The production enhancement of <i>Weissella confusa</i> 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 <i>Weissella confusa</i> 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. <i>W. confusa</i> 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 (OD_{700 nm}) at 5 mg/mL. Compared to commercial prebiotics, the EPS significantly stimulated the growth of probiotics, including <i>Bifidobacterium lactis</i> Bi-OA 07, <i>Lactobacillus rhamnosus</i> CICC 21773, and <i>Lactobacillus casei</i> HDS-01. Furthermore, the EPS induced a concentration-dependent coagulation in sucrose-supplemented skim milk. These results highlight the potential of <i>W. confusa</i> P2 EPS for food industry applications.