Nature is evolving a new way to digest our plastic waste
For decades, we believed synthetic plastics were nearly impossible to degrade naturally. However, new research reveals that marine microbes are rapidly adapting to our pollution, developing specialized enzymes that allow them to use plastic as a vital, man-on-made carbon source.
While plastic is a ubiquitous building block of modern life—found in everything from clothing to bottles [S1:p1]—it has long been considered a permanent fixture in our environment. That perception is shifting. Scientists at the King Abdullah University of Science and Technology (KAUST) have identified bacteria in the ocean that have evolved specialized enzymes to digest polyethylene terephthalate (PET), the tough plastic used in fabrics and drink bottles [S2:p2].
The breakthrough lies in a specific molecular signature known as the M5 motif. This feature acts as a functional fingerprint on an enzyme called PETase, distinguishing true plastic-degrading enzymes from inactive look-alikes [S2:p2, S2:p4]. By using artificial intelligence modeling and genetic screening, researchers confirmed that these enzymes evolved from older hydrocarbon-degrading enzymes, fine-tuned by microbes to exploit plastic as a new source of carbon in nutrient-poor environments [S2:p3].
This adaptation is widespread. In a study of over 400 global ocean samples, functional PETases containing the M5 motif were found in nearly 80% of the tested waters, from surface gyres to depths nearly two kilometers below [S2:p5]. However, experts urge caution. While this shows incredible microbial resilience, the process is far too slow to counteract the 14 million tons of plastic offloaded into our oceans annually [S3:p2, S2:p6]. As marine ecologist Carlos Duarte warns, the ecological damage is often done by the time these plastics reach the deep sea [S2:p6].
Source: Can Bacteria Eat Plastic?
