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

BUSTOS AY, SAAVEDRA L, DE VALDEZ GF, RAYA RR, TARANTO MP.

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 lactic acid bacteria with and without ability to hydrolyze bile salts (BSH[+] and BSH[-] strains, respectively) was evaluated. BSH(+) strains showed a gradual increase in the pHin following the addition of conjugated BA; this behavior was more pronounced with GDCA than with TDCA may be due to the higher affinity of BSH for the glyco-conjugates acids. Conversely, the BSH(-) strains showed a decrease in internal pH probably as a consequence of weak acid accumulation. As expected, a decrease in the cytoplasmatic pH affected the cell survival in this last group of strains, while the BSH(+) strains were more resistant to the toxic effect of BA. PURPOSE OF WORK: To evaluate bile salt hydrolase activities, changes in the internal pH and cell survival to bile acids in lactic acid bacteria to establish the relationship between these parameters. Appl Microbiol Biotechnol. 2012 Oct;96(1):299-300. Erratum to: Appl Microbiol Biotechnol DOI 10.1007/s00253-012-3945-z The published version of this article unfortunately contains mistakes. Tables 1 and 2 have error numbers; the standard deviation (SD) values are higher than the real ones as a number 3 was added incorrectly at the beginning of each SD value in all cases, except for the SD corresponding to ?Mol 3 %, 37 °C? in Table 1, which is fine.