Effect of folA gene in human breast milk-derived Limosilactobacillus reuteri on its folate biosynthesis

Folate supplementation is crucial for the human body, and the chemically synthesized folic acid might have undesirable side effects. The use of molecular breeding methods to modify the genes related to the biosynthesis of folate by probiotics to increase folate production is currently a focus of research. In this study, the folate-producing strain of B1-28 was isolated from human breast milk, and the difference between B1-28 and gene deletion strain was investigated by phenotyping, probiotic evaluation, metabolism and transcriptome analysis. The results showed that the folate producted by the was 2-3 folds that of the B1-28. Scanning electron microscope showed that had rougher surface, and the acid-producing capacity ( = 0.0008) and adhesion properties ( = 0.0096) were significantly enhanced than B1-28. Transcriptomic analysis revealed that differentially expressed genes were mainly involved in three pathways, among which the biosynthesis of ribosome and aminoacyl-tRNA occurred in the key metabolic pathways. Metabolomics analysis showed that affected 5 metabolic pathways, involving 89 different metabolites. In conclusion, the editing of a key gene of in folate biosynthesis pathway provides a feasible pathway to improve folate biosynthesis in breast milk-derived probiotics.