Birmensdorf, Switzerland – Although microorganisms have been discovered that can degrade plastics, the enzymes responsible generally require elevated temperatures to work, increasing the amount of energy required for the process and reducing their potential as a practical method for waste management. Now, scientists at the Swiss Federal Institute WSL have discovered bacteria in the Alps and the Arctic that can break down plastics at 15°C.
The team, led by Joel Rüthi, looked at 19 strains of bacteria and 15 fungi that were growing on plastic in Greenland, Svalbard and Switzerland. The isolated microbes were grown at 15°C in the dark as single-strain cultures, and identified.
These strains were then screened for the ability to digest four different plastics, including Covestro’s Impranil DLN-SD, an anionic aliphatic polyester polyurethane used as a textile coating. More than half the strains – 11 fungi and eight bacteria – successfully digested the Impranil when incubated at 15°C.
Next steps for the researchers include identifying the enzymes responsible for the plastic degradation, and engineering the microbes to produce larger amounts of these enzymes. It may also be possible to optimise the enzymes to improve stability, for example.
“We showed that novel microbial taxa obtained from the ‘plastisphere’ of alpine and arctic soils were able to break down biodegradable plastics at 15°C,” Rüthi said. “These organisms could help to reduce the costs and environmental burden of an enzymatic recycling process for plastic.”
The work has been published in the journal Frontiers in Microbiology.
