Abstract:An exopolysaccharides（EPS）-producing strain TH21-44 was identified based on the morphological observation，physiological and biochemical tests，and 16S rRNA gene-based phylogenetic analysis.Furthermore，the fermentation conditions of the strain for the production of EPS were optimized by single-factor and response surface methods，and the emulsification performance of the EPS was evaluated.The strain TH21-44 was identified as Paracoccus sp.The optimal fermentation conditions for EPS production were pH7.1，inoculum size of 6.1%，temperature of 28 ℃，glucose of 7.2 g/L，yeast extract of 3.0 g/L，K2HPO4·3H2O of 0.3 g/L，MgSO4·7H2O of 0.05 g/L，and sodium pyruvate of 0.3 g/L.Under these conditions，the EPS yield was 188.89 μg/mL，which was 3.18 times as high as that of before optimization.The produced EPS maintained 69.62% emulsification capacity for sunflower oil after 24 h，demonstrating the emulsification performance superior to Tween 80.The findings provide the bacterial strain resources and theoretical references for the development and application of microbial exopolysaccharides.