Enzyme eating Plastic
An international research team headed by Prof John McGeehan, at the University of Portsmouth, has - by accident - created a mutant enzyme that breaks down PET (polyethylene terephthalate) plastic.
The new research was spurred by the discovery in 2016 of the first bacterium that had naturally evolved to eat plastic, at a waste dump in Japan. Scientists have now revealed the detailed structure of the crucial enzyme produced by the bug.
The structure of the enzyme looked very similar to one evolved by many bacteria to break down cutin, a natural polymer used as a protective coating by plants. When the team manipulated the enzyme to explore this connection, they accidentally improved its ability to eat PET - by 20% - meaning that the enzyme is not yet optimised. Making use of all the technology used in other enzyme development could make a super-fast enzyme possible.
The mutant enzyme takes a few days to start breaking down the plastic – far faster than the centuries it takes in the oceans. Plastic bottles that are recycled can only be turned into opaque fibres. The new enzyme indicates a way to recycle clear plastic bottles back into clear plastic bottles, which could slash the need to produce new plastic.