Screening and Identification of New Types of Exopolysaccharides-Producing Lactic Acid in the Inner Mongolia Dairy Products

Exopolysaccharides (EPS) is a type of polysaccharide produced by lactic acid bacteria (LAB) that can be directly used in foods to make the products more excellent. Therefore, batch studies were performed to explore the effect of different LAB on the production of EPS and antioxidant activity. Five strains with high EPS yield and antioxidant activity were screened out from 66 strains isolated from Tibetan dairy products. The results show that EPS produntion of the five strains (B55, B62, B30, 7830 and K2) were 110.66, 145.48, 132.78, 122.11 and 111.72 mg·L⁻¹, respectively, and they have a higher DPPH free radical scavenging activity (56.29, 66.43, 62.94, 68.71, 61.87%). Five LAB strains were identified and classified based on screening, purification and 16S rDNA sequences. Molecular characterization based on partial sequence 16S rDNA homology confirmed the initial identification as Lactobacillus fermentum (B55, B62), Lactobacillus plantarum (7830), Pediococcus acidilactici (B30) and Lactobacillus helveticus (K2).