Table 3.
Dissolution and degradation of P. trichocarpa wood at various dilute acid pretreatment regimes
| Regime | Time (min) | H2SO4 | Dissolved sugars | Wood residue | Degraded | Xyl O:M | Glc O:M | Acetate | |||
|---|---|---|---|---|---|---|---|---|---|---|---|
| AA | XOS | WR | AA:XOS:WR | ||||||||
| 1 | 10 | 0.0 | 33 | 930 | ND | 0.6 | 1.1 | 0.6 | ND | 50 | 1.0:ND:83 |
| 2 | 10 | 1.0 | 34 | 910 | ND | 1.8 | 1.1 | 1.4 | ND | 48 | 1.0:ND:34 |
| 3 | 10 | 3.0 | 33 | 880 | ND | 7.1 | 1.0 | 1.4 | ND | 50 | 1.0:ND:36 |
| 4 | 10 | 6.0 | 33 | 880 | ND | 3.2 | 1.2 | 1.6 | ND | 50 | 1.0:ND:31 |
| 5 | 30 | 0.0 | 38 | 880 | ND | 100 | 2.2 | 0.6 | ND | 50 | 1.0:ND:83 |
| 6 | 30 | 1.0 | 140 | 840 | ND | 4.5 | 2.1 | 3.0 | 12 | 41 | 1.0:4.0:13.7 |
| 7 | 30 | 3.0 | 280 | 740 | ND | 1.1 | 1.1 | 18 | 15 | 24 | 1.2:1.0:1.6 |
| 8 | 30 | 6.0 | 380 | 720 | ND | 0.5 | 0.5 | 37 | ND | 5.4 | 6.9:ND:1.0 |
| 9 | 60 | 0.0 | 280 | 720 | ND | 20 | 4.8 | 4.1 | 21 | 50 | 1.0:5.1:12.2 |
| 10 | 60 | 1.0 | 370 | 700 | ND | 0.4 | 0.3 | 40 | 5.5 | 3.0 | 13.3:1.8:1.0 |
| 11 | 60 | 3.0 | 340 | 690 | 74 | 0.2 | 0.2 | 54 | ND | ND | 1.0:ND:ND |
| 12 | 60 | 6.0 | 210 | 680 | 230 | 0.8 | 0.3 | 58 | ND | ND | 1.0:ND:ND |
Pretreatment temperature was 180 °C. H 2 SO 4 sulphuric acid, Glu glucose, Xyl xylose, O:M oligomer-to-monomer ratio; Acetate partitions into acetic acid (AA), dissolved acetate on xylooligosaccharides (XOS), and acetate on wood residue (WR). ND not detected (less than 5% w/w). Values are the average of three technical replicates. Soluble lignin and minor sugars arabinose, rhamnose and galactose are not included in the mass balance. All values except ratios are mg/g