biostudies-literatureWilkes RADivision of ChemistryBioenergy Technologies Office19338-19352https://www.ebi.ac.uk/biostudies/studies/S-EPMC11526368biostudies-literatureUnknown58(43)<i>Comamonadaceae</i> bacteria are enriched on poly(ethylene terephthalate) (PET) microplastics in wastewaters and urban rivers, but the PET-degrading mechanisms remain unclear. Here, we investigated these mechanisms with <i>Comamonas testosteroni</i>KF-1, a wastewater isolate, by combining microscopy, spectroscopy, proteomics, protein modeling, and genetic engineering. Compared to minor dents on PET films, scanning electron microscopy revealed significant fragmentation of PET pellets, resulting in a 3.5-fold increase in the abundance of small nanoparticles (<100 nm) during 30-day cultivation. Infrared spectroscopy captured primarily hydrolytic cleavage in the fragmented pellet particles. Solution analysis further demonstrated double hydrolysis of a PET oligomer, bis(2-hydroxyethyl) terephEnvironmental science & technologyMechanisms of Polyethylene Terephthalate Pellet Fragmentation into Nanoplastics and Assimilable Carbons by Wastewater <i>Comamonas</i>.PMC11526368DE-AC05-00OR22725CHE-2109097Zhou NWilson RSGuss AMAryal OAristilde LWilkes RACarroll ALKapoor AZhang LTeitel KPCastaneda EWaldbauer JRfalseMechanisms of Polyethylene Terephthalate Pellet Fragmentation into Nanoplastics and Assimilable Carbons by Wastewater <i>Comamonas</i>.<i>Comamonadaceae</i> bacteria are enriched on poly(ethylene terephthalate) (PET) microplastics in wastewaters and urban rivers, but the PET-degrading mechanisms remain unclear. Here, we investigated these mechanisms with <i>Comamonas testosteroni</i>KF-1, a wastewater isolate, by combining microscopy, spectroscopy, proteomics, protein modeling, and genetic engineering. Compared to minor dents on PET films, scanning electron microscopy revealed significant fragmentation of PET pellets, resulting in a 3.5-fold increase in the abundance of small nanoparticles (<100 nm) during 30-day cultivation. Infrared spectroscopy captured primarily hydrolytic cleavage in the fragmented pellet particles. Solution analysis further demonstrated double hydrolysis of a PET oligomer, bis(2-hydroxyethyl) tereph2024-01-01T00:00:00Z2024 Oct2026-06-01T09:55:20.414Z2025-04-06T09:32:21.049ZS-EPMC115263683936073310.1021/acs.est.4c06645