Plastic-Eating Bacteria Are Taking Over the Oceans

Scientists have discovered that plastic-eating bacteria capable of degrading PET plastic are now present across nearly every ocean, highlighting how marine life is evolving in response to human pollution. The findings, published by researchers at King Abdullah University of Science and Technology (KAUST) and in The ISME Journal, November 2025 suggest that microbes in the ocean are adapting rapidly to survive in environments increasingly contaminated with plastic waste.

Plastic pollution has become one of the most pressing environmental challenges of the 21st century. PET, or polyethylene terephthalate, is widely used in bottles, food packaging, and synthetic fabrics. It is highly resistant to natural degradation and accumulates in the ocean for decades. However, recent research indicates that some marine bacteria have evolved enzymes capable of breaking PET into smaller molecules that can serve as food for microbes.

PETase: The Enzyme That Turns Plastic into Food

The key to this discovery is the enzyme PETase, which functions like a molecular pair of scissors. PETase breaks PET plastic into smaller compounds, including MHET, terephthalate (TPA), and ethylene glycol, which bacteria can metabolize as carbon and energy sources.

In the study, scientists analyzed 415 seawater samples collected from oceans worldwide. PETase enzymes were detected in 80% of all locations, from surface waters down to depths of 2,000 meters. The researchers also identified a structural feature called Motif M5, which enhances PETase activity, making these ocean bacteria more efficient at breaking down plastic than previously studied terrestrial bacteria.

“In oceans where natural carbon sources are scarce, microbes appear to be adapting to use a human-made source of carbon: plastic,” said one of the lead researchers from KAUST.

The study also revealed that bacteria in the order Pseudomonadales are among the primary carriers of PETase genes. Interestingly, these genes appear to have evolved independently in multiple oceanic regions, suggesting convergent evolution driven by widespread plastic pollution.

Global Adaptation in the Deep Sea

What makes these findings remarkable is that PETase-carrying bacteria are not confined to polluted surface waters. Many samples containing these bacteria were collected at depths exceeding 1,500 meters, where sunlight does not penetrate and organic food sources are limited.

“The deep ocean represents an extreme environment,” said one of the co-authors of the study. “Yet, we are seeing microbial adaptation to human pollution even at these depths. It shows the resilience and adaptability of life in the oceans.”

The discovery provides a striking example of how human activity can influence microbial evolution on a global scale. Plastic, a man-made material, is now a driver of evolutionary change in marine microorganisms.

Hope, But Not a Complete Solution

While the findings are encouraging, scientists caution that these bacteria are not a silver bullet for the global plastic crisis. Most plastics in the ocean consist of polyethylene (PE) and polypropylene (PP), which are far more resistant to microbial degradation than PET. Furthermore, the rate at which these bacteria can break down plastic is currently too slow to offset the enormous amounts of plastic entering oceans each year.

There are also ecological concerns. Rapid expansion of plastic-degrading bacteria could alter microbial communities and affect food webs in ways that are not yet fully understood.

Nonetheless, researchers see potential for biotechnological applications. PETase enzymes could be harnessed for eco-friendly recycling, industrial plastic degradation, or targeted bioremediation efforts in polluted marine environments.

“This discovery gives us a blueprint for developing solutions that are inspired by nature,” one researcher said. “However, reducing plastic production and waste remains critical.”

The emergence of plastic-eating bacteria underscores a sobering reality: human pollution is driving evolutionary changes in marine ecosystems. Oceans are not passive; they are responding to human activity, and life at the microbial scale is adapting in ways that scientists are only beginning to understand.

The findings highlight both the resilience of life and the unintended consequences of human impact. While PETase-carrying bacteria offer a glimpse of hope, they also serve as a warning. Without significant reduction in plastic waste, the oceans’ response may not be enough to prevent environmental damage.

Plastic-eating bacteria may represent nature’s early response to human pollution, but the survival of the oceans—and humans—still depends on collective action to reduce, reuse, and recycle plastic. (Wage Erlangga)