
Researchers from the University of Waterloo added DNA to several species of bacteria found in wastewater, allowing them to biodegrade polyethylene terephthalate (PET), a common plastic found in carpet, clothing and containers for food and beverages.
PET plastics take hundreds of years to degrade in the environment. Over time, they break down into microplastics, pieces of plastic less than 5 mm long, which enter the food chain. Chemicals in these plastics are associated with insulin resistance, cancer and decreased reproductive health.

The researchers use a natural process referred to as "bacterial sex," where bacteria share genetic material with each other when multiplying. It enables the introduction of a new trait into the target bacteria, giving them the ability to break down microplastics.
"As next steps, we will use modelling to understand how well the bacteria transfer the new genetic information under different environmental conditions and thus how effectively they can break down the plastics," said Dr. Brian Ingalls, a professor in the Department of Applied Mathematics. "The long-term vision is to break down microplastics in wastewater treatment plants at scale."

"We will assess the risks of using engineered, plastic-eating bacteria in the natural environment" said Aaron Yip, a PhD candidate in the Department of Chemical Engineering. "Right now, microplastic degradation in wastewater treatment plants is a safer application to target. Many of these facilities are already designed to neutralize bacteria in wastewater, which would kill any engineered bacteria prior to discharging water back into the environment."
The study, " Degradation of polyethylene terephthalate (PET) plastics by wastewater bacteria engineered via conjugation ," appears in Microbial Biotechnology.