Researchers from the Swiss Federal Institute WSL have discovered microbes from the Alps and the Arctic that can break down plastic without the need for high temperatures. They published the corresponding results in the journal Frontiers in Microbiology, writes Engadget.
According to scientists, cold-adapted bacteria and fungi from polar regions and the Swiss Alps digest most of the plastics they study. At the same time, they need only low and medium temperatures. The latter is crucial, as micro-organisms that feed on plastic usually require high temperatures.
“Several microorganisms that can do this have already been found, but when their enzymes that make this possible are applied at an industrial scale, they typically only work at temperatures above [30 degrees Celsius / 86 degrees Fahrenheit],” the researchers explained. “The heating required means that industrial applications remain costly to date, and aren’t carbon-neutral.”
Unfortunately, none of the microorganisms tested were able to degrade non-degradable polyethylene (PE), which is commonly used in consumer products and packaging. But 56% of the strains tested degraded biodegradable polyester-polyurethane (PUR) at 15 degrees Celsius. Others digested biodegradable mixtures of polybutylene adipate terephthalate (PBAT) and polylactic acid (PLA). The two most successful strains turned out to be fungi from the genera Neodevriesia and Lachnellula – they decomposed all tested plastics, except for PE.
“Microbes have been shown to produce a wide variety of polymer-degrading enzymes involved in the break-down of plant cell walls. In particular, plant-pathogenic fungi are often reported to biodegrade polyesters, because of their ability to produce cutinases which target plastic polymers due [to] their resemblance to the plant polymer cutin,” said co-author Dr. Beat Frey.
Researchers see great prospects in the research results, although they warn of possible obstacles.
“The next big challenge will be to identify the plastic-degrading enzymes produced by the microbial strains and to optimize the process to obtain large amounts of proteins,” said Frey. “In addition, further modification of the enzymes might be needed to optimize properties such as protein stability.”
It was previously reported that marine animal species that usually inhabit coastal areas, build “houses” from plastic waste and survive in them in the open sea. Because plastic waste is extremely resilient, it provides open access to new spaces for species that previously could not colonize them.