Plastic trash is reaching some of the most remote places in the world, from the bottom of the Mariana Trench to the top of Mount Everest. Hundreds of plastic-eating microorganisms have been discovered over the past quarter century that could help us clean up, but there’s a long way to go before they work in the natural environment. Digestion of plastic by microorganisms remains slow, requires high temperatures, and can only proceed efficiently in bioreactors. Furthermore, most of the plastic-eating microorganisms discovered so far can only digest one type of plastic.
One solution is to combine different microorganisms to work as a team to tackle plastic pollution. This allows you to share tasks, compensate for each other’s weaknesses, and continue working even when environmental conditions change. Now, German scientists have discovered a synergistic “consortium” of plastic-eating bacteria. This bacteria can feed on phthalate esters (PAEs). PAEs are plasticizers commonly found in building materials, food packaging and personal care products that have been implicated in hormonal, metabolic and developmental disorders and some cancers. The result is Frontiers of microbiology.
“Here we show the degradation of various phthalate esters (PAEs) by the joint activity of several bacterial strains,” said corresponding author Dr. Christian Eberlein, a postdoctoral researcher at the Helmholtz Center for Environmental Research in Leipzig. Eberlein and his colleagues are participants in the Helmholtz Sustainability Challenge project FINEST, which aims to design new solutions for a sustainable circular economy.
Strength through diversity
Eberlein and his colleagues knew a promising place to look for new plastic-eating microbes. It lives as a biofilm on polyurethane tubes in a bioreactor in our laboratory. They scraped the sample and incubated it in a growth medium using the PAE diethyl phthalate (DEP) as the carbon and energy source. We focused on DEP because it is a typical model compound used in experiments with phthalate plasticizers. Successive transplants between cultures eventually resulted in stable colonies that could grow at DEP concentrations up to 888 milligrams per liter. At 30 °C, it took 24 h for the consortium to completely consume DEP.
DNA sequencing showed that the three bacterial species constituted a consortium. Pseudomonas putida and Pseudomonas fluorescens groups and unknown groups microorganisms seed.
It was proven that bacteria cannot digest PAE alone and must work as a cooperative. Further experiments showed that this synergistic superpower is due to so-called “cross-feeding,” in which one microbe releases metabolic byproducts that are taken up by its partner as nutrients, sharing resources to form a stable and diverse community. Cross-feeding is a fundamental feature of natural microbial communities, but it has not been previously demonstrated in plastic-eating bacteria. In this case, the main intermediate products turned out to be PAEs themselves: monoethyl phthalate and phthalate esters. Proteomic analysis has shown that the enzymes needed to break down these compounds are new to science.
Importantly, this consortium is metabolically versatile. In addition to DEP, we were able to digest all common PAEs, including dimethyl phthalate, dipropyl phthalate, and dibutyl phthalate.
“This broad substrate range increases the potential value of the consortium in biotechnological and environmental applications, as it has the potential to degrade multiple PAEs commonly found as plasticizers in contaminated environments,” the authors wrote.
Recent advances due to the plastic era
How did this remarkable ability to digest PAEs evolve?
“The first reaction relied on existing enzymes that originally evolved to break down natural molecules containing ester bonds. Since then, sustained contamination with PAEs in nature likely created strong evolutionary pressures that forced microorganisms to adapt and develop more specialized enzymes that could break down PAEs more efficiently,” Eberlein speculated.
The consortium is not yet able to work with other types of plastics than PAE. For example, polyethylene and polypropylene contain highly resistant nonester bonds that are inaccessible to natural enzymes.
The next step is to test the new consortium on real wastewater samples containing microplastics and evaluate its ability to remove PAEs. Introducing these bacteria into contaminated natural environments, a process known as bioaugmentation, may help reduce PAE contamination in real-world environments. ”
Dr. Hermann Hypieper, senior scientist at the Helmholtz Center and lead author of the study
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Reference magazines:
Bertoldi, S. Others. (2026). Cross-feeding promotes the degradation of phthalate plasticizers within the bacterial consortium. Frontiers of microbiology. DOI: 10.3389/fmicb.2025.1757196. https://www.frontiersin.org/journals/microbiology/articles/10.3389/fmicb.2025.1757196/full
