Table 2.
The pH and composition of presoaked and raw WWS prehydrolysate
| Sample | Soaking reagent | Concentration (mmol/L) | pH | Carbohydrates (g/L) | Fermentation inhibitors (g/L) | |||||
|---|---|---|---|---|---|---|---|---|---|---|
| Glucose | Xylose | XOS | Formic acid | Acetic acid | Furfural | HMF | ||||
| Raw WWS | No soaking | – | 5.7 ± 0.1 | 0.0 ± 0.0 | 0.7 ± 0.1 | 2.9 ± 0.1 | 0.2 ± 0.0 | 0.7 ± 0.1 | 0.0 ± 0.0 | 0.0 ± 0.0 |
| H2O | – | 5.0 ± 0.3 | 0.0 ± 0.0 | 0.3 ± 0.2 | 3.0 ± 0.1 | 0.2 ± 0.0 | 0.7 ± 0.1 | 0.0 ± 0.0 | 0.0 ± 0.0 | |
| H+ | 30 | 4.9 ± 0.1 | 0.1 ± 0.1 | 0.3 ± 0.3 | 3.3 ± 0.3 | 0.2 ± 0.1 | 0.7 ± 0.0 | 0.1 ± 0.1 | 0.0 ± 0.1 | |
| K+ | 30 | 5.1 ± 0.0 | 0.0 ± 0.0 | 0.2 ± 0.1 | 3.2 ± 0.2 | 0.1 ± 0.0 | 0.7 ± 0.0 | 0.0 ± 0.0 | 0.0 ± 0.0 | |
| Na+ | 30 | 4.8 ± 0.0 | 0.1 ± 0.0 | 0.4 ± 0.0 | 2.9 ± 0.3 | 0.0 ± 0.0 | 0.7 ± 0.1 | 0.0 ± 0.0 | 0.0 ± 0.0 | |
| Ca2+ | 30 | 4.6 ± 0.1 | 0.2 ± 0.0 | 0.5 ± 0.2 | 3.1 ± 0.2 | 0.2 ± 0.1 | 0.8 ± 0.0 | 0.3 ± 0.1 | 0.0 ± 0.0 | |
| Mg2+ | 30 | 4.4 ± 0.0 | 0.2 ± 0.1 | 0.7 ± 0.0 | 3.1 ± 0.1 | 0.3 ± 0.2 | 0.8 ± 0.1 | 0.3 ± 0.2 | 0.0 ± 0.0 | |
| Zn2+ | 30 | 4.1 ± 0.0 | 0.3 ± 0.0 | 1.3 ± 0.0 | 4.0 ± 0.1 | 0.5 ± 0.0 | 1.1 ± 0.0 | 1.1 ± 0.1 | 0.1 ± 0.0 | |
| Fe2+ | 30 | 4.0 ± 0.0 | 0.3 ± 0.2 | 0.9 ± 0.1 | 4.9 ± 0.3 | 0.9 ± 0.0 | 1.5 ± 0.0 | 1.1 ± 0.1 | 0.1 ± 0.0 | |
| Fe2+ | 10 | 4.0 ± 0.0 | 0.1 ± 0.1 | 1.1 ± 0.3 | 4.3 ± 0.4 | 0.8 ± 0.1 | 1.3 ± 0.1 | 1.0 ± 0.0 | 0.1 ± 0.0 | |
| 20 | 4.0 ± 0.2 | 0.1 ± 0.0 | 1.0 ± 0.1 | 4.6 ± 0.1 | 0.9 ± 0.0 | 1.3 ± 0.2 | 1.0 ± 0.1 | 0.2 ± 0.1 | ||
| 30 | 4.0 ± 0.1 | 0.3 ± 0.1 | 0.8 ± 0.0 | 5.1 ± 0.3 | 0.9 ± 0.0 | 1.5 ± 0.0 | 1.2 ± 0.0 | 0.2 ± 0.0 | ||
| 60 | 3.9 ± 0.0 | 0.8 ± 0.2 | 0.7 ± 0.1 | 5.6 ± 0.2 | 0.9 ± 0.1 | 1.6 ± 0.0 | 1.2 ± 0.0 | 0.2 ± 0.0 | ||
| 120 | 3.8 ± 0.1 | 1.0 ± 0.0 | 0.7 ± 0.2 | 6.2 ± 0.2 | 1.1 ± 0.1 | 1.8 ± 0.0 | 1.3 ± 0.1 | 0.3 ± 0.1 | ||