Researchers have accidentally created a plastic-eating enzyme

Credits: Pexels / mali maeder

A laboratory “accident” turned into a mutant enzyme which devours plastic. In studying the bacteria Ideonella sakaiensis, which feeds exclusively on polyethylene terephthalate, American and British researchers by chance created an even more effective enzyme. 

Scientists accidentally created an enzyme which eats plastic – notably the type of plastic used for making bottles of soda, which generally takes hundreds of years to decompose. In a study published on Monday the 16th April in the Proceedings of the National Academy of Sciences of the United States of America (PNAS), the scientists explain that they in fact created this new enzyme “by accident”. This is excellent news, particularly at a time when plastic waste is piling up.

It all started when the researchers were examining the crystalline structure of a recently discovered enzyme called PETase in more detail. This is an enzyme that naturally evolved and was known to decompose and digest plastic made from polyethylene terephthalate. The enzyme ended up mutating by accident, turning into a new type of enzyme which digests plastic more effectively than the original. The improvement is minimal, but it provides a glimpse of the possibility of refining plastic-eating enzymes in order to hugely increase their appetite for polyethylene terephthalate.

“Luck often plays an important role in fundamental scientific research and our discovery is no exception”, explains John McGeehan, a professor in the school of biological sciences in Portsmouth (UK). Although the improvement is modest, this unexpected discovery suggests that there is scope for improving these enzymes, and we are coming closer to a recycling solution for the constantly growing mountain of discarded plastic.

At this stage, the study does not specify how this enzyme could be used on a larger scale than in the laboratory, nor what would happen if these enzymes were multiplied in nature. Enzyme based recycling could however represent a viable solution for dealing with ever increasing amounts plastic waste. According to Live Science, humans have already littered the planet with around 9 billion tons of plastic, half of which has been produced since 2004.