TABLE 3.
The production of by-products and percentage of ATP loss due to by-product production by Z. mobilis ZM4(pZB5) in xylose, glucose, or mixed glucose-xylose media
| Fermentation product | Xylose concn (g/liter)
|
Glucose concn (g/liter)
|
Glucose concn-xylose concn (g/liter)
|
||||
|---|---|---|---|---|---|---|---|
| 27.8 | 40.3 | 60.5 | 27.5 | 64.8 | 26.8/32.0 | 60.0/61.5 | |
| Ethanol | 12.6 | 17.0 | 25.1 | 13.3 | 30.5 | 27.0 | 55.7 |
| Xylitol | 1.37 | 2.68 | 4.86 | 0 | 0 | 0.45 | 0.91 |
| Dihydroxyacetone | 0.68 | 1.34 | 2.10 | 0 | 0.14 | 0.25 | 0.88 |
| Glycerol | 0.36 | 0.80 | 1.26 | 0 | 0.10 | 0.14 | 0.45 |
| Acetic acid | 0.47 | 0.67 | 1.21 | 0.08 | 0.17 | 0.23 | 0.68 |
| Acetoin | 0.12 | 0.15 | 0.18 | 0.22 | 0.32 | 0.25 | 0.52 |
| Lactic acid | 0.017 | 0.016 | 0.022 | 0.008 | 0.014 | 0.022 | 0.035 |
| Theoretical maximum ATP produced from sugar(s) utilized (mmol)a | 185.2 | 268.5 | 403.1 | 152.6 | 359.6 | 361.9 | 742.7 |
| Loss of ATP for by-product production (mmol)b | 32.0 | 64.8 | 106.4 | 0 | 5.3 | 11.6 | 35.3 |
| % ATP loss | 17.3 | 24.1 | 26.4 | 0 | 1.5 | 3.2 | 4.8 |
a
The sugar concentrations were converted to micromoles per liter by dividing xylose concentration (gram/liter) by 0.150 and glucose concentration (gram/liter) by 0.180.
b
The amount of ATP lost due to by-product production was calculated from the concentrations of dihydroxyacetone, glycerol, and xylitol produced during fermentation.