Table 1.
Product yields of xylose and glucose fermentation in a chemostat by mixed cultures, at pH 8
| Xylose 0.133 Cmol/L | Glucose 0.133 Cmol/L | Xylose 0.333 Cmol/L | |
|---|---|---|---|
| Dilution rate (h−1) | 0.128 ± 0.004 | 0.128 ± 0.004 | 0.134 ± 0.004 |
| Biomass yield (Cmol/Cmol) | 0.16 ± 0.01 | 0.21 ± 0.01 | 0.13 ± 0.01 |
| Product yields (Cmol/Cmol S) | |||
| Acetate | 0.18 ± 0.01 | 0.16 ± 0.02 | 0.22 ± 0.01 |
| Butyrate | 0.46 ± 0.02 | 0.30 ± 0.04 | 0.07 ± 0.01 |
| Ethanol | 0.017 ± 0.004 | 0.08 ± 0.01 | 0.23 ± 0.01 |
| Formate | 0.20 ± 0.02 | 0.22 ± 0.01 | 0.18 ± 0.01 |
| H2 (mol/Cmol S) | 0.13 ± 0.01 | 0.05 ± 0.01 | 0.06 ± 0.01 |
| H2 + Formate (mol/Cmol S) | 0.33 ± 0.02 | 0.27 ± 0.01 | 0.24 ± 0.01 |
| Acetyl-CoA derivativesa (mol/Cmol S) | 0.33 ± 0.02 | 0.27 ± 0.01 | 0.26 ± 0.01 |
| Y ATP/S (ATP/Cmol Sb) | 0.54 ± 0.01 | 0.42 ± 0.01 | 0.41 ± 0.01 |
| Y X/ATP (X/ATP (g/mol ATP) | 7.6 | 12.3 | 8.0 |
The values presented are the average of the samples (three to four) taken in the time period of one week and the respective standard deviation.
aSum of the acetyl-CoA derivatives: acetate, butyrate and ethanol in moles of acetyl-CoA per Cmol of substrate converted
bThe yield of ATP was estimated based on the catabolic products: one ATP per ethanol produced, two ATP per acetate and three ATP per butyrate