Effect of oxygen and uracil on growth and energetic parameters of strains D39 and R6^a.

a<p>D39 and R6 were grown in CDM containing 61±1 mM glucose, with pH-controlled at 6.5, at 37°C, under different atmospheres (semi-aerobic, anaerobic or aerobic); to test the effect of uracil (U) on growth of both strains under semi-aerobic conditions, the nucleobase was added to a final concentration of 30 mg l⁻¹.</p>b<p>Growth phase at which samples were harvested for substrate and fermentation product analysis by HPLC; see text for details.</p>c<p>Product yields, [End-product, mM]/[Glucose consumed, mM].</p>d<p>Blank cells, negative yields were found for these conditions (cells used pyruvate from the medium).</p>e<p>q_s^max (substrate consumption rate) was estimated from a first-order derivative of a polynomial fit of the measured substrate consumption time series.</p>f<p>Carbon balance is the percentage of carbon in metabolized glucose that is recovered in the fermentation products (lactate, formate, acetate and ethanol) and pyruvate.</p><p>Dry weight (DW) was used as a measure of cell mass. BDL, below detection limit of the HPLC technique; ND, not determined.</p><p>Values of at least two independent experiments were averaged and errors are reported as ± SD.