Conversion of cheese whey into a fucose- and glucuronic acid-rich extracellular polysaccharide by Enterobacter A47

Cheese whey was used as the sole substrate for the production of extracellular polysaccharides (EPS) by Enterobacter A47. An EPS concentration of 6.40 g L−1 was reached within 3.2 days of cultivation, corresponding to a volumetric productivity of 2.00 g L−1 d−1. The produced EPS was mainly composed of glucuronic acid (29 mol%) and fucose (29 mol%), with lower contents of glucose and galactose (21 mol% each) and a total acyl groups content of 32 wt.%. The polymer had an average molecular weight of 1.8 × 106 Da, with a polydispersity index of 1.2, and an intrinsic viscosity of 8.0 dL g−1. EPS aqueous solutions (1.0 wt.% in 0.01 M NaCl, at pH 8.0) presented a shear thinning behavior with a viscosity of the first Newtonian plateau approaching 0.1 Pa s. This novel glucuronic acid-rich polymer possesses interesting rheological properties, which, together with its high content of glucuronic acid and fucose, two bioactive sugar monomers, confers it a great potential for use in high-value applications, such as cosmetics and pharmaceuticals.