Ocean Pollution Is Causing a Rise in Plastic-Eating Microbes

The world’s oceans have become synonymous with devastating plastic pollution. Just ask Aquaman. But scientists and engineers continue to come up with inventive solutions. Now, Earth’s own response to plastic pollution may serve as inspiration for a solution: microbes that can break down the stuff. And the microbes are already in hefty supply. Their population appears to be rising as plastic pollution in the ocean does.

In a new study published in the journal mBIO, which comes via Gizmodo, a team of scientists at Chalmers University in Sweden describes how it came to the conclusion that plastic-eating microbes are growing in population size alongside marine plastic pollution. The team describes how it looked at existing databases of DNA samples from soils and ocean regions around the world. They used computer modeling to look for protein sequences that would likely have the ability to break down plastic.

A beach littered with plastic, which scientists say can be digested by many types of microbes around the world.
vaidehi shah

The scientists say that one in every four organisms in the microbiomes they studied carries a protein sequence for degrading plastic. These protein sequences are enzyme homologues. That means they are similar in function and structure to enzymes. An enzyme is a substance that acts as a catalyst in living organisms and is key for digestion of food.

“Currently, very little is known about these plastic-degrading enzymes, and we did not expect to find such a large number of them across so many different microbes and environmental habitats,” first author of the study and former post-doc, Jan Zrimec said in a press release. “This is a surprising discovery that really illustrates the scale of the issue,” the researcher added.

A map of plastic-degrading enzymes across the global microbiome.
Jan Zrimec et al. / mBIO

Incredibly, the team found a correlation between the number of microbes with plastic-degrading protein sequences and amount of plastic pollution in their local environment. In the map above, the scientists have marked where they found microbes with plastic-degrading microbiomes. The larger circles not only correspond with a higher number of plastic-degrading enzymes, but also an increase in plastic pollution.

Whether or not these plastic-degrading microbes could be useful for actively clearing out plastic pollution is still, of course, unclear. But the idea of degrading plastics with microbes seems to be catching on amongst researchers. There’s certainly the scent of some biological solution to the plastic pollution problem worth pursuing in the air.