Abstract:Eighty-nine strains of lactic acid bacteria were isolated from plants and fermented pickles in the Bama region of Guangxi. Five strains with excellent selenium-enrichment properties, Leuconostoc mesenteroides subsp. Jonggajibkimchii GXB032, Lactobacillus fermentum GXB083, Leuconostoc lactis GXB059, Weissella cibaria GXB053, and Lactobacillus brevis GXB065, were screened based on indicators such as cell density, biomass, and selenium-enrichment capacity. At a sodium selenite concentration of 10 μg/mL and treatment time of 3 h, the total selenium and organic selenium contents of all five strains exceeded 375 μg/g dry cell weight, with the conversion of organic selenium exceeding 95%. Comparisons of the activities of the probiotic strains, such as antioxidant performance, adhesion activity, acid and bile salt resistance, and gastrointestinal survival, before and after selenium enrichment treatment, revealed that the antioxidant activities of all five selenium-enriched strains showed a trend of significant increase compared with those of the non-selenium-enriched control group. Among the assessed strains, GXB083 was characterized by the highest DPPH, superoxide anion, and ABTS free radical scavenging activities of 43.64%, 19.24%, and 21.51%, respectively. The five selenium-enriched strains showed survivals exceeding 79.55%, 96%, and 82% at pH 3.0, in simulated gastric fluid, and in simulated intestinal fluid, respectively, with bile salt tolerances ranging from 42.76% to 69.77%. In addition, strain GXB053 was found to show the best self-aggregation ability (45.17%) and surface hydrophobicity (49.66%). The findings of this study indicate that the five assessed lactic acid bacteria with strong selenium-enriching capacities have excellent probiotic characteristics, providing a reference and basis for the development of potential food source selenium-enriched lactic acid bacteria.
