/https://tf-cmsv2-smithsonianmag-media.s3.amazonaws.com/filer_public/17/89/1789c120-8384-484a-b365-4ac257bee078/gettyimages-1223473775.jpg?resize=780,470 "Discover Microbes That Could Revolutionize Plastic Recycling | Smart News")
World record holder Turkish freediver Sahika Ercumen swims amidst plastic waste on June 27, 2020 to raise awareness about plastic pollution. Sebnem Coskun/Anadolu Agency via Getty Images
To tackle the growing global problem of plastics, humans may need to use every tool in the arsenal, even microscopic bacteria and fungi. High in the Swiss Alps and in the Arctic, scientists have discovered microbes that can digest plastics, especially without the need to apply excessive heat. Their findings, published this month in the journal Frontiers in Microbiology, may one day improve plastic recycling.
From the Great Pacific Garbage Patch to the tiny microplastics that invade our drinking water, tea, fish and blood, it’s no secret that plastic pollution is a major global problem. Since its production exploded during and after World War II, humans have created more than 9.1 billion tons of plastic and researchers estimate that less than a tenth of the resulting waste has been recycled.
To make matters worse, the most common recycling option – when plastic is washed, processed and turned into new products – does not actually reduce waste: recycled materials are often of lower quality and can still end up later in a landfill.
In reality, this strategy “is not recycling,” Alain Marty, scientific director of Carbios, a French company developing recycling alternatives, told Undark’s Ula Chrobak last year. “At the end… you have exactly the same amount of plastic waste.”
So researchers are looking for solutions to the problem of plastics that go beyond conventional recycling – and one process they’ve experimented with is breaking down plastics using microorganisms. But that’s still not entirely practical — typically, the known microbes that digest plastic can only do so at hot temperatures above 85 degrees Fahrenheit. When done on an industrial scale, the amount of energy needed to generate so much heat makes the process emit more carbon and cost more.
But enzymes from microorganisms found in the Arctic and the Swiss Alps can work in colder temperatures: they were able to break down biodegradable plastics at 59 degrees Fahrenheit, opening the doors to a more efficient system.
“These organisms could help reduce the costs and environmental burden of an enzymatic plastic recycling process,” says co-author Joel Rüthi, currently a guest researcher at the Federal Institute for Forest, Snow and Snow Research. landscape (WSL). statement.
Colorful plastic bottles ready to be recycled in Pontedera, Italy, some of which have been salvaged by fishermen. Laura Lezza via Getty Images
In the new study, Rüthi and her colleagues sampled 19 strains of bacteria and 15 types of fungi in Greenland, Switzerland and Norway’s Svalbard archipelago. The microbes grew on loose pieces of plastic or those that had been intentionally buried in the ground for a year.
Of the total 34 types of microbes examined, 19 were able to break down a form of plastic called polyester-polyurethane, and 17 were able to break down two types of biodegradable plastic blends. But none could digest polyethylene, the most commonly produced plastic, which is used in food containers and plastic bags.
The study described a “simple” way to isolate these bacteria and fungi, which occur naturally in nature, said Ludmilla Aristilde, a molecular biochemist at Northwestern University who was not involved in the study, at the Smithsonian magazine.
“Harnessing natural microbes can provide a ‘head start'” when it comes to devising a bio-recycling strategy or using living organisms to break down plastic waste, says Aristilde.
With further study, the authors hope to determine the optimum temperature for these enzymes to work. They also hope to identify the specific mechanisms of microbes to break down plastics.
“The next big challenge will be to identify plastic-degrading enzymes produced by microbial strains and optimize the process to obtain large amounts of protein,” said co-author Beat Frey, senior scientist and group leader at WSL. statement.
Last year, scientists reported other creative ways to break down plastics with enzymes, such as those in the saliva of waxworms and in the guts of beetle larvae.
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Filed Under: Earth Sciences, Engineering, Environment, Innovations, Microbes, Bacteria, Viruses, Plastic, Pollution
