Scientists at the University of Konstanz have discovered an enzyme in soil bacteria capable of breaking down both certain types of bioplastic and penicillin antibiotics.
The researchers buried strips of LCAP bioplastic — a long-chain aliphatic polyester derived from plant oils — in the forest soil of the university's botanical garden for more than a year.
Under the microscope, tiny indentations of bacterial shape appeared on the material — a clear sign that microbes were actively "eating" the surface.
DNA sequencing of the microbes living on the plastic allowed the isolation of the enzyme LCPH1. Its structure resembles beta-lactamases — proteins that bacteria use to inactivate penicillin.
The enzyme's active site has an unusually wide "mouth" shaped like Pac-Man, capable of capturing both long plastic chains and antibiotic molecules.
In laboratory tests, LCPH1 successfully broke down bioplastic into monomers and simultaneously destroyed penicillin and ampicillin, stripping them of their ability to kill bacteria.
"The enzyme's structure resembles both esterases and beta-lactamases, which cleave the beta-lactam ring of penicillin, making bacteria resistant to antibiotics," noted lead author Harry Lerner.
Senior author David Schleheck added that plastic has only been present in the environment in significant amounts for 50–75 years, and microbes are already beginning to adapt to its degradation faster than expected.
The work is published in The ISME Journal. How will this discovery affect the fight against bacterial antibiotic resistance in the long term?
