Comparison of the biological activity of different probiotic strains under aerobic and anaerobic conditions.

Lactic acid bacteria (LAB) are widely recognized as probiotics due to their health-promoting properties. Some strains can perform both aerobic metabolism and fermentation, which may influence their biological functions. This study investigated the impact of Lactobacilli metabolism on three specific biological functions: anti-inflammatory, antioxidant, and antimicrobial effects, across eleven LAB strains. To this end, growth profiles under aerobic and anaerobic condition were monitored by turbidity. Antimicrobial potential of the probiotic strains was assessed against Staphylococcus aureus and Listeria monocytogenes using extracellular or intracellular fractions of each probiotic previously cultured aerobically or anaerobically. Antioxidant capacity was measured indirectly through a colorimetric assay of iron II. Then anti-inflammatory potential was evaluated in HT29 cells by cytokine quantification. For the first time, this article highlights that all strains studied enhanced their biological activity through fermentative metabolism. As expected, most strains inhibited L. monocytogenes. Among them, Lactobacillus delbruekii subsp. lactis showed the highest biological activity, followed by Lacticaseibacillus rhamnosus and Limosilactobacillus mucosae. These strains also reduced inflammation by 50% and exhibited a high antioxidant capacity (585 ± 68 µmol/L). These results demonstrate interesting characteristics of probiotic strains, particularly under fermentative conditions. Their integration into probiotic formulation may provide valuable nutritional strategies to improve gut health and overall well-being.