The production enhancement of Weissella confusa P2 exopolysaccharide and its partial biological activity

Exopolysaccharide (EPS) from lactic acid bacteria is of interest for its multifunctional properties, but low yield limits industrial application. This study optimized EPS production by Weissella confusa P2 using response surface methodology (RSM). Plackett-Burman (PB) design identified significant factors (sucrose, sodium acetate, and K2HPO4), followed by steepest ascent approach to approximate optimal levels, with final optimization via central composite design (CCD). Under the optimized conditions (77.42 g/L sucrose, 3.42 g/L sodium acetate, 1.76 g/L K2HPO4, 12 g/L peptone, 12 g/L beef extract, 6 g/L yeast extract, 3 g/L ammonium citrate, 0.15%Tween-80, 0.2 g/L MgSO4 and initial pH value 6.5), EPS yield increased 1.60-fold to 49.93 g/L. W. confusa P2 EPS exhibited significant antioxidant activity, with scavenging rates of 40.2 ± 0.02% (DPPH), 30.2 ± 0.01% (ABTS), 45.6 ± 0.03% (·OH), and 40.7 ± 0.03% (H2O2), and a reducing power of 0.24 ± 0.03 (OD700 nm) at 5 mg/mL. Compared to commercial prebiotics, the EPS significantly stimulated the growth of probiotics, including Bifidobacterium lactis Bi-OA 07, Lactobacillus rhamnosus CICC 21773, and Lactobacillus casei HDS-01. Furthermore, the EPS induced a concentration-dependent coagulation in sucrose-supplemented skim milk. These results highlight the potential of W. confusa P2 EPS for food industry applications.