FIG. 3.

Solid-state ¹³C NMR spectra of EPS from DS1 and DS2 biofilms, revealing the distribution of bonding environments. The spectral regions with relevance to the present study include the regions for peptide-bonded carbon (peptide), polysaccharide glycosidic carbon and secondary alcohols (area in the rectangle), and saturated hydrocarbon (lipids). Differences in the spectral features in the carbohydrate region indicate substantial differences in the compositions of the polysaccharides in the two biofilms.