Microplastics as vectors for microbial transport: experimental interaction with Escherichia coli.

Microplastics (MPs) are recognized as vectors for microorganisms in aquatic ecosystems, raising concerns about their environmental implications. We examine the structural and chemical properties of recycled PET microplastics and their interactions with Escherichia coli (E. coli) using Fourier-transform infrared (FTIR) and Raman spectroscopy. FTIR analysis identified nine characteristic vibrational bands of PET, and Raman spectroscopy confirmed that neither glutaraldehyde treatment nor bacterial exposure produced significant chemical changes in the PET structure. Scanning electron microscopy (SEM) and Gram staining revealed bacterial adhesion and biofilm formation on microplastic surfaces. Additionally, E. coli colonies exhibited reduced lactose fermentation activity. These findings reinforce the role of MPs as microbial vectors and demonstrate the ability of E. coli to colonize synthetic polymers. The development of rapid spectroscopic tools could enhance monitoring efforts in both laboratory and field environments. This study contributes to the growing understanding of MPs-microorganism interactions, and a model system of MPs-microorganism interaction is proposed.