Effect of Synthetic Flavonoids on Lactobacillus rhamnosus Aggregation and Exopolysaccharide Production

This study aimed to investigate how synthetic flavonoids influence key probiotic traits of Lactobacillus rhamnosus, particularly its exopolysaccharide (EPS) production and cell aggregation. Five methylflavone derivatives were added to the L. rhamnosus fermentation medium (200 µg/mL) under optimized conditions. EPS yield and aggregation capacity was subsequently quantified. Results indicated that flavonoid supplementation markedly enhanced EPS production, with the most active compound increased the yield more than threefold compared to the control (371 ± 7.9 mg L-¹ vs. 114.9 ± 0.3 mg L-¹). Auto-aggregation and co-aggregation with beneficial strains was also improved, while adhesion to pathogenic bacteria decreased. Conclusively, these results demonstrated that synthetic flavonoids can considerably strengthen the probiotic functionality of L. rhamnosus, offering a promising strategy to overcome its naturally low EPS productivity and improve its potential for industrial and therapeutic applications.