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Could Plastic-Gobbling Bacteria Save the Environment?

Japanese scientists discovered a microbe that digests one of the most common plastics

A worker sorts plastic in a recycling plant in Bangladesh. A new bacteria could make her job obsolete (Pacific Press/Corbis)
smithsonian.com

With plastics abounding throughout the environment, many scientists argue that we are living in the Plastic Age. There is so much plastic that bits of the petroleum-based material now form composite rocks called plastiglomerates. And the oceans are a veritable stew choked with 5 trillion plastic bits.

It’s a dire situation, but a few intrepid Japanese researchers potentially just made a first step toward reducing some of the 311 million tons of plastic produced annually, reports Eric Niler for Discovery News. The team spent five years combing through sludge, sediment and wastewater to collect samples contaminated with the common plastic known as PET, aka Polyethylene terephthalate, labeled with recycling code one.

It was in a sludge sample collected outside a plastic bottle recycling center in Sakai, Japan, where researchers found it—a strain of bacteria that actually gobbles up PET.

The new bacteria, named Ideonella sakaiensis 201-F6, uses two enzymes to break down the PET into much smaller compounds, explains Angus Chen at NPR. And the products, terephthalic acid and ethylene glycol are not harmful to the environment in small doses.

It seems like the perfect solution to our plastic woes.

There are problems, however. First, the process is slow. The bacteria take 6 weeks at 86 degrees Fahrenheit to gnaw away at plastic film about the size of a thumbnail, Andy Coghlan writes for New Scientist. The researchers also speculate that it may not be hardy enough to survive in landfills or other environments long enough to finish the job. The bacteria probably won’t make it in salt water either, limiting its use in reducing PET in marine environments, oceanographer Giora Proskurowski from the University of Washington tells The Christian Science Monitor.

Still, the discovery of Ideonella sakaiensis 201-F6 may be the first step in synthesizing compounds or tweaking other organisms to do the same job quicker and better. “If you can understand the genomic basis for these enzymes, is that something one could modify or harness to create more efficient PET digesting organisms?” asks Odile Madden a materials scientist and plastics expert at the Smithsonian’s Museum Conservation Institute. “Could you create organisms that digest other plastics? What would other consequences be?”

If scientists don’t come up with more plastic-gorging organisms soon, nature might just do the job for them. In fact, there might already be other plastic-loving microbes out there that we haven't identified.

"The idea that there is no organism that could break down plastic chemically and no organism that can metabolize it doesn't make sense," says Madden "If they did not already exist, and there is this carbon-rich food source available, they could certainly evolve [to fill this niche]."

Also, microorganisms reproduce much more quickly than we do, so that means they also evolve faster. "Those that can eat synthetic polymers around them efficiently are likely to be successful and proliferate." says Madden.

Proskurowski too thinks that over time more species will adapt to a life of eating old Barbie dolls and coffee makers. "The environment is evolving and you get the microbes evolving along with that as well," he says. "I’m surprised it’s taken this long. I’ve been waiting for results like this."

In the meantime, while researchers figure out the secrets of Ideonella and the rest of nature evolves to ingest the plastosphere, it’s probably best just to keep pulling those recycling bins to the curb every week.

About Jason Daley

Jason Daley is a Madison, Wisconsin-based writer specializing in natural history, science, travel, and the environment. His work has appeared in Discover, Popular Science, Outside, Men’s Journal, and other magazines.

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