Relationships between fatty acid composition and bile tolerance in lactobacillus isolates from plants and from non-plant materials

Abstract

Twenty plant-derived and 18 non-plant-derived strains of Lactobacillus casei were compared for their growth in tryptone – yeast extract – glucose broth containing 0.3% bile by measuring absorbance at a wavelength of 620 nm after 24 h of incubation at 37 °C. Bile tolerance — a fundamental probiotic property — was calculated by dividing the experimental data by control values (growth without bile). We found that bile tolerance was strain specific but that the average bile tolerance of the plant-derived strains was significantly (P < 0.05) lower than that of the non-plant-derived strains tested. All tested strains could not deconjugate sodium taurocholate, indicating that the difference in bile tolerance was not due to the ability to deconjugate bile. The fatty acid compositions of the test strains with and without exposure to 0.3% bile were investigated, and a statistical correlation analysis between these compositions and their bile tolerance was conducted. The fatty acids correlated with bile tolerance differed between plant and non-plant lactobacilli. This is the first report to show that the origin (i.e., growth environment) of lactobacilli affects their fatty acid composition, which in turn, appears to be related to their bile tolerance.