FT-IR spectroscopy analysis
To determine the composition of the exopolysaccharides,
complete acid hydrolysis thereof was carried out with
4.95 N trifluoroacetic acid (TFA) at 80 °C in a heating
block for 4 h. The mixture was cooled to room temperature, evaporated, and then analysed with infrared spectroscopy. FT-IR spectroscopy was recorded with a spectrometer (Thermo Scientific Nicolet 8700A with an FT
Ramana Nicolet NXR module) in the wavelength range
4,000–400 cm-1.