European Bioplastics: Swiss research confirms environmental benefits of bioplastic packaging

17 Aug 2018 --- European Bioplastics believe that EU Member States will now be able to comprehensively acknowledge the benefits and the functionality of certified compostable plastic after a successful demonstration of the environmental benefits of the material. Researchers at ETH Zurich and the Swiss Federal Institute of Aquatic Science and Technology (Eawag) succeeded in an interdisciplinary study to demonstrate that soil microorganisms metabolically utilized the carbon in the PBAT polymer both for energy production and also to build up microbial biomass.

Hasso von Pogrell, Managing Director of European Bioplastics tells PackagingInsights: “Even though the results only confirm what we have stated all along, i.e. that biodegradable plastics certified to be compostable in industrial composting facilities according to EN 13432 or to biodegrade in soil according to EN 17033 eventually biodegrade completely, the fact that this research actually shows what happens inside the bacteria is, indeed, a major breakthrough.”

“This clarifies that nothing remains after biodegradation besides water, CO2 and biomass,” says Pogrell. “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.”

“Whether or not this will have a significant impact on the packaging market, however, remains to be seen, given the fact that the doubts as to the true biodegradability of biodegradable plastics is only one of many hurdles to overcome when trying to push the market for biodegradable plastics.”

“Differing laws in the individual European Member States as to whether or not certified compostable packaging is allowed in the biowaste bin is just another example of preventing their market uptake. Currently, only in Italy certified compostable packaging is allowed to be discarded in the biowaste bin. Other countries, e.g. Germany, only allows for biowaste bags, explicitly produced for this purpose. The probably still remaining negative attitude towards biodegradability from NGOs is yet another hurdle to overcome.”

“Of course we hope that this study will help to abolish some of the hurdles mentioned above, but a change in attitude towards bioplastics will certainly not come overnight. In the long run, however, I’m convinced that studies like this one will help to pave the way,” Pogrell adds.

The researchers used the biodegradable polymer PBAT (Polybutylenadipatterephthalat) labeled with a carbon isotope. This isotope label enabled the scientists to track the polymer-derived carbon along different biodegradation pathways in soil. It showed that the carbon from PBAT was not only converted into carbon dioxide (CO2) as a result of microbial respiration but also incorporated into the biomass of microorganisms colonizing the polymer surface.

The researchers are the first to successfully demonstrate where the carbon of a polymer ends up and that a plastic material is effectively biodegrading in soils.

The tested PBAT polymer is a fossil-based, biodegradable polymer, which is used amongst others for the production of biodegradable, certified compostable bio-waste bags (according to EN 13432) or biodegradable in soil certified mulch films (according to EN 17033).

Bioplastics expert Neil Farmer gives his views to PackagingInsights: “I'm sure the research will be welcomed, particularly as it shows a plastic material is effectively biodegrading in soils. Aliphatic polyesters and aliphatic-aromatic co-polyesters, which include PBAT, are readily biodegradable and compostable.”

“However, the question about the levels of biodegradability would still be a concern. I have seen information that indicates that PBAT has good mechanical and thermal properties when the proportion of terephthalic acid co-monomer is greater than 35 percent, but its biodegradability decreases at levels of 55 percent or higher,” he says.

“These polyesters have properties similar to polyolefins, but are relatively expensive and are mostly used in combination with other polymers such as PLA and starch as components of biodegradable plastic formulations, particularly for films,” Farmer adds.

Rising demand for more environmentally-responsible consumer products is driving innovation in biodegradable and compostable packaging solutions. Public concern for the environmental impact of everyday packaging materials – particularly plastics – has intensified, creating market opportunities for creative, forward-thinking and sometimes entirely unusual biodegradable/compostable packaging.

While the commercialization of innovative biodegradable/compostable packaging may be a challenge in itself, the popularity of this packaging type is on the rise. Innova Market Insights reports a 40 percent increase in new food and beverage products packaged in bio-based/biodegradable material (CAGR 2013-2017). Meanwhile, a survey found that more than 35 percent of German consumers, 25 percent of UK consumers and more than 25 percent of US consumers consider bio-based and/or biodegradable/compostable packaging important in food and beverage choice (Innova Market Insights, 2015).

Read more about innovations in biodegradable packaging here.

By Joshua Poole