Exploring the physicochemical, structural, metabolic, and flavor compounds of Limosilactobacillus fermentum in fermented yogurt through comparative genomics.

Adding specific lactic acid bacteria to yogurt has been known to enhance both its benefits and flavor. However, differences among the strains of the same species present significant challenges. In this study, we constructed a phylogenetic tree of 232 Limosilactobacillus fermentum strains and selected seven strains with distinct evolutionary relationships for yogurt fermentation. L. fermentum FFJ12, which possesses more glycoside hydrolases (GH), had the highest growth rate and acid production. Conversely, L. fermentum FBJSY21_1, containing less GH, showed poor acid production. Yogurt texture might be related to amino acid synthesis. L. fermentum induced a high abundance of dibenzoyl-L-tartaric acid anhydride, leading to a wine-like flavor in yogurt. Additionally, L. fermentum upregulated citric acid and 4-acetamidobenzoic acid levels; and downregulated phenylalanine abundance. This study provided novel insights into the selection of potential probiotics for yogurt fermentation, thereby promoting the development of precision yogurt.