Relationship between bile salt hydrolase activity, changes in the internal pH and tolerance to bile acids in lactic acid bacteria

BUSTOS, ANA YANINA; LUCILA SAAVEDRA; FONT DE VALDEZ, GRACIELA; RAYA, RAUL; TARANTO, MARIA PIA

BIOTECHNOLOGY LETTERS

SPRINGER

Lugar: Berlin; Año: 2012 vol. 34 p. 1511 - 1518

0141-5492

Abstract The effect of the conjugated bile acid (BA)on the microbial internal pH (pHin) values in lacticacid bacteria with and without ability to hydrolyze bilesalts (BSH[?] and BSH[-] strains, respectively) wasevaluated. BSH(?) strains showed a gradual increasein the pHin following the addition of conjugated BA;this behavior was more pronounced with GDCA thanwith TDCA may be due to the higher affinity of BSHfor the glyco-conjugates acids. Conversely, theBSH(-) strains showed a decrease in internal pHprobably as a consequence of weak acid accumulation.As expected, a decrease in the cytoplasmatic pHaffected the cell survival in this last group of strains,while the BSH(?) strains were more resistant to thetoxic effect of BA.Purpose of work To evaluate bile salt hydrolaseactivities, changes in the internal pH and cell survivalto bile acids in lactic acid bacteria to establish therelationship between these parameters