Researchers at the ETH Zurich and the Swiss Federal Institute of Aquatic Science and Technology (Eawag) have found that microorganisms can break down biodegradable polymers.
They used the biodegradable polymer PBAT, labelled with a carbon isotope, which allowed the scientists to track the polymer-derived carbon along different biodegrading pathways in soil.
It found that the carbon from the PBAT incorporated into the biomass of the microorganisms and colonized the polymer surface.
The researchers are the first to show where the carbon of a polymer ends up and that a plastic material is effectively biodegrading in soils.
European Bioplastics managing director Hasso von Pogrell said: “With this study, two concerns that are constantly being raised about biodegradable plastics have been rebutted – the doubt that microorganisms fully metabolise certified biodegradable plastics and the concern that the oil-based part of the polymer will not biodegrade completely.”
He added: “The results of this study will surely enable municipalities and waste managers across EU Member States to acknowledge the benefits and the functionality of certified compostable plastic bio-waste bags for a separate collection of organic waste as well as in an agricultural context the alternative of soil biodegradable mulch films.”
The tested PBAT polymer is a fossil-based, biodegradable polymer which is used for the production of biodegradable, certified compostable bio-waste bags and soil certified mulch films, said European Bioplastics.