Dissecting Metabolic Functions and Sugar Transporters Using Genome and Transportome of Probiotic Limosilactobacillus fermentum KUB-D18

<b>Background/Objectives:</b><i>Limosilactobacillus fermentum</i> KUB-D18, a heterofermentative lactic acid bacterium with promising probiotic properties, is known for promoting gut health and nutrient absorption. Originally isolated from chicken intestines, this strain demonstrates versatile metabolic capabilities in diverse gastrointestinal environments. However, the metabolic functions and sugar transport-related genes remain largely unexplored. This study thus aimed to dissect metabolic functions and sugar transports of <i>L. fermentum</i> KUB-D18. <b>Methods:</b> Next-generation and third-generation sequencing techniques using integrative genomic platform towards transportome analysis were performed. <b>Results:</b> The complete genome, sized at 2.12 Mbps with a GC content of 51.36%, revealed 2079 protein-encoding genes, of which 1876 protein functions were annotated and identified in top categories involved in amino acids, nucleotide, energy, and carbohydrate transports and metabolisms. Comparative genes analysis identified 50 core and 12 strain-specific genes linked to probiotic properties, e.g., acid resistances and bile tolerances, antioxidant functions, or anti-inflammatory properties. Further, sugar transportome analysis uncovered 57 transporter genes, demonstrating diverse carbon utilization and phosphotransferase (PTS) systems, corroborated by API 50 CHL test results for carbohydrate metabolism profile. <b>Conclusions:</b> These findings enhance the comprehensive metabolic understanding of <i>L. fermentum</i> KUB-D18, supporting its industrial potential and applications in engineered probiotics.