The pathway proposed for lactic acid
degradation by L. buchneri includes decarboxylation of pyruvate
and formation of acetyl-CoA by a pyruvate dehydrogenase complex
(Oude Elferink et al., 2001). The reaction mechanism for this enzyme includes the uptake of one hydrogen ion per molecule of
pyruvate that is decarboxylated (Combs, 1998), which could
contribute substantially to the observed deacidification. This reaction
and the production of less acidic end products explains the rise
in pH that was correlated with lactic acid utilization. Furthermore,
this rise in pH in a commercial fermentation environment would
allow undesirable metabolic activity by a host of other organisms
that are usually controlled by low pH.