Soil enzyme LCPH1 cuts a plant-oil plastic and knocks out penicillin

Biologists studying a plant-oil bioplastic have isolated a soil enzyme that does two jobs at once. It breaks long-chain aliphatic polyester, a material sold as a biodegradable plastic, into its parts. It also cuts penicillin and ampicillin and leaves those drugs unable to kill bacteria. The enzyme is named LCPH1. The work was reported on 7 September.

The team buried strips of the plastic, abbreviated LCAP, in forest soil for more than a year. Microscope images later showed pits the size and shape of bacteria on the surface. DNA from the microbes living on the strips pointed to an enzyme whose sequence sits close to the proteins bacteria use to disable penicillin-class drugs. Structural models show a wide, open active site. The researchers described the shape as wide enough to close on a plastic chain or on an antibiotic molecule.

Dr. Lerner, quoted with the paper, said the structure looks like an esterase and also like a beta-lactamase. Beta-lactamases open the four-atom ring that gives penicillin its punch. Once that ring is broken the drug is spent. LCPH1 does that to penicillin and ampicillin in the same laboratory setup that reduces the bioplastic to monomers.

That overlap is the part that leaves the soils paper and enters public health. An enzyme that was selected to eat a polyester in dirt can also shred a hospital drug. The study does not claim that LCAP use on farms will spread penicillin resistance through a field. It does show that the chemical similarity between an ester bond in a plant-oil plastic and the bond a beta-lactamase attacks is close enough for one protein to handle both.

Long-chain aliphatic polyesters are sold as a cleaner substitute for petrochemical film. They are meant to disappear in soil or compost. The year-long burial confirms that some forest microbes will eat them. The same experiment now attaches a second fact: the tool those microbes use is a cousin of a resistance enzyme. Any plan to concentrate LCPH1 as a recycling agent will have to treat spent enzyme as a biological material, not as a household catalyst.

Separate 2026 work on other plastics does not collapse into this result. A Bacillus strain labelled PE4 has been reported to reduce polyethylene mass under heat and alkaline conditions. Mangrove-soil surveys have turned up candidate PETases. Those are different polymers and different proteins. LCPH1 is specific, in the published account, to the oil-based polyester and to the two beta-lactam drugs tested. Mixing the headlines would be a mistake.

The next measurements are practical. How fast LCPH1 works on a film at outdoor temperatures. Whether it acts on polyethylene or PET, or only on this polyester. Whether a gram of the same forest soil that yielded LCPH1 also shows faster penicillin breakdown than a control gram. Those tests decide whether the finding is a fact about one bioplastic or a broader fact about how plastic-eating proteins sit next to antibiotic-eating ones.

For now the public takeaway is a pair of facts that do not usually share a sentence. A buried plant-oil plastic came out pitted by bacteria. The protein those bacteria used can also take the killing power out of penicillin and ampicillin. Anyone writing a rule for biodegradable film has to keep both facts on the same page.