LAUSR

Environmental pollution caused by commodity plastics has become a global issue. As a result, biodegradable plastics have found multiple applications in recent years, particularly in the manufacture of food packaging containers. However, microbes present in fermented foods have been found to degrade biodegradable plastics. In this study, we report, for the first time, a poly(3-hydroxybutyrate) (P(3HB))-degrading bacterium isolated from a type of washed rind cheese, Pont-l'évêque lait cru. The P(3HB)-degrading isolate, designated as PONα, was characterized in detail. The strain was found to be gram-positive and filamentous-shaped; the DNA G+C content was 71.6 mol%, and anteiso-C15:0 was found to be the major fatty acid. The strain grew well in the range of 37–40 °C and formed a large clear zone on P(3HB) medium at 37 °C. The phenotypic properties and phylogenetic inference indicated that strain PONα is closely related to Cellulosimicrobium cellulans. Strain PONα formed a clear zone on P(3HB), LB with P(3HB), poly(3-hydroxybutyrate-co-3-hydroxyvalerate) (PHBV), and chitin media plates, whereas no clear zone was found on poly(ethylene succinate) (PESu), poly(butylene succinate) (PBSu), poly(ε-caprolactone) (PCL), poly(lactic acid) (PLA), poly(butylene adipate-co-butylene terephthalate) (PBAT), poly(butylene succinate-co-butylene adipate) (PBSA), and olive oil media plates. Relatively higher P(3HB) hydrolytic activity was observed in the culture supernatant under the co-existence of P(3HB) and the cheese, suggesting that a component of the cheese plays an important role in the hydrolytic activity. These results indicate that microbiota in fermented foods such as cheese can degrade biodegradable plastics, thereby reducing their quality. Therefore, because P(3HB) may be degraded by the microbiota present in cheese, these findings may affect the application of P(3HB) in cheese packaging.