For years, scientists have searched for bacteria that can eat plastic. MIT researchers have now found something more complex and more interesting: the ocean breaks down plastic through bacterial teamwork — a relay system of microbial species that pass the job between them.
The study, published in Environmental Science and Technology on March 16, 2026, reveals why biodegradable plastics can degrade quickly in some ocean environments and persist in others — and offers a roadmap for designing better materials and cleanup strategies.
How It Works
The MIT team placed samples of an aromatic aliphatic co-polyester — a common biodegradable plastic used in shopping bags, food packaging, and agricultural film — in the Mediterranean Sea to allow natural bacterial biofilms to form. They then analysed what happened next.
They identified Pseudomonas pachastrellae as the key initiator: a bacterium capable of depolymerising the plastic — breaking it down from long chains into its constituent chemical building blocks: terephthalic acid, sebacic acid, and butanediol.
But here's the key insight: Pseudomonas pachastrellae alone couldn't consume all three components. The job required a community of bacterial species, each handling different products of the breakdown chain. Remove one species, and the process stalls.
Why This Changes Things
"It is rare for a single bacterium to fully degrade plastic due to the substantial metabolic burden required," the researchers noted. "Different bacterial species work together, with one initiating the breakdown and others consuming the simpler molecules."
This explains an enduring puzzle in plastic biodegradation research: why the same biodegradable material will disappear in one ocean location but persist almost unchanged in another. The answer is the specific microbial community present — and those communities vary enormously by location, depth, temperature, and season.
Implications for Cleanup and Design
The findings have two major practical implications:
- Better plastic design: Understanding which bacterial communities drive degradation allows materials scientists to design biodegradable plastics that are more likely to break down reliably in real ocean conditions, not just in controlled composting environments.
- Novel recycling systems: The multi-species relay could be engineered or cultivated deliberately — creating microbial consortia that efficiently convert plastic waste into useful chemical resources.
The research moves the field beyond a hunt for a single "plastic-eating superbug" toward a more realistic and ultimately more powerful understanding of how nature actually works.
Source: Environmental Science and Technology, MIT, March 16, 2026
