Study on a galactose decomposition strain of Lactiplantibacillus plantarum MWLp-4 from human milk: Safety evaluating and key genes analysis of potential probiotic function

Galactose intolerance, associated with bloating and abdominal pain, is similar to lactose intolerance. Congenital galactose malabsorption in a child can lead to severe diarrhea. To avoid the consequences of galactose malabsorption, we obtained a galactose decomposition strain of Lactiplantibacillus plantarum MWLp-4 from human milk. Importantly, this strain had almost overlapping dynamics of galactose and lactose utilization, showing a great galactose catabolic ability. In this paper, we studied safety evaluation including hemolysis test, drug sensitivity test, and determination of amine in vitro of L. plantarum MWLp-4. In addition, we evaluated the probiotic function such as antimicrobial properties, adhesion, acid resistance, and bile salt resistance, etc. Meanwhile, we have analyzed the key genes on function and safety. As a conclusion, this strain possess great safety and probiotic function. The genes related to galactose metabolism, bacteriocin synthesis, surface protein synthesis, bile salt hydrolysis and stress response are found in L. plantarum MWLp-4. Analysis of the consistency of the phenotype with its genotype via whole genome sequencing showed that the phenotype of its physiological function is due to the large number of related genes existing in it. Therefore, this study would provide potential degrading galactose probiotics for producing special functional food.