Researchers at the University of Konstanz have identified an enzyme that allows bacteria to break down certain biodegradable plastics—and, unexpectedly, penicillin. The enzyme’s unusually wide active site has earned it the nickname “Pac-Man.” Its ability to attack both plastic polymers and an antibiotic suggests a possible connection between plastic degradation and antibiotic resistance.
The team, led by biologists Harry Lerner and David Schleheck, buried films of long-chain aliphatic polyester (LCAP) bioplastic in forest soil and tracked decomposition over a year. All bioplastic materials tested were fully degraded within roughly 250 to 330 days. Cellulose broke down in about 80 days, while conventional high-density polyethylene (HDPE) showed virtually no degradation.
The findings, published in The ISME Journal, indicate that some bacteria are adapting faster than expected to digest certain plastics. However, the authors stress a key limitation: microbes can only meaningfully reduce plastic pollution if more products are made from biodegradable materials with chemical bonds that enzymes can attack.