How to reduce plastic pollution? Any solution could come in handy, even the most improbable. Find, grow and bioengineer organisms capable of digesting plastic it could be one of them. WSL scientists have found microbes in the Alps that can do this even at low temperatures.
In the past several microorganisms capable of doing this had already been found but, to make this possible on an industrial scale, the enzymes responsible for the process generally only work at temperatures above 30°C.
A process and a heating such that it implies the use of expensive industrial applications and certainly not with zero emissions. The only possible solution would therefore be to find and employ cold-adapted specialized microbes whose enzymes work at much lower temperatures than usual.
And that’s exactly what I scientists discoveredSwiss Federal Institute WSLstudying the microbiological populations at high altitudes in the Alps and in the polar regionsthe results of which were recently published on the pages of Frontiers in Microbiology.
Dr. Joel Rüthi, first author of the study, said: “Thanks to our work we can demonstrate that the new microbial taxonomic data obtained from the ‘plastisphere’ of alpine and arctic soils have been able to break down biodegradable plastic already at 15°C. These organisms could help reduce the cost and environmental burden of an enzymatic plastic recycling process.”.
The scientists they sampled 19 strains of bacteria and 15 of fungi which had grown on free plastic or intentionally buried (maintained on purpose in the ground for a year) in Greenland, Svalbard and Switzerland, precisely on the summit of Muot da Barba Peider (2,979 m) and in the Val Lavirun valley, both in the canton of Grisons.
The experts then let the isolated microbes grow in the laboratory, in dark conditions and at 15°, as single-strain cultures, using molecular techniques to identify them. The results therefore showed that the bacterial strains belonged to 13 genera of the phyla Actinobacteria and Proteobacteriaand fungi to 10 genera of the phyla Ascomycota and Mucoromycota.
19 (56%) of the strains, including 11 fungi and eight bacteria, they were able to digest biodegradable polyester-polyurethane (PUR) at 15°C, while 14 fungi and three bacteria were able to digest the plastic mixtures of polybutylene adipate terephthalate (PBAT) Ed polylactic acid (PLA).
Also from the analyzes carried out through nuclear magnetic resonance (NMR) and a test based on fluorescence they confirmed that these strains had been capable of breaking the polymers of PBAT and PLA into much smaller molecules.
“It was very surprising for us to find that a large fraction of the strains tested were capable of degrading at least one of the plastics tested”enthused Dr. Rüthi.
Unfortunately, the plastic problem is now very serious, with microplastics found in the most remote places on Earth, also considering the fact that we ingest a monstrous amount of it every year.
