Thanks to a genetically engineered enzyme, a bug that eats plastic bottles developed a much bigger appetite for our rubbish. It is a hopeful sign
Evolution never sleeps. Before 1970 there can have been no significant bacteria that ate plastic, because there was not enough of that plastic in the world to sustain a population. But in 2016 a group of Japanese scientists discovered a new species, Ideonella sakaiensis, in the samples they were sifting from a bottle-recycling plant, that was able to attack and eat PET, the plastic used in most bottles, almost all of which ends up in landfill or dumped at sea, where it may last for centuries. Everything that rots in nature does so because it is being eaten by bacteria. Most plastics – among them PET – were considered totally impervious to bacterial attack, making them almost indestructible unless burned or crushed. So a bacterium that can consume even one kind of plastic could become a desperately needed ally in the struggle to stop the oceans being choked with plastic waste.
What has captured the imagination of the world is that a subsequent group of scientists, who were trying to understand on a molecular level how I sakaiensis breaks down and digests plastic bottles, found the enzymes that it uses and made a slightly different version of one to see what would happen. The new enzyme is much more efficient than the version found in nature, and works on more kinds of plastic. This kind of molecular tweaking of substances, already found in nature, is at the root of another recent scientific breakthrough, the Crispr-Cas9 technique for genetic engineering. It offers some hope that we can use technology to moderate and even to some extent to reverse the impacts that earlier technologies, such as those that make it easy to manufacture billions of tons of plastic, have had on the world around us.