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plastic water bottle recycling
Photo by tanvi sharma on Unsplash
blue labeled plastic bottles

Plastics are one of the biggest and most problematic contributors to pollution. Millions of tons of plastic end up in the ocean each year. According to environmentalist Ellen MacArthur, if plastic production and pollution continue at the current rate, by 2050 the ocean will contain more plastic by weight than it does fish. Part of what makes plastic so problematic is that it's not biodegradable and can take up to hundreds of years to break down in nature. Most plastic ends up either in landfills or in the ocean. It is estimated that less than 10% of plastic is actually recycled. In the decades since plastic usage has become widespread, it's proven unruly and unsustainable. However, in the last few years scientists have discovered an enzyme that has the potential to transform our relationship with plastic forever.

Polyethylene terephthalate, or PET plastic, has been one of the dominant types of plastic since it was patented in 1941. Almost all of the single-serving and 2-liter beverages in the US are in plastic bottles made up of PET plastic. In 2016, Japenese researchers discovered a bacterium, Ideonella sakaiensis, growing on PET plastic sediment in a waste recycling center. Upon further examination researchers discovered that the bacterium produced two enzymes, PETase and MHETase which broke down PET plastic into TPA and Ethylene glycol—the building blocks for making new PET plastic. These enzymes broke down the plastic in a matter of days, rather than the hundreds of years PET naturally takes to degrade. The enzymes have also shown the ability to break down PEF plastic, a bio-based substitute to PET which, like PET, is not otherwise biodegradable.

In addition to its potential to fight pollution, part of what makes this discovery so extraordinary is that it's a natural solution to an unnatural, or manmade, problem—consuming a material that was only invented mere decades ago. In the years since the discovery, researchers have even improved on the natural form of Ideonella sakaiensis. While altering the proteins to understand how they worked, scientists accidentally made the enzymes even more efficient, by about 20%. These enzymes are still being studied and experimented with, and aren't yet prepared to fully solve the plastic problem—they don't break down all types of plastic, for example. There is, however, reason to be optimistic. As John McGeehan, the director of the Center for Enzyme Innovation stated to CNN, "this unanticipated discovery suggests that there is room to further improve these enzymes, moving us closer to a recycling solution for the ever-growing mountain of discarded plastics," said McGeehan."

Watch this video to learn more about ideonella sakaiensis:

Ending Plastic Pollution with Designer Bacteria www.youtube.com



























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