Effect of Functional Galactooligosaccharide on Metabolism and Antibacterial Activity of Lactiplantibacillus plantarum ZDY2013

To investigate the effects of galactooligosaccharides (GOS), a prebiotic substance, on the metabolism and adhesion ability of Lactiplantibacillus plantarum ZDY2013, as well as its inhibitory effect on the adhesion of Bacillus cereus HN001, functional GOS was used to prepare modified culture media at full and half concentrations. The metabolism of strains, the antibacterial activity in a co-culture system, and adhesion inhibition in an intestinal epithelial cell model were evaluated. The results showed that the viable cell count of L. plantarum ZDY2013 could reach 9.5 lg CFU/mL when cultured with 2.0% GOS for 24 h. However, this GOS was not a sugar source for this strain. In the co-culture system, GOS facilitated the metabolism of L. plantarum and subsequently inhibited the growth of B. cereus. The inhibition zone produced by L. plantarum metabolites against B. cereus reached a diameter of 17.93±0.64 mm. In addition, after metabolism in the modified culture medium, L. plantarum exhibited self-aggregation exceeding 80% and hydrophobicity at 73%, which were higher than those of B. cereus. Furthermore, even after treatment with 5 mol/L LiCl and an 80 ℃ water bath, it still inhibited B. cereus from adhering to intestinal epithelial cells with an inhibition rates of 60% and 40%, respectively. Taken together, the functional GOS could selectively promote the metabolism of L. plantarum ZDY2013 and further inhibit B. cereus HN001 in the co-culture systems and cell model.