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Time Evolution of Bacterial Extracellular Polymer Composition Studied with a Versatile Infrared Transmission Array Scanner

Hennecker, Christopher D., Jarisz, Tasha A., Hore, Dennis K.
Journal of physical chemistry 2019 v.123 no.11 pp. 6635-6641
Escherichia coli K12, Fourier transform infrared spectroscopy, bacterial adhesion, bacterial growth, cations, chemical composition, neutralization, nucleic acids, physical chemistry, polymers, scanners
The chemical composition of extracellular polymeric substances (EPSs) secreted by Escherichia coli K12 in solution was monitored as a function of time over various stages of bacterial growth. We have observed that the spectra become enhanced at 1132 and 980 cm–¹, which is attributed to an increasing fraction of uronic and nucleic acids within the polymer matrix. Both of these acidic molecules have been shown to sequester cations from solution to neutralize their negative charge. We discuss the implication for this composition profile change in terms of previously observed restructuring of interfacial water molecules during the earliest stages of bacterial adhesion. To monitor each fraction of EPS under the same conditions, we illustrate the design and operation of a high-throughput array scanner fitted to a Fourier transform infrared spectrometer.