Gastrointestinal tolerance and intestinal adhesion of Lactobacillus pentosus isolated from a traditional cheese in Northwestern China
We studied the gastrointestinal tolerance and intestinal adhesion of two potential probiotic Lactobacillus pentosusstrains IND1 and IND3 isolated from traditional cheese product in Northwestern China. The gastrointestinal tolerance was tested insimulated gastric juice, bile salts and intestinal solution. The adhesive ability was evaluated by using Caco-2 cell lines. Viability ofboth strains was above 90 percent in simulated gastric juice (pH 2.5), 80 percent in bile salt and 90 percent in intestinal solution.Growth conditions such as growth stage, fermentation pH, temperature and living state affected the adhesion of bacteria cells.A pH range from 4 to 6 favoured their adhesion. No big difference in adhesion was found between cultivable and thermalinactivated cells. The good adhesion ability of the two L. pentosus strains occurred when the growth stage of bacterial cellsreached 26 h at pH 4.0 and 37°C. The adhesion of L. pentosus IND1and IND3 decreased significantly due to the presences oftrypsin and proteinase K, which implied that the surface protein of the two L. pentosus strains has been involved in the adhesiveprocess. However, removal of S-layer protein from cell surface did not affect adhesion meaning that S-layer protein from the twoL. pentosus strains was not involved in the adhesion. The tested L. pentosus strains would be promising as potential probiotics.