Multi-omics reveals wastewater sludge bacteria with genomic potential to degrade poly(ethylene terephthalate)

Plastic pollution is a growing concern, especially poly(ethylene terephthalate) (PET), one of the most produced plastic polymers. Although several microorganisms capable of degrading PET have been identified, little is known about those present in wastewater treatment plants (WWTPs). This study explores their ability to degrade PET and the enzymes involved. Activated sludge from two facilities-one urban WWTP and one industrial WWTP-was cultivated with PET of different crystallinities. The inoculum source primarily determined differences in microbial community composition. Metagenomics revealed more than 300 genes homologous to PET-degrading enzymes in all biofilms; however, metaproteomics confirmed expression of only a few of these enzymes in industrial WWTP-derived biofilms. This inoculum demonstrated the ability to degrade PET breakdown products within 24 h. In addition, FTIR analysis revealed initial signs of surface alteration. In conclusion, this study reveals the presence of microorganisms in industrial wastewater treatment sludge that possess the genetic potential to degrade PET.