Optimising the production of exopolysaccharides from Pediococcus pentosaceus SSC-12 and characterizing its properties

Exopolysaccharides (EPS) derived from lactic acid bacteria are valuable biomaterials in food and healthcare industries due to their biofunctional properties. This study optimised the fermentation parameters of Pediococcus pentosaceus SSC-12, achieving a maximum EPS yield of 335.5 mg/L with an increase of 22.5% under the following conditions: glucose as carbon source, initial pH 5.5, 20 mL/L inoculum size and incubation at 34°C for 19 h. The purified EPS contained 0.55 g/g carbohydrate and exhibited a complex branched structure characterized by nuclear magnetic resonance: α-d-Glcp-(4→1)-α-d-Glcp-(3→1)-α-d-Manp-(4→3)-α-d-Manp-(1→1)-α-l-Rhap-(4→1)-β-d-Glcp-(6→4,6)-α-d-Galp-(1→ with →2)-Glcp-(1→4)-α-d-Manp-(1→1,2)-α-d-Manp-(6→4)-α-l-Arap-(1→ branches. Thermal stability analysis revealed a degradation temperature of 238°C, and scanning electron microscopy imaging showed dispersed flaky morphology of the EPS. These findings provided ideas for the study of EPS from lactic acid bacteria and theoretical bases for the application of natural active substances in food, feed and healthcare industries. • The optimum conditions for strain SSC-12 producing EPS was determined. • The yield of SSC-12 EPS under the optimum conditions increased by 22.5%. • The structure of SSC-12 EPS was characterized. • SSC-12 EPS had a dispersed flaky structure. • The SSC-12 EPS was of good thermal stability.