Lactate production via chimeric EM pathway. (A) The lactate production was performed as described in Materials and methods with glucose feeding at indicated rates. After the reaction for 1 and 2 h, lactate concentration was determined by HPLC, and yield on glucose (% mol/mol) was calculated. (B) Time course of lactate production at a glucose feeding rate of 0.01 μmol ml-1 min-1 (circle). The total concentration of NAD+ and NADH is indicated by squares. Lactate and NAD(H) concentrations with or without an additional NADH supplement (1 mM) after the initial 5-h reaction are shown by orange and green symbols, respectively.