Bacterial degradation of plasticizers on the example of diethyl phthalate (DEP)

The continuing reports of plastic pollution in various ecosystems highlight the threat posed by the ever-increasing consumption of synthetic polymers. Plastics are frequently associated with additives such as phthalic acid esters. Such compounds are used as plasticizers to provide flexibility to plastic products and as common additives in various consumer products, and suspect to cause endocrine disruption in animals.

The bacterial degradation of diethyl phthalate (DEP) as a model compound for plasticizers was studied. In order to isolate bacterial DEP degraders, a biofilm present on a polyurethane tubing was scratched off. From this biofilm, a microbial consortium containing two strains Microbacterium ginsengisoli and Pseudomonas canadensis was isolated. These strains were further characterized and found to be capable to grow in mineral medium with DEP as sole carbon energy source. The complete degradation of up to 4 mM DEP was confirmed by UPLC analysis. Furthermore, the substrate spectrum of the microbial consortium was assessed by testing different carbon sources like phthalic acid, 3,4-Dihydroxybenzoic acid, and other phthalate esters. Based on that and on the metagenome of the bacterial consortium, a degradation pathway of DEP was suggested.