Potential probiotic characterization of lactic acid bacteria isolated from Duimaj, an Iranian traditional snack food, using biochemical, molecular and computational approaches

The aim of this study was isolation and identification of lactic acid bacteria from Duimaj (an Iranian traditional snack food) and in vitro characterization of probiotic features. In total, thirty presumptive LAB colonies were surveyed, of which 22 exhibited high rates of survival in artificial gastrointestinal fluids, which were found to belong to Lactobacillus, Enterococcus, and Pediococcus genera based on 16 S-rRNA gene sequence. The selected strains had strong antagonistic effects, with auto-aggregation abilities ranging from 26.52 to 81.50% and coaggregation capacity up to 88.33 and 80.14% with E. coli and S. aureus, respectively. Moreover, the cell surface hydrophobicity of strains ranged from 31.06 to 85.62%. Results indicated that nine isolated LAB harbored the cholesterol assimilation rates greater than 30%. Moreover, none of the selected strains showed hemolytic activity. Among the isolates, five strains were negative for all nine tested virulent genes, and exhibited favorable adhesion percentage to human intestinal epithelial cells ranging from 31.76 to 52.37. Hence, naturally occurring Lactiplantibacillus plantarum and Lactiplantibacillus pentosus isolated from Duimaj were proposed as suitable probiotic candidates for use in functional foods.