Scientists have created a mutant enzyme that breaks down plastic drinks bottles it is called PETase – by accident.
PETase was first detected in the bacterium Ideonella sakaiensis, which used the enzyme to munch on plastic in the soil of a PET bottle-recycling facility in Japan. Scientists have now revealed the detailed structure of the crucial enzyme produced by the bug.
The international team then tweaked the enzyme to see how it had evolved, but tests showed they had inadvertently made the molecule even better at breaking down the PET (polyethylene terephthalate) plastic used for soft drink bottles.
The mutant enzyme takes only a few days to start breaking down the plastic – far faster than the centuries it takes in the oceans. The researchers are optimistic this can be accelerated even further and can be made into a viable large-scale process.
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. But when the team manipulated the enzyme to explore this connection, they accidentally improved its ability to eat PET.
A patent has been filed on the specific mutant enzyme by the Portsmouth researchers and those from the US National Renewable Energy Laboratory in Colorado.
This enzyme can turn the plastic back into its original components, so it can be literally recycled back to plastic. This fundamentally means it will reduce the amount of plastic in the environment.
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.
Reference- The Guardian, Live Science, National Geographic, Wikipedia