In a significant scientific advance, researchers have confirmed the widespread existence of ocean bacteria that can break down and consume common plastics. Scientists from the King Abdullah University of Science and Technology (KAUST) led a global study, published in 2025, which discovered a distinctive molecular "fingerprint" in marine bacteria that allows them to digest polyethylene terephthalate (PET)—the durable material used in single-use water bottles and clothing.

The research, which analyzed over 400 ocean samples worldwide, found these plastic-degrading microbes in nearly 80% of tested waters. This biological adaptation signals nature's unexpected response to pervasive plastic pollution. However, scientists caution this natural process is far too slow to solve the pollution crisis alone. Instead, they say the discovery provides a critical template for engineering superior enzymes to revolutionize plastic recycling and waste management.

The Scale of the Plastic Problem

The discovery of plastic-eating bacteria comes against a backdrop of an escalating environmental emergency. An estimated 75 to 199 million tonnes of plastic already pollute the world's oceans, with millions more tonnes entering annually. This pollution breaks down into microplastics—particles smaller than 5 millimeters—which now contaminate every corner of the globe, from deep-sea trenches to mountain tops.

The contamination has entered the food chain and, consequently, our bodies. The average person now ingests tens of thousands of microplastic particles each year through food, water, and air. Researchers at Stanford University note that microplastics have been found in human blood, lungs, and placenta, transforming the issue from an ecological concern to a pressing question for human health. The full health implications are still being unraveled, but laboratory studies have linked plastic particle exposure to inflammation, cellular damage, and other toxic effects.

A Microbial Solution Evolves in the Deep

The KAUST team's breakthrough hinges on identifying a specific structural feature on a bacterial enzyme called PETase. This feature, dubbed the M5 motif, acts as a definitive marker that an enzyme can efficiently dismantle PET plastic into its basic chemical building blocks.

"The M5 motif acts like a fingerprint that tells us when a PETase is likely to be functional," explained Carlos Duarte, a marine ecologist and co-leader of the study. He describes the adaptation as a microbial innovation in resource-scarce environments. "In the ocean, where carbon is scarce, microbes seem to have fine-tuned these enzymes to make use of this new, human-made carbon source: plastic".

This finding builds on the 2016 discovery of Ideonella sakaiensis, a bacterium in a Japanese recycling facility that could consume PET. The new research confirms that similar capabilities have independently evolved across vast stretches of the global ocean, particularly in areas with high plastic pollution. Intikhab Alam, the study's co-leader, noted that in the nutrient-poor deep sea, the ability to digest this synthetic material could offer a key survival advantage.

From Pollution to Solution: Engineering a Fix

While the bacteria's natural degradation is too slow to clean the oceans, the discovery provides a powerful blueprint for science. Researchers can now study the most effective natural PETase enzymes and engineer optimized versions in the lab. The goal is to create biological tools that can rapidly break down plastic waste in controlled recycling facilities.

This field of biological recycling, or bioremediation, is already progressing. In separate work funded by the U.S. National Science Foundation, researchers at North Carolina State University have successfully genetically engineered a saltwater bacterium, Vibrio natriegens, to break down PET microplastics. By introducing genes from the Ideonella sakaiensis bacterium, they created a modified organism that can perform this digestion in a marine environment.

"This is the first genetically engineered organism that we know of that is capable of breaking down PET microplastics in saltwater," said Tianyu Li of NC State, first author of that paper. Such engineered solutions are aimed not at releasing organisms into the open ocean, but at creating efficient systems for processing collected plastic waste.

A Tool, Not a Panacea

Scientists universally stress that biological discoveries are not a substitute for drastically reducing plastic production and improving waste management. Duarte warns that relying on natural degradation is misplaced optimism. "By the time plastics reach the deep sea, the risks to marine life and human consumers have already been inflicted," he said.

The crisis continues to accelerate. A 2025 report warns that without decisive action, the total weight of plastic in the oceans could surpass the total weight of all fish by 2050. In response, international policy efforts are intensifying, including negotiations for a UN Global Plastic Treaty and expanded regulations on single-use plastics and producer responsibility.

The discovery of ubiquitous, plastic-digesting bacteria is a profound testament to nature's adaptability. It provides a potent new tool for humanity's toolkit—a biological template to help clean up the legacy of plastic pollution. However, experts agree that the primary solution must be to turn off the tap, reducing the flood of new plastic that continues to overwhelm the planet's ecosystems and, increasingly, our own bodies.