Scientists Accidentally Create a Mutant Enzyme That Eats Plastic Waste

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The plastic-eating microbe, Ideonella sakaiensis, was first discovered in 2016 when it was munching on discarded plastic bottles at a plastics recycling plant in Japan.

Since then, scientists have been closely examining how this Japanese bug breaks down plastic. In the process, scientists have accidentally created a new mutant enzyme that actually outperforms the natural bacteria that learned to eat the plastic that dominated its natural habitat.

A little more research together with some clever tweaks could give us the answer to the colossal plastic problem that is faced by us humans today. While the new discovery is no exception to the act of serendipity, this one plays a significant role in offering a perfect solution to the plastic problem.

The discovery was made by the team of structural biologist McGeehan from UK’s University of Portsmouth whose members also include researchers from US Department of Energy’s National Renewable Energy Laboratory – NREL. The members were closely monitoring the crystal structure of the enzyme PETase – the enzyme that helps I. sakaiensis in breaking down the polyethylene terephthalate (or PET) when they stumbled on the new mutant enzyme.

Even while the microbe indeed eats plastic, it is rather slow at munching. However, the bacteria can break down the plastic in just a matter of few days compared to centuries taken to break down plastic naturally. But compared to the vast problem of plastics getting accumulated on land and water in huge amounts on a daily basis, there is a need to quicken the process in speeding our efforts to get rid of it.

So the new discovery of the ‘accidental; enzyme really comes as a boon to scientists. When they picked up some PET bottles from landfills and oceans and subjected the same to be ‘eaten’ by the bacteria, the scientists noticed that I. sakaiensis could degrade a PET in just 96 hours.

They also examined the efficiency of the bacteria in degrading the PET and created a high resolution 3D model of the enzyme by using X-rays and could clearly see the microbe’s active part that was effective at breaking down the plastic. Eventually, they also learned by chance how the plastic-breaking mechanism of the enzyme can be improved. Scientists are now of the opinion that they can easily optimize the enzyme’s plastic breaking mechanism and believe that this will also help them in finding new ways to recycle other materials too.