Phenotypic and genomic characterization of <i>Levilactobacillus brevis</i> YT108: a potential probiotic strain capable of metabolizing xylo-oligosaccharides

Levilactobacillus brevis YT108, identified for its ability to metabolize prebiotic xylo-oligosaccharides (XOS), emerges as a candidate for probiotic use in synbiotic food formulations. This study aimed to investigate the metabolic and genomic traits associated with XOS metabolism in YT108 and to assess its probiotic attributes through whole genome sequencing and in vitro assays. Strain YT108 exhibited robust growth kinetics on XOS as the sole carbon source, with a growth profile comparable to that on glucose, achieving a pH reduction to 4.68 and an OD600nm of 1.603 after 48 h. Three key gene clusters (xylCDEPFRT, xylHTG, and xylABT) and key enzymes (1,4-β-xylosidase) were identified as potentially involved in XOS metabolism. In vitro assays confirmed the strain's remarkable physiological properties, including tolerance to acid, bile, heat, and NaCl, as well as resistance to simulated gastrointestinal juices and antioxidant capacity. Furthermore, strain YT108 was sensitive to five commonly used antibiotics and lacked transferable resistance genes. Taken together, these results highlight the potential of L. brevis YT108 as a probiotic candidate with beneficial traits for XOS utilization, suggesting its promising application in the formulation of next-generation synbiotic products.