Microbes in cow stomachs can break down plastic

Plastic is notoriously hard to break down, but researchers in Austria have found that bacteria from a cow's rumen – one of the four compartments of its stomach – can digest certain types of the ubiquitous material, representing a sustainable way to reduce plastic litter.

The scientists suspected such bacteria might be useful since cow diets already contain natural plant polyesters. In other words, these microorganisms can already break down similar materials, so the study authors thought they might be able to break down plastics as well.

Doris Ribitsch, of the University of Natural Resources and Life Sciences in Vienna, and her colleagues looked at three kinds of polyesters. One, polyethylene terephthalate, commonly known as PET, is a synthetic polymer commonly used in textiles and packaging. The other two consisted of a biodegradable plastic often used in compostable plastic bags (polybutylene adipate terephthalate, PBAT), and a biobased material (Polyethylene furanoate, PEF) made from renewable resources.

They obtained rumen liquid from a slaughterhouse in Austria to get the microorganisms they were testing. They then incubated that liquid with the three types of plastics they were testing (which were tested in both powder and film form) in order to understand how effectively the plastic would break down.

According to their results, which were recently published in Frontiers in Bioengineering and Biotechnology, all three plastics could be broken down by the microorganisms from cow stomachs, with the plastic powders breaking down quicker than plastic film.