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ARS Home » Southeast Area » New Orleans, Louisiana » Southern Regional Research Center » Commodity Utilization Research » Research » Research Project #443398

Research Project: Role of Bacterial Exopolysaccharide Composition and Structure in Biofilm Formation, Viscosity and Susceptibility to Dextranase Processing Aid

Location: Commodity Utilization Research

Project Number: 6054-41000-114-008-S
Project Type: Non-Assistance Cooperative Agreement

Start Date: Aug 1, 2023
End Date: Aug 31, 2027

Characterize exopolysaccharides (EPS) produced by bacterial isolate cultures and biofilms. Determine size, glycosyl composition, linkage, and branching of EPS and investigate susceptibility of EPS structures to dextranase enzyme.

This work will be conducted over four years. EPS and biofilm samples produced by bacterial strains of interest will be sent to the Cooperator for structural analysis. The Cooperator specializes in methods to analyze and perform any extra purification that might be required on biofilms in order to perform structural analysis. The progress of the purification and the chemical nature of the analyzed sample will be obtained by glycosyl composition analysis of monosaccharides (e.g., per-O-trimethylsilyl (TMS)-methyl glysosides, aldtiol acetates, heptafluorobutyric anhydride- methyl glycosides) utilizing gas chromatography-mass spectroscopy (GC-MS)/gas chromatography-flame ionization detector (GC-FID)/gas chromatography-chemical ionization (GC-CI) or high-performance anion exchange chromatography/pulsed amperometric detection (HPAEC) analysis of mono- and oligosaccharides. The structural properties of the polysaccharide are revealed by combining monosaccharide composition with glycosyl linkage of neutral and acidic sugars by the method of partially methylated alditol acetates (PMAA). Glycosyl sequence of the complex carbohydrates will be determined by performing 1D and 2D homo- and heteronuclear Nuclear Magnetic Resonanace (NMR). A high-resolution matrix assisted laser desorption ionization-time of flight-mass spectroscopy (MALDI-TOF) MS and MS/MS electrospray ionization (ESI-MS) mass spectrometry further supports the structural properties of the polysaccharides. Molecular weight and complexity of large polymers can also be determined by size exclusion chromatography (SEC)-multi-angle light scattering (MALS).