FIG. 3.

Kinetics of pyruvate degradation and product formation by resting cells of P. aeruginosa in 100 mM phosphate buffer (pH 7.4). The cells were grown for 21 h in OS minimal medium with 50 mM nitrate as electron acceptor and 10 mM gluconate-20 mM pyruvate as carbon source under oxygen limitation and then were harvested and washed in phosphate buffer. Finally, the cell suspensions (OD₅₇₈ between 8 and 9) of bacteria were incubated under anoxic conditions with the addition of 50 mM arginine (A), 50 mM nitrate (B), or without further additions (C). Pyruvate (•), lactate (□), acetate (▿), and succinate (▵) were detected by HPLC analysis of the supernatant as described in Materials and Methods. Graphs represent the results of three independent experiments; standard deviations were below 7% for the determined pyruvate, lactate, and acetate concentrations and below 15% for the already low succinate concentrations.