Based on whole genome sequencing and metabolomics analysis the safety and probiotic characteristics of Lacticaseibacillus paracasei 36 isolated from Chinese fermented vegetables

Lacticaseibacillus paracasei is a facultative anaerobic bacterium, which is classified as a Generally Recognized as Safe (GRAS) microorganism by the Food and Drug Administration (FDA). In this study, we reported the whole genome sequence of Lacticaseibacillus paracasei 36 (L. paracasei 36), which consisted of a circular chromosome and three circular plasmids, with a total length of 3,166,237 bp and an average G + C content of 46.21%. Based on genetic analyses of production of harmful metabolites, virulence factors, and antibiotic resistance, as well as in vivo safety tests conducted with L. paracasei 36, we postulated that L. paracasei 36 was safe. The stress-response genes of L. paracasei 36 indicated that it exhibited robust tolerance to the gastrointestinal tract, temperature, and osmotic pressure. Additionally, it demonstrated high capacities for colonization and adhesion, as well as notable antioxidant activity. The metabolomic results of the L. paracasei 36 fermentation supernatant demonstrated that metabolites were mainly concentrated in amino acid metabolism and biosynthesis of other secondary metabolites, and there was a notable increase in proclavaminic acid and lactic acid. In conclusion, L. paracasei 36 possessed favorable probiotic characteristics and safety, thereby establishing it as a probiotic candidate with considerable potential.