Acid tolerance and endogenous acid production by oral bifidobacteria

This study focused on the responses of oral bifidobacteria to acidification and their ability of endogenous acid production without an extracellular energy source. In the absence of exogenous glucose, the viability and the stability of intracellular pH of bifidobacteria were maintained at acidic pH, besides bifidobacteria continued to produce acid even at acidic pH. The continuous acid production from endogenous energy source in acidic environment may contribute to acid tolerance of bifidobacteria in the absence of extracellular energy source.