What they found
A team at the University of Konstanz buried films of a next-generation bioplastic in forest soil for over a year: LCAPs, polyesters derived from vegetable oils, engineered to be as tough as polyethylene yet biodegradable. On recovery, the surface was pitted with cavities the size of bacterial cells — a sign something was eating it. By sequencing the DNA of the microbes grown on the plastic, the researchers isolated a previously undescribed enzyme, named LCPH1. Its structure, modelled by computer, revealed an unusually wide and open active site — a "mouth" able to grab bulky molecules. Hence the nickname: the "Pac-Man" enzyme. In the lab, the purified enzyme broke the bioplastic down into its building blocks in amounts comparable to PETase, the most famous plastic-eating enzyme. In soil tests, the bioplastics degraded almost completely in 8-10 months.
Why it's good news
The encouraging message is that soil microbes are adapting to the new bioplastics faster than expected — it took just a few years for an enzyme able to digest them to emerge in an ordinary forest. And it points to a clear path: if we design plastics with biochemical "weak spots", like the ester bonds in LCAPs, nature has the tools to dispose of them. It's the opposite of common plastics, which linger in the environment for centuries precisely because no enzyme recognizes them. As David Schleheck, one of the study's authors, puts it: we humans "must meet the microbes halfway" — use materials they already know how to break apart.
What it doesn't mean
It doesn't mean we have an enzyme that can make scattered plastic disappear. LCPH1 eats bioplastics built specifically to degrade, not the PET of bottles nor the polyethylene of bags. And even on bioplastics, the fieldwork showed a clear limit: without enough water and nutrients — normal conditions in many real soils — degradation slows and stays incomplete. Then there's the twist that makes the discovery ambiguous: the same enzyme disables penicillin and ampicillin. The authors hypothesize that, in this way, exposure to plastic could favour the selection of antibiotic-resistant bacteria. It's a hypothesis with grounds — biofilms on plastic are already known to accumulate resistance genes — but it's not proven that this enzyme makes pathogens dangerous in the wild.