Screening and application of high-folate-producing lactic acid bacteria in yogurt products

<h2>ABSTRACT</h2> Folate is a vital micronutrient that cannot be endogenously produced by the human body, necessitating dietary intake to support critical physiological functions. The objectives of this research were to isolate and select lactic acid bacteria (LAB) strains with high folate-producing capabilities, evaluate their probiotic properties and safety, and optimize fermentation conditions for high-folate dairy products. <i>Lactiplantibacillus plantarum</i> ZJUIDS16 (ZJUIDS16), isolated from a laboratory strain collection, produced 27.16 μg/mL of folate. Whole-genome sequencing revealed its folate biosynthesis pathways, and stress resistance tests confirmed its probiotic characteristics and safety. A Box-Behnken response surface design was applied to optimize key conditions, including pH, temperature, inoculum size, and para-aminobenzoic acid (pABA), increasing folate production to 34.72 μg/mL. In fermented milk, folate content reached 56.18 μg/mL, surpassing traditional fermentation agents. ZJUIDS16 enhanced both physicochemical and sensory qualities of dairy products. ZJUIDS16 was selected based on its overall superior performance, including high folate production, the presence of folate biosynthesis-related genes, and favorable probiotic characteristics. This demonstrates the potential of <i>L. plantarum</i> ZJUIDS16 for future dairy applications.