Animals have been digesting natural bioplastic for millions of years, study finds
Researchers discovered that dozens of animal species possess enzymes that break down microbial polyhydroxyalkanoates, a natural biodegradable plastic, suggesting they have been consuming it for hundreds of millions of years.
Scientists at the Max Planck Institute for Marine Microbiology have shown that many animals can break down polyhydroxyalkanoates (PHAs), the biodegradable polymers naturally produced by bacteria and archaea. The research started with the gutless marine worm Olavius algarvensis, which lacks a digestive tract and relies on symbiotic bacteria that store large amounts of PHA; the worm was found to produce an enzyme that cleaves these polymers.
Expanding the search, the team detected related enzymes in more than 66 species spanning nine animal phyla, including a sponge, an earthworm and a springtail, and demonstrated their PHA-degrading capability in laboratory assays. This suggests that animals have been accessing microbial carbon reserves for hundreds of millions of years, adding a new dimension to the global carbon cycle. PHAs are also used in industrial bioplastics for packaging, agriculture and medical devices, but their environmental breakdown pathways were thought to involve only microbes. The study, published in Nature Ecology & Evolution, highlights the broader ecological role of animals in degrading natural bioplastics.
Why it matters
It reveals a hidden biological process that links microbes and animals in carbon recycling and informs bioplastic sustainability.
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