Diversity of isolated lactic acid bacteria in Ya'an sourdoughs and evaluation of their exopolysaccharide production characteristics

The lactic acid bacterial diversity of wheat sourdoughs collected in Ya'an city, Sichuan province was investigated by culture-dependent methods combined with 16S rRNA gene sequencing, and the exopolysaccharide (EPS) production characteristics of ropy lactic acid bacteria (LAB) strains from these sourdoughs were evaluated. Two hundred nineteen LAB strains were isolated, and genotypic characterization indicated that the isolated LAB strains included Lactobacillus plantarum (L. plantarum), L. pantheris, Leuconostoc citreum (Leu. citreum), Weissella viridescens, Leu. pseudomesenteroides, Lactococcus lactis (L. lactis), L. raffinolactis, and Leu. mesenteroides. All the isolates were found to harbor genes coding for EPS, and the yield of EPS produced by “ropy” LAB strains ranged between 2.3 and 229.5 mg/g wet cell weight. The present study enhances our knowledge about LAB diversity in Ya'an sourdoughs and provides information about the EPS-producing LAB strains in sourdough samples, which might be favorable for the application of specific LAB strains in sourdough technology.