Evaluation of the biosynthesis, structural and rheological characterization of succinoglycan obtained from a formulation composed of whole and deproteinized whey

In this study, succinoglycan was produced from whey and its rheological and structural characteristics were elucidated. Eight culture media were prepared with different ions for bioconversion of whey into succinoglycan. The formulation composed of deproteinized whey, monobasic potassium phosphate and magnesium sulfate allowed the production of 13.7 ± 0.43 g/L of succinoglycan. The apparent molar mass of succinoglycan was estimated to be 9.033 × 10⁵ g/mol and the polydispersity index was 1.044, representing the homogeneity of the sample. Monosaccharide composition of glucose and galactose for the succinoglycan produced was 6.6:1.0. The ¹H RMN analysis revealed the non-saccharide substituent content of 1.2%, 3.0% and 8.1% for acetyl, succinate and pyruvate, respectively. The rheological results showed that the apparent viscosity of the succinoglycan solutions was directly proportional to the concentration, and the solution showed pseudoplastic behavior. Dynamic frequency sweep tests identified that a concentration of 2.0% of succinoglycan is required for formation of the gel system. Temperature influenced the viscoelastic behavior of succinoglycan and revealed the melting point and reversibility of the gel. Whey was shown to be a promising carbon source for the production of succinoglycan with thickening potential and viscosity modifier.

Keywords:
succinoglycan; whey powder; rheological properties; Rhizobium radiobacter