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Microbes fished from the stomachs of cows can gobble up certain kinds of plastic, including the polyethylene terephthalate (PET) used in soda bottles, food packaging and synthetic fabrics.

Scientists uncovered these microbes in liquid that was drawn from the rumen, the largest compartment of a ruminant's stomach; ruminants include hooved animals like cattle and sheep, which rely on microorganisms to help break down their diet of coarse vegetation. The rumen acts as an incubator for these microbes, which either digest or ferment foods consumed by a cow or other ruminant, according to the University of Minnesota. The researchers suspected that some microbes lurking in a cow's rumen should be capable of digesting polyesters, substances whose component molecules are linked by so-called ester groups.

That's because, due to their herbivorous diets, cows consume a natural polyester produced by plants, called cutin. As a synthetic polyester, PET shares a similar chemical structure to this natural substance. Cutin makes up most of the cuticle, or the waxy outer layer of plant cell walls, and it can be found in abundance in the peels of tomatoes and apples, for example, said corresponding author Doris Ribitsch, a senior scientist at the University of Natural Resources and Life Sciences in Vienna.

"When fungi or bacteria want to penetrate such fruits, they are producing enzymes that are able to cleave this cutin," or split the chemical bonds within the substance, Ribitsch told Live Science. Specifically, a class of enzymes called cutinases can hydrolyze cutin, meaning they jump-start a chemical reaction in which water molecules break the substance into bits.