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Table 1 Concentration of compounds and calculated parameters on the steady state of aerated (at 0.02 vvm) or non-aerated S. cerevisiae continuous cultures, fed with sterilized (SM) or non-sterilized medium (NSM)

From: Improvement on the productivity of continuous tequila fermentation by Saccharomyces cerevisiae of Agave tequilana juice with supplementation of yeast extract and aeration

Compound (g L−1) Aeration and dilution rates (D)
0 vvm and 0.08 h−1 0.02 vvm and 0.08 h−1
SM NSM SM NSM
A (Non-supplemented with yeast extract)
Biomass 5.90 ± 0.21 4.93 ± 0.42 7.33 ± 0.29 6.83 ± 0.72
Ethanol 38.25 ± 0.84 37.48 ± 1.61 41.87 ± 0.62 39.97 ± 0.04
R sugars 14.46 ± 0.52 26.52 ± 0.33 4.73 ± 0.57 12.18 ± 1.63
Fructose 4.27 ± 1.23 26.27 ± 3.35 9.56 ± 2.33 10.76 ± 1.16
Glucose 2.17 ± 0.37 0.90 ± 0.14 2.62 ± 0.10 0.39 ± 0.01
Succinic acid 0.16 ± 0.01 0.06 ± 0.08 0.21 ± 0.09 0.12 ± 0.00
Glycerol 4.48 ± 0.38 3.08 ± 0.23 7.00 ± 0.11 4.44 ± 0.14
Diacetyl nd nd nd nd
Acetic acid nd nd nd nd
Acetoin 0.33 ± 0.12 nd nd 0.18 ± 0.03
NH4 + 1.80 ± 0.22 1.55 ± 0.17 1.17 ± 0.09 0.89 ± 0.05
YX/S 0.069 ± 0.002 0.067 ± 0.005 0.077 ± 0.003 0.078 ± 0.007
YP/S 0.447 ± 0.007 0.510 ± 0.020 0.439 ± 0.004 0.455 ± 0.008
PP 3.060 ± 0.067 2.998 ± 0.129 3.350 ± 0.050 3.198 ± 0.003
pH 3.0 ± 0.1 2.9 ± 0.3 2.8 ± 0.1 2.7 ± 0.3
  1. Medium contained agave juice (adjusted at 100 g L−1 of R sugars), ammonium sulfate (1 g L−1) and ammonium phosphate monobasic (4 g L−1). YX/S is biomass yield (g g−1). YP/S is ethanol yield (g g−1). PP is ethanol productivity [g (Lh)−1]. Values are the means ± standard deviations (n = 3)
  2. R sugars are Reducing sugars, nd compound not detected under the analysis conditions
  3. aExperiments using media supplemented with yeast extract were performed at higher D, because this supplementation allowed this increase without losing stability in the continuous culture
Compound (g L−1) Aeration and dilution rates (D)
0 vvm and 0.10 h−1 0.02 vvm and 0.12 h−1
SM NSM SM NSM
B (Supplemented with yeast extract)a
Biomass 6.57 ± 0.68 6.42 ± 0.23 8.16 ± 0.70 8.28 ± 0.90
Ethanol 42.95 ± 2.86 46.22 ± 3.20 45.11 ± 0.49 46.92 ± 1.87
R sugars 5.86 ± 0.48 6.60 ± 0.25 7.53 ± 0.89 7.23 ± 0.09
Fructose 3.56 ± 0.19 5.03 ± 0.32 2.91 ± 0.55 6.63 ± 0.04
Glucose 0.06 ± 0.04 0.41 ± 0.19 nd 0.57 ± 0.00
Succinic acid 0.08 ± 0.06 0.14 ± 0.02 0.08 ± 0.06 0.12 ± 0.04
Glycerol 2.76 ± 0.17 3.93 ± 0.17 3.00 ± 0.08 3.14 ± 0.06
Diacetyl nd nd nd nd
Acetic acid nd nd nd nd
Acetoin nd nd nd nd
NH4 + 1.16 ± 0.12 1.59 ± 0.51 0.94 ± 0.05 0.77 ± 0.13
YX/S 0.070 ± 0.007 0.069 ± 0.002 0.088 ± 0.007 0.089 ± 0.010
YP/S 0.456 ± 0.028 0.495 ± 0.033 0.488 ± 0.001 0.506 ± 0.020
PP 4.295 ± 0.286 4.622 ± 0.320 5.413 ± 0.059 5.630 ± 0.224
pH 2.8 ± 0.3 2.7 ± 0.1 2.6 ± 0.2 2.6 ± 0.3
  1. Medium contained agave juice (adjusted at 100 g L−1 of R sugars), ammonium sulfate (1 g L−1) and ammonium phosphate monobasic (4 g L−1). YX/S is biomass yield (g g−1). YP/S is ethanol yield (g g−1). PP is ethanol productivity [g (Lh)−1]. Values are the means ± standard deviations (n = 3)
  2. R sugars are Reducing sugars, nd compound not detected under the analysis conditions
  3. aExperiments using media supplemented with yeast extract were performed at higher D, because this supplementation allowed this increase without losing stability in the continuous culture