From genes to functions: Multifunctional probiotic properties of Lacticaseibacillus paracasei NCU215 unveiled by genomic analysis and experimental evidence

Lacticaseibacillus paracasei NCU215 was recognized for its robust probiotic activities and excellent fermentation capabilities. In the present study, whole-genome, comparative genomics analysis, and experimental validation were integrated to systematically investigate the potential functional traits of NCU215. Genomic analysis revealed that NCU215 harbors a repertoire of functional genes and is devoid of genes associated with human pathogenicity. Additionally, the metabolic pathways involved in amino acid and carbohydrate metabolism in NCU215 were computationally predicted. Based on average nucleotide identity (ANI), average amino acid identity (AAI), and core-genome phylogenetic reconstruction, the taxonomic assignment of NCU215 was revised from Lacticaseibacillus casei to Lacticaseibacillus paracasei . Comparative genomic analysis indicated that NCU215 contains higher abundance of genes associated with cell adhesion, carbohydrate metabolism, and a unique amino acid metabolic gene cluster ( cysK–ctl1–cysE ). Experimental validation confirmed that NCU215 displays a high adhesion rate of 7.86 ± 0.65% to Caco-2 cells, the ability to convert methionine to cysteine, enhanced utilization of galactose, mannose, fructooligosaccharides, and inulin, as well as bile salt hydrolase activity and a high cholesterol-lowering efficacy of 47.30 ± 2.61%. Furthermore, soymilk fermented with NCU215 exhibited a substantial reduction in volatile compounds such as hexanal and 1-octen-3-ol, while the contents of acetoin and 2,3-butanedione were notably elevated.