A research team at the University of Konstanz has found a bacterial enzyme in forest soil that attacks two stubborn classes of compounds at once: long-chain polyester bioplastics and beta-lactam antibiotics such as penicillin. Because of its strikingly wide-open active site, the researchers named the molecule the „Pac-Man enzyme“. The study appeared on 2 September 2026 in The ISME Journal.
Two functions in one molecule
The molecule is a so-called family-VIII esterase, held firmly to the bacterial cell surface by a lipid anchor. It breaks long-chain aliphatic polyesters down into their building blocks (monomers) – while also cleaving the beta-lactam ring of penicillin. The researchers attribute this dual role to its structural kinship with beta-lactamases, the enzymes bacteria use to neutralise antibiotics.
Slow, but complete
Bioplastic films buried in forest soil degraded completely within roughly 250 to 330 days, whereas conventional HDPE plastic remained virtually untouched. Electron microscopy revealed bacteria burrowing into the film and leaving behind micron-sized holes.
Still laboratory work
The findings come from controlled lab and soil experiments; how the enzyme behaves in the open environment or at industrial scale remains unknown. The result is intriguing on two counts: as a potential tool for degrading plastics, and as a clue to how antibiotic resistance arises in soil.
Source: University of Konstanz / EurekAlert, press release of 2 September 2026; Lerner et al., The ISME Journal (2026), DOI 10.1093/ismejo/wrag203. Read the press release.
