Tolerance of Lactobacillus acidophilus as micro-ecological strains by simulating gastrointestinal environment

Abstract

The resistance of Lactobacillus acidophilus as intestinal micro-ecological strains to hydrochloric acid, pepsin, bile salt, trypsin and some antibiotics by simulating gastrointestinal environment were studied in this paper. The results showed that the living bacterial number (LBN) of L. acidophilus Ind-1 and L. acidophilus Lakcid which measured by plate colony-counting method was above 107cfu/mL in MRS medium with pH 1.50-4.50 and with pepsin 0.592-1.482μg/mL after culturing at 37°C for 4h, and above 108cfu/mL at trysin14.24-72.32u/g and bile salt 0.2% (w/v). At the same time, it was shown that L. acidophilus had drug tolerance for some antibiotics, and could go through the stomach and duodenum into large intestine and survive to bring the probiotic effects into full play. © 2012 Springer-Verlag GmbH.