Phenotypic and Genotypic Identification of Exopolysaccharide-Producing Lactic Acid Bacteria from Traditional Dairy Products of Guilan Province

Numerous lactic acid bacteria (LAB) possess the ability to synthesize exopolysaccharides (EPS), which may be either cell-associated or liberated into the culture medium. This chemical has significant therapeutic qualities and is regarded as a crucial addition in the food sector. This research aimed to isolate and identify lactic acid bacteria strains capable of producing exopolysaccharides from typical dairy products. LABs were isolated with MRS broth medium. Screening for EPS-producing bacteria was conducted on the identical medium subsequent to the incorporation of 10% (w/v) sucrose and 0.5% (w/v) calcium carbonate. The bacteria responsible for production were identified by molecular techniques, specifically 16S rRNA, while the quantitative examination of polysaccharides was conducted by assessing their dry weight. Seven of the 19 isolates from traditional dairy products in Gilan province were identified as EPS producers. The strain exhibiting the highest production rate, 1.832±12.881 g/L, was identified as the most effective producer. Within 24 hours, Lactobacillus plantarum generated 923 mg of polysaccharide per liter of culture, marking the highest yield. The L. plantarum isolate obtained in this work is proposed as an effective and appropriate source for semi-industrial and industrial exopolysaccharide production.