SoylentNews

upstart writes:

Scientists from Switzerland have identified 19 novel strains of cold-adapted specialist bacteria and fungi from the Alps and the Arctic region that can digest biodegradable plastics:

Finding, cultivating, and bioengineering organisms that can digest plastic not only aids in the removal of pollution, but is now also big business. 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°C. The heating required means that industrial applications remain costly to date, and aren't carbon-neutral. But there is a possible solution to this problem: finding specialist cold-adapted microbes whose enzymes work at lower temperatures.

[...] "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, currently a guest scientist at WSL. "These organisms could help to reduce the costs and environmental burden of an enzymatic recycling process for plastic."

[...] None of the strains were able to digest PE [non-biodegradable polyethylene], even after 126 days of incubation on these plastics. But 19 (56%) of strains, including 11 fungi and eight bacteria, were able to digest PUR [biodegradable polyester-polyurethane] at 15°C, while 14 fungi and three bacteria were able to digest the plastic mixtures of PBAT [biodegradable polybutylene adipate terephthalate] and PLA [biodegradable polylactic acid]. Nuclear Magnetic Resonance (NMR) and a fluorescence-based assay confirmed that these strains were able to chop up the PBAT and PLA polymers into smaller molecules.

"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," said Rüthi.

The best performers were two uncharacterized fungal species in the genera Neodevriesia and Lachnellula: these were able to digest all of the tested plastics except PE. The results also showed that the ability to digest plastic depended on the culture medium for most strains, with each strain reacting differently to each of four media tested.

Original Submission