Lactate degradation by a strain of Neisseria isolated from human dental plaque.

An oral Neisseria strain Ne-15 degraded lactate under aerobic conditions. Most of the lactate, both the l(+) and d(?) forms, was converted via pyruvate to acetate, and it seems that ATP may be generated through this pathway. Part of the lactate was converted to acetate directly. A small portion of pyruvate was further metabolized by the way of the citric acid cycle after CO₂ fixation or after conversion to acetyl-CoA, and was utilized for synthesis of cell components. The addition of the Neisseria in a mixed incubation with Streptococcus murans caused no change in glucose utilization but a reduced lactate concentration.