In a press release published on August 16, 2018, the industry association European Bioplastics (EUBP) informed about a recent scientific study showing that “soil microorganisms metabolically utilized the carbon in the PBAT polymer both for energy production and also to build up microbial biomass.” Researchers from ETH Zurich, Switzerland, the University of Vienna, Austria, and the Swiss Federal Institute of Aquatic Science and Technology (Eawag), used the fossil-based, biodegradable polymer polybutylene adipate terephthalate (PBAT) and “successfully demonstrate[d] where the carbon of a polymer ends up and that a plastic material is effectively biodegrading in soils,” EUBP reported. The study was published on July 25, 2018, in the peer-reviewed journal Science Advances.
PBAT is used for products such as compostable bio-waste bags and soil-biodegradable mulch films, EUBP explained. Hasso von Pogrell, managing director of EUBP, stated: “This clarifies that nothing remains after biodegradation besides water, CO2 and biomass.” He further added: “With this study, two concerns that are constantly being raised about biodegradable plastics have been rebutted – the doubt that microorganisms fully metabolize certified biodegradable plastics and the concern that the oil-based part of the polymer will not biodegrade completely.”
The researchers remained more cautious about their results. “Unfortunately, there is no reason to cheer as of yet: We’re still far from resolving the global environmental problem of plastic pollution,” stated Michael Sander, co-author of the study, in the press release of ETH Zurich. “As we have demonstrated, there is hope for our soils in the form of biodegradable polymers,” he added. However, “[t]he results from soils should . . . not be directly transferred to other natural environments,” he stressed, explaining that “[f]or instance, biodegradation of polymers in seawater might be considerably slower, because the conditions there are different and so are the microbial communities.”
European Bioplastics (August 16, 2018). “Microbes fully metabolize biodegradable plastics.”
Peter Rüegg (July 25, 2018). “Soil bugs munch on plastics.” ETH Zurich News
Zumstein, M. T., et al. (2018). “Biodegradation of synthetic polymers in soils: Tracking carbon into CO2 and microbial biomass.” Science Advances (published online July 25, 2018).