Time courses obtained by <i>in vivo</i> NMR during glucose metabolism in <i>L. lactis</i>.

<p>A, B, C and D: time courses obtained during the metabolism of [1-¹³C] glucose in non-growing cells of <i>L. lactis</i> as monitored online by <i>in vivo </i>¹³C-NMR. E and F: biochemical parameters determined during the metabolism of 40 mM glucose in <i>L. lactis</i> MG1363 as monitored online by <i>in vivo </i>³¹P-NMR. The experiments were carried out at 30 ^°C, under anaerobic conditions and pH controlled at 6.5 (orange diamonds), 5.5 (black diamonds), 5.1 (blue diamonds) and 4.8 (green diamonds). (A) Kinetics of [1-¹³C] glucose (40 mM) consumption, (B) extracellular pool of lactic acid, (C) pools of FBP (fructose 1,6-bisphosphate), (D) profiles of intracellular lactic acid, (E) profiles of intracellular P_i, and (F) intracellular pH. The time points for glucose exhaustion are indicated by vertical dashed lines (graph A, B, C, D and E). The horizontal lines in graph F represent the constant values at which the extracellular pH was controlled. The lack of information on intra and extracellular concentrations of lactic acid at pH 6.5 is due to severe overlap of the lactic acid resonances at this pH and consequent large uncertainty in the measurements of individual areas. Each experiment was performed at least twice with good reproducibility.