Bacteria found in the rumen of a cow could help to break down plastics, an Austrian study has found.

Cows’ diets already contain natural plant polyesters, or cutin, which can be broken down by enzymes produced by bacteria in the rumen.

The study, recently published in Frontiers in Bioengineering and Biotechnology found that these enzymes could be used to degrade synthetic plastics.

In Europe, widespread consumption of plastic has led to the accumulation of 25.8 million tonnes of waste in the environment and seas, with polyesters accounting for approximately 15% of this, according to the study.

New ways to combat this environmental issue are required.

Research on cow stomach liquid

So, researchers from the University of Natural Resources and Life Sciences (BOKU) in Vienna, the Austrian Center of Industrial Biotechnology and the University of Innsbruck set out to test the ability of the rumen to degrade three synthetic polyesters – polyethylene terephthalate (PET), polybutylene adipate-co-terephthalate (PBAT) and polyethylene furanoate (PEF).

PET is the most important synthetic polyester that is used in textiles, packaging and plastic bottles; PBAT is a biodegradable plastic that is used in compostable bags; and PEF is made from renewable resources.

Fresh rumen liquid – from an Alpine cow – was obtained from a slaughterhouse in Austria and the researchers tested the liquid with the three aforementioned polyesters (in both powder and plastic form).

They discovered that the rumen liquid was effective in degrading all three polyesters. The powders broke down quicker than the plastics.

Scientists believe that it is the combination of enzymes present in the cow’s rumen that contributed to its effectiveness when compared with previous studies that might have focused on just one particular enzyme.

The researchers said that future studies should focus on “identification and cultivation of the microbes and enzymes” involved in this breakdown of polyesters.