Weissella confusa XG-3 EPS: production intensification by co-culturing with Candida shehatae and partial characterization

Previous studies have shown that co-culture methods can enhance exopolysaccharide production, no studies have reported this enhancement in co-cultures between Weissella confusa and Candida shehatae. This study developed an efficient co-culture system combining W. confusa XG-3 and C. shehatae (1:1 ratio), and employed response surface methodology to optimize both exopolysaccharide yield and properties. The initial co-culture produced 56.82 ± 0.12 g/L exopolysaccharide, a 1.63-fold increase over single culture. Optimization (sucrose: 105.97 g/L; yeast extract: 5.81 g/L; peptone: 6.24 g/L) further increased the yield to 115.66 g/L, a 2.04-fold improvement. The co-cultured exopolysaccharide had high water solubility (60.45 ± 0.70%) and water holding capacity (614.74 ± 9.26%). The co-cultured EPS showed significant antioxidant activity. At 5 mg/mL, the scavenging rates of ABTS, DPPH, hydroxyl, superoxide, H₂O₂ and total reducing power reached the highest 52.22 ± 0.47%, 50.79 ± 2.86%, 55.80 ± 2.56%, 36.05 ± 2.07%, 66.85 ± 0.30%, and 0.39 ± 0.01. It also had a superior effect on the proliferation of several probiotics compared with commercial prebiotics and exhibited high thermostability with a degradation threshold at 292.5 °C. These results demonstrate a novel, scalable strategy for producing multifunctional EPS with broad applications in the food industry.