Probiotic properties of Weissella strains isolated from human faeces

Three Weissella confusa and five Weissella cibaria strains were previously isolated from human faeces and their potential as probiotics was examined in this work. Resistance to low pHs (pH 2.0 and 3.0) and 0.3% bile salt were examined. Enzyme activities, susceptibilities to heat treatment and various antibiotics, and adhesion capacities to Caco-2 cells were also examined. All Weissella strains were killed when exposed to pH 2.0 for 2 h but survived at pH 3.0 with different survival ratios. W. confusa 31 survived best (20.2%) and W. confusa 31 was also quite resistant against 0.3% bile salt (128.8%). All strains except one grew well at temperature between 15 and 45 °C and all strains grew in the presence of 6.5% NaCl. W. confusa 20 showed the highest β-galactosidase activity (527.3 ± 23.66 unit/mg protein) and W. cibaria 31 had the highest β-glucosidase activity (115.12 ± 5.3 unit/mg protein) in MRS broth. All strains adhered to Caco-2 cells better than Lactobacillus rhamnosus GG and W. confusa 20 was the best adhesive strain (85 CFU/cell). These results show that some strains such as W. confusa 31 and W. confusa 20 are fully qualified as probiotics and deserve further application studies.