Microbes that can eat plastic at low temperatures, making them more cost-effective than current ones, have been found in the Alps.

Several microorganisms capable of destroying plastic polymers have already been discovered. As a result, businesses have latched onto bioengineering the enzymes found in various bacteria and fungi as a means to tackle plastic pollution.

But the industry has been limited by the need for heating since already-discovered ones require artificially high temperatures to work, making the process costly and not carbon neutral.

Now, the Swiss Federal Institute WSL found the most effective performers were two fungi in the genera Neodevriesia and Lachnellulam, which were novel and that worked at just 15 degrees Celsius, or 60 degrees Fahrenheit.

They are capable of digesting biodegradable polyester-polyurethane (PUR), and two commercially available biodegradable mixtures of polybutylene adipate terephthalate (PBAT) and polylactic acid (PLA.)

But the study went far further, finding a total of nine fungi and eight bacteria species from multiple genera that were able to digest PUR, and a total of 14 fungi and three bacteria managed to eat mixtures of PBAT and PLA.

PUR is most commonly used in artificial textiles, while PBAT is used quite widely in industries for packaging, and PLA is found in biomedical applications like drug delivery products and sutures.

"Here we show that novel microbial taxa obtained from the ‘plastisphere' of alpine and arctic soils were able to break down biodegradable plastics at 15°C," said first author Dr. Joel Rüthi, from WLS. "These organisms could help to reduce the costs and environmental burden of an enzymatic recycling process for plastic."

"It was very surprising to us that we found that a large fraction of the tested strains was able to degrade at least one of the tested plastics."

During the hunt for a microbe capable of digesting in the cold, the team studied 19 strains of bacteria and 15 fungi growing on plastic that had been left behind or intentionally buried in Greenland, Svalbard, and Switzerland.

In Switzerland, waste was picked from the summit of Muot da Barba Peider from the valley Val Lavirun, both in the Graubünden region.

Scientists let isolated microbes grow as single-strain cultures in a dark laboratory. At 15 degrees Celsius, molecular techniques were used to identify them.

In total 59% of strains, including 11 fungi and eight bacteria, could digest PUR at 15 degrees in the study published in the journal Frontiers in Microbiology.

"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 co-author Dr. Beat Frey, also at WSL. "In addition, further modification of the enzymes might be needed to optimize properties such as protein stability."

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