Bacteria baked into plastic break the material down in six days

A lab plastic seeded with dormant bacteria fully decomposed in six days without leaving microplastics, so far tested on one polymer.

Researchers have made a 'living plastic' that carries dormant engineered bacteria inside it. When activated, the bacteria digest the surrounding polymer, and in the study the material fully decomposed within six days without producing microplastics. The work was published in ACS Applied Polymer Materials, with Zhuojun Dai as a corresponding author.

The team engineered Bacillus subtilis to make two enzymes that work in sequence: the first cuts polymer chains at random points into shorter sections, and the second breaks those fragments down from their ends into individual monomers. They combined dormant bacterial spores with polycaprolactone, a polymer used in 3D printing and some surgical sutures. The finished material had mechanical properties similar to ordinary polycaprolactone film. Activation required a nutrient broth heated to 50 degrees Celsius. A wearable plastic electrode built from the material worked as intended and degraded fully within two weeks after activation.

Plastic's cost is not only in making it but in the pollution it leaves behind. A material that dismantles itself into monomers, rather than shedding persistent microplastics, would shift that burden off shared land and water — the commons everyone draws on for free.

The caveats are real. Experiments covered a single polymer. The team hopes to trigger the spores with water rather than heated broth but has not yet done so, and adapting the approach to common disposable plastics remains an aspiration, not a result.

Source: ScienceDaily