In 2016 a bacterium that had naturally evolved to eat PET (polyethylene terephthalate) plastic was discovered at a dump in Japan. Scientists who were studying the bacterium say that when they tweaked the bacterium's plastic-eating enzyme to better understand how it evolved, they accidentally created an even more voracious plastic-eating enzyme.
From The Guardian:
"What actually turned out was we improved the enzyme, which was a bit of a shock," said Prof John McGeehan, at the University of Portsmouth, UK, who led the research. "It's great and a real finding."
The mutant enzyme takes a few days to start breaking down the plastic – far faster than the centuries it takes in the oceans. But the researchers are optimistic this can be speeded up even further and become a viable large-scale process.
"What we are hoping to do is use this enzyme to turn this plastic back into its original components, so we can literally recycle it back to plastic," said McGeehan. "It means we won't need to dig up any more oil and, fundamentally, it should reduce the amount of plastic in the environment."