Some Bacteria Have Evolved the Ability to Degrade Plastic

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P.rubber bands are easy to throw away but difficult to get rid of. Unlike biodegradable materials, bacteria and fungi have not evolved the ability to break them down, leaving plastic waste to languish for decades, eventually ending up in our oceans. And everywhere else. Now that could change.

According to a new study published in The ISME magazinemarine bacteria are beginning to develop enzymes capable of breaking down polyethylene terephthalate (PET), one of the most common plastics. Researchers from Saudi and Spanish institutions used artificial intelligence and genetic information from large numbers of ocean bacteria to identify a pattern of genetic sequence they call the M5 motif that encodes functional PETases, the enzymes that break down PET plastics.

“The M5 motif acts like a fingerprint that tells us when a PETase is likely to be functional, capable of breaking down PET plastic,” team co-leader Carlos Duarte said in a statement. “His discovery helps us understand how these enzymes evolved from other hydrocarbon-degrading enzymes.”

Duarte and his co-authors confirmed that the M5 motif is what distinguishes real PETases from lookalikes in laboratory experiments. The M5 pattern was present in nearly 80% of the water samples tested, indicating that the potential for bacteria to develop the ability to feed on plastics is widespread. They reported that bacteria making functional PETases were found between about 3,200 and 6,500 feet deep and on the ocean surface, in places heavily polluted by plastic.

Read more: “Can humanity stem the plastic tide? »

This is good news. According to the study, more than 150 million tons of plastic waste have ended up in the oceans since 1950, so there are plenty of potential resources for enterprising bacteria that have the ability to break it down. Meanwhile, the authors say this discovery could contribute to efforts to create synthetic PETases for recycling.

But the plastic crisis has many facets. The evolution of plastic-degrading microbes is unlikely to occur at a rate capable of keeping up with humanity’s production and consumption of plastic.

A report released earlier this year, by an international team of health researchers, economists and others, estimates that plastic-related health problems cost the world $1.5 trillion a year. “First and foremost, I would like to see some sort of capping or limiting of global production of new plastic,” said Philip Landrigan, lead author of this report and director of Boston College’s Program for Global Public Health and the Common Good and its Global Observatory on Planetary Health. Nautilus in August. “Even if we stopped production completely today – which of course won’t happen – there are 8 billion tonnes of plastic waste, large and small, circulating in the biosphere. »

These new discoveries offer a glimmer of hope: the planet’s microbes are beginning to adapt to this massive influx of waste and are beginning to at least break down some of it.

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Main image: Maksim Safaniuk / Shutterstock

• Jake Currie

  Published on November 7, 2025

  Jake Currie is a writer based in Brooklyn, New York.