Government scientists have made progress in recycling plastics that end up in landfills

ABSTRACT breaks down scientific research, future technologies, new discoveries and breakthroughs.

It’s plastic everywhere. According to the US Department of Energy’s National Renewable Laboratory (NREL), in the United States, only 5 percent the plastic used is actually recycled. This is great because plastics are not chemically identical, making it more difficult and expensive to separate individual polymers. These mixed plastics often end up in landfills and the environment.

Now, a new one published research in the year science on Thursday outlines a new process that will allow us to recycle these plastics that end up as waste that will take hundreds of years to degrade.

The study, led by NREL researchers as part of the Bio-Optimized Technologies to Keep Out of thermoplastics and the Environment (BOTTLE) Consortium, presents a hybrid approach to recycling that uses chemical and biological processes to reuse plastics. .

“There are very few ways to deal with mixed plastics when it comes to recycling,” explains Gregg Beckham, NERL’s senior research associate and project leader. “We wanted to be able to turn mixed plastic waste, polymers or plastic waste into a single product without sorting it.”

As the paper explains, mixed plastics waste “represents an abundant and largely untapped raw material for the production of valuable products.”

This study used three common plastics: Polystyrene Polyethylene, Terephthalate and High Density Polyethylene. All three are abundant components of post-consumer plastic waste and were successfully oxidized and converted.

First, the team used metal-catalyzed oxidation to break down plastics into smaller molecules suitable for biological conversion. These molecules can be described as “smaller, more biologically friendly chemical building blocks,” says lead author and Oregon State University researcher Lucas Ellis. a press release. This is necessary for the next step in the process: feeding the bacteria.

They then used a biologically engineered soil microbe Pseudomonas putida to try to turn the oxygenated building blocks into a more useful product. The bacteria were able to “funnel” (aka convert) the compounds into two different products: biopolymers used in biodegradable bioplastics and another compound that can be used in nylon production.

Although the study only looked at three plastics, in the future the researchers hope to focus on other types of plastics found in consumer waste, and even create different products.

The researchers see this study as a proof-of-concept, demonstrating that chemical oxidation and biological funneling can work together to recycle plastics, improve product value, and make recycling more efficient.

“Experimentally, it works, but this is not ready to scale tomorrow,” Beckham said. “The proven concept is really exciting, but there’s more engineering work to be done to make this idea and process concept economically viable at scale and better than business as usual.”