Researchers at NC State University have been working for years on using genetically-modified bacteria to break down plastics in saltwater.
About 60% of plastic waste is either landfilled or polluting the environment due to poor recycling methods. Microplastics are now found in oceans and even the human body.
In the fall of 2020, PhD candidate at NC State, Tianyu Li, hit the ground running in her program, leading research in plastic-degrading bacteria, funded by the National Science Foundation.
Li said her team’s research has led to the first genetically engineered organism that we know of that’s capable of breaking down PET microplastics in saltwater.
“PET is polyethylene terephthalate, you can find from the water bottles, or some polyester fibers, so it’s really commonly used in our daily life.”
In order to break down PET plastics, Li said the research team incorporated naturally occurring features of two types of bacteria, one microbe known to eat PET that did not grow well in salt water, and one microbe that rapidly reproduces in saltwater.
Together, these microbes have created an organism capable of successfully breaking down PETs, but Li said the next step is using the plastics as a food source for the bacteria.
“Hopefully we are able to let this strain to completely break down the PET waste and utilize the breakdown product for cell growth.”
Associate Professor of Chemical Biomolecular Engineering at NC State, Nathan Crook said this research has been really exciting to be a part of.
“It’s been really cool because you’re trying to teach biology how to eat something that’s not biological, it’s kind of unique in nature, usually nature eats other things in nature.”
Li and Crook said they are excited to continue to improve the research they’ve done. Their engineered bacteria can break down one gram of PET plastic in about 24 years, which might seem slow, but is much faster than the hundreds of years it would normally take in nature.
“One microbe breaks down a little of the plastic and gives it enough energy to divide, and now you have two microbes able to break down that plastic, and that process can repeat over and over again.”
As time goes on, Crook said the team believes this research could be applied outside the lab to help reduce plastics in natural environments.
“Our long term vision would be something that’s actually commercially useful.”
As the researchers consider real-world applications for their work, Li said their main priority is reducing waste, but also safeguarding natural habitats, ensuring that these microbes remain contained, so they’re only helping instead of causing any harm.