Bioconversion of cheese whey into a hetero-exopolysaccharide via a one-step bioprocess and its applications

Continuing efforts have been made to produce functional exopolysaccharides (EPSs) using cheap substrates for valuable applications. Cheese whey is a lactose-rich byproduct of cheese-producing industries. In this research, a one-step bioprocess for the bioconversion of cheese whey to a hetero-exopolysaccharide using a ropy EPS producing strain Lactobacillus plantarum JNULCC001 with high beta-galactosidase activity was performed. The prepared hetero-exopolysaccharide is named EPS-001 and composed of galactose, glucose, mannose, and arabinose with several functional groups, including carboxyl, hydroxyl, and amide groups, endowing its thermostable and highly negatively charged properties. The rheological analysis of the fermented whey indicates its high viscous and shear thinning (pseudoplastic non-Newtonian fluid) behavior, demonstrating the potential role of EPS-001 as a thickening and gelling agent. Besides, EPS-001 shows an excellent biosorption ability toward methylene blue (MB) and can serve as a stabilizer in the biosynthesis of selenium nanoparticles (SeNPs). Our research advances an alternative method for management of cheese whey, which may reduce its impact on the environment, and develops a novel value-added EPS for thickening, bioremediation and stabilizing nanomaterials.