Animals degrade microbial PHAs discovery

Researchers at the Max Planck Institute for Marine Microbiology in Bremen, Germany, published a study in Nature Ecology & Evolution on August 13, 2026, showing that a wide range of animals possess enzymes capable of degrading microbial polyhydroxyalkanoates (PHAs), natural biodegradable plastics previously thought to be broken down only by microorganisms. The discovery began with the gutless marine worm Olavius algarvensis, which digests symbiotic bacteria storing large amounts of PHA. The team identified an enzyme, polyhydroxyalkanoate depolymerase (PHAD), in the worm and found related enzymes in more than 66 animal species across nine phyla, including sponges, earthworms, and springtails. Laboratory tests confirmed that enzymes from distantly related animals can degrade microbial PHAs. This finding suggests that animals can access microbial carbon reserves, potentially altering understanding of carbon cycling in ecosystems. It also adds animals to the list of organisms that may participate in the degradation of PHA-based bioplastics, which are increasingly used as sustainable alternatives to conventional plastics in packaging, agriculture, and medical applications. The researchers caution that the ecological significance and frequency of animal-mediated PHA degradation remain unknown.