Ancient PHA bioplastic fed animals for 300 million years

Scientists have uncovered that the natural bioplastic polyhydroxyalkanoate (PHA) – a carbon‑rich polymer produced by bacteria and archaea – has been a staple in the diets of countless animals for more than 300 million years. The finding, reported by a team of microbiologists in a Phys.org release, shows that PHAs were not just cellular storage molecules but also a food source that fed a wide range of organisms through deep time. The study examined fossilized microbial mats and modern microbial communities to trace the long‑term use of PHAs in the food web.

The discovery matters because PHAs are fully biodegradable and chemically similar to the plastics that clog rivers, oceans, and landfill sites today. By understanding how nature has used and recycled this polymer for eons, scientists can learn how to design sustainable, bio‑based plastics that break down harmlessly. The research also highlights the resilience of microbial ecosystems, which have evolved to produce PHAs as a way to store excess carbon and survive periods of scarcity. In the modern era, this knowledge could help engineers create materials that mimic these natural processes, potentially reducing the environmental footprint of our plastic industry.

In the study, the researchers quantified PHA concentrations in ancient microbial mats and found that up to 10 % of the biomass was stored as these polymers. They also identified specific bacterial lineages that consistently produce PHAs, suggesting a long‑term evolutionary strategy. Dr. Elena Ruiz, a microbial ecologist involved in the research, said the data show a “robust, ancient relationship between microbes and their environment that has shaped food chains for hundreds of millions of years.” The team used advanced imaging and isotope tracing to confirm that PHAs were not merely byproducts but actively consumed by larger organisms, including early invertebrates and algae.

Looking ahead, the team plans to collaborate with materials scientists to scale up PHA production using engineered bacteria. Pilot projects are already underway to grow PHAs in bioreactors fed with agricultural waste, aiming to produce commercial‑grade bioplastics at a lower cost than current options. If successful, these efforts could provide a viable alternative to fossil‑fuel‑based plastics, helping to curb plastic pollution while tapping into a process that has worked for life on Earth for millions of years.