engleski

Probiotic approach: bile salts biotransformations by lactic acid bacteria

Bile tolerance is an essential criterion in the selction of microbial strains for probiotic use. the effects of bile salts on the survival of potential probiotic strains Lactobacillus acidophilus M92, Lactobacillus plantarum L4 and enterococcus faecium L3 were investigated using oxgall and individual bile salts (taurocholate, cholate, glycodeoycholate and deoxycholate). All of three ecamined strains have shown a satisfactory degree of tolerance against bile salts tested, especially to taurocholate. The higher resistance against taurine-conjugated ble salt relative to deconjugated and glycine-conjugated bile salts was attributed to its reaction to the stronger acidity of the former. The bile salt hydrolase (BSH) activity, determined when lactic acid bacteria grow in the presence of sodium taurocholate, may be important for bile resistance as detoxification reaction. Moreover, BSH activity was associated with steroid 7a-dehydroxylase activity for the strain L. plantarum L4 and E. faecium L3. The dehydroxylated molecule of cholic acid (deoxycholic acid) has a low solubility and its toxicity disappeared in the culture broth at modrately acidic pH as the molecule precipitated. Thr colonial and cellular morphologies may also be a valuable parameters in the selection of bile salt-resistant Lactobacillus strains for probiotic use.

bile salts biotransformations; lactic acid bacteria; probiotics

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