3. Characterization of exopolysaccharides

These exopolysaccharides must then be assessed for their suitability by chemical analysis (overall composition, monosaccharide composition and ratios, presence of proteins as an indicator of purity, presence of organic and inorganic substituents), physicochemical characteristics (e.g. thermostability) and rheological characteristics (e.g. viscosity). Overall composition is determined by simple spectro-colorimetric techniques, with the necessary precautions for interpretation. The same applies to Fourier Transform Infrared (FTIR) analysis, which can nevertheless provide additional information on the presence of proteins, carboxyl (COOH) and ester groups, and sulfates. The nature and ratio of monosaccharides can be determined by various approaches. The most commonly used are gas chromatography coupled, where appropriate, with mass spectrometry and HPLC (liquid chromatography). Proton or carbon-13...