Figure 1

Growth, nutrient consumption and ethanol accumulation during alcoholic fermentation carried out under different nitrogen availability conditions. Growth curves and fermentation performance of S. cerevisiae PYCC 4072 were followed during 144 h of incubation at 20°C, by determining the concentrations of: (A) colony forming units (CFU mL^-1), (B) ammonium, (C) glucose and (D) ethanol in the fermentation broth. Yeast cells were cultivated in synthetic basal grape juice medium with 200 g L^-1 glucose and different nitrogen (N) concentrations leading to: i) complete fermentation (CF) [320 mg L^-1 N] (○); ii) nitrogen-limited fermentation (LF) [90 mg L^-1 N] (□); iii) nitrogen-limited fermentation LF followed by refed with ammonium after nitrogen exhaustion (RF) [90 + 230 mg L^-1 N] (▴). The arrow indicates the time of nitrogen supplementation in RF.