plastic maybe 100 plus years to break down in the natural environment, two percent in a week is actually a really good result,” Yip said.

In a press release from the University of Waterloo, Brian Ingalls, a professor in the Department of Applied Mathematics, said the long-term vision is to break down microplastics in wastewater treatment plants at scale.

There are concerns and questions that need to be answered:

When the plastic breaks down, what does it turn into?
By altering the genes of the bacteria, essentially giving it engineered instructions, is that going to persist in the environment?
Could it cause unforeseen changes in the microbiome?

Yip said there are all sorts of other ecological questions that need to be answered before letting it loose in nature, but the research is worth pursuing.

“My hope is that this technology can be a platform for allowing you to get rid of microplastics in different types of environments. So, wastewater treatment plants being one of them and perhaps in the far future in the oceans or lakes, or in soil,” he said.