The Enzyme Revolution: Breaking Down Microplastics in the Ocean

Microplastic pollution is one of the most pressing environmental crises of our time. Every year, millions of tons of tiny plastic particles—fragments from larger plastic items, synthetic fibers from clothing, and microbeads from cosmetics—end up in the world’s oceans. These pollutants infiltrate marine ecosystems, threaten wildlife, and even enter the human food chain through seafood consumption. While traditional cleanup efforts focus on collecting larger plastic debris, scientists have turned to an innovative solution: enzymes that can break down microplastics at a molecular level.

Microplastics, defined as plastic particles smaller than 5 millimeters, pose a severe threat to marine life. Fish, plankton, and seabirds mistake them for food, leading to digestive blockages, reduced nutrient absorption, and even death. Additionally, these plastics act like sponges, absorbing toxic pollutants such as heavy metals and industrial chemicals. When marine organisms ingest microplastics, these toxins accumulate in their bodies, potentially making their way up the food chain and onto human plates.

Because microplastics are so small and dispersed, traditional cleanup methods like nets and filtration systems struggle to remove them effectively. This has led researchers to explore biological approaches—specifically, the use of plastic-eating enzymes—to degrade microplastics naturally in the ocean.

In recent years, scientists have discovered naturally occurring enzymes that can break down plastics at the molecular level. One of the most famous examples is PETase, an enzyme found in a species of bacteria (Ideonella sakaiensis) that feeds on polyethylene terephthalate (PET), a common plastic used in water bottles and food packaging. First identified in a Japanese waste site in 2016, PETase has since been genetically modified to work faster and more efficiently.

More recently, researchers have identified other enzymes, such as MHETase, which works alongside PETase to accelerate plastic breakdown. A breakthrough study in 2022 further improved PETase by engineering a “super enzyme” capable of degrading plastics six times faster than before. This advancement has raised hopes for using enzymes to clean up microplastics in marine environments.

Another promising discovery is LLDPEase, an enzyme capable of breaking down low-density polyethylene (LDPE), which is found in plastic bags, packaging film, and other common plastic items. Scientists have been studying its potential for breaking down microplastics in the ocean, with preliminary results showing promising degradation rates.