Abstract: The surface characteristics and adhesion properties of Lacticaseibacillus paracasei ZY-1, derived from Tibetan kefir grains, and L. paracasei S-NA5 and S-NB, isolated from Xinjiang traditional fermented milk, were evaluated in vitro, and whole genome sequencing was performed to compare the difference among adhesion-related genes in the three strains. The gastrointestinal tolerance and adhesion properties of L. paracasei S-NB to Caco-2 cells were superior to those of S-NA5 and ZY-1. Moreover, two exopolysaccharide (EPS) synthesis gene clusters were found in each strain, and the EPS cluster 1 of strain ZY-1 differed significantly from that of S-NA5 and S-NB. Meanwhile, genes involved in lipoteichoic acid (LTA) synthesis and related domains of protein adhesins were predicted. The secondary structure prediction of the products encoded by the adhesion protein genes in S-NB showed that the secondary structure of 11 adhesion proteins was dominated by α-helix and random coil. Additionally, the complete metabolic pathways of lactose, galactose, fructi-oligosaccharide, inulin and human milk oligosaccharides were found in the three strains, which were all highly conserved.

Key words: Lacticaseibacillus paracasei; intestinal adhesion; genome sequencing; adhesin; carbohydrate metabolism pathway