[Mechanism of the variation of the acetate/lactate/ratio during glucose fermentation by bifidobacteria (author's transl)].

It is demonstrated that most strains of bifidobacteria form much more acetate and less lactic acid from glucose than is to be expected according to the breakdown of glucose via the "bifidoshunt". The analysis of isotope distribution among the fermentation products of glucose labeled in different positions showed that the excess of acetate is the result of the phosphoroclastic splitting of a part of the pyruvate arising from carbons 4, 5, and 6 of glucose. In addition to acetate (carbons 5 and 6), formate is formed from carbon 4 and some acetate is reduced to ethanol. The formation of "extra" acetate occurs mainly during the log phase and is less pronounced in resting cells. The extent of the phosphoroclastic splitting of pyruvate varies considerably among different strains even among those from the same species.