Introduction
Materials and methods
Enzymes and pulp
High and low consistency pulp treatments
Analysis of solubilized sugars
Analysis of fibre morphology
Fibre characterisation
Analysis of fibre porosity
Analysis of OH accessibility with deuterium exchange
Analysis of fibre dissolution in CED
Results and discussion
Short name | Enzyme | CBM domaina | Size (kDa) | Dimensions (PDB code of model structure)d | pH optimum | Temperature optimum |
---|---|---|---|---|---|---|
GH45 + CBM | Melanocarpus albomyces Cel45A | CBM1 | 37 kDab | n.a. | n.a. | n.a. |
GH45 core | Melanocarpus albomyces Cel45A | – | 20 kDaa | 3 × 5 nm (1LF8) | 5–7e | 60–70 °Ce |
GH7 + CBM | Trichoderma reesei Cel7B | CBM1 | 51.9 kDac | n.a. | 5f | 55 °Cg |
GH7 core | Trichoderma reesei Cel7B | – | 42.9 kDac | 4 × 7 nm (1EG1) | n.a. | n.a. |
GH5 + CBM | Trichoderma reesei Cel5A | CBM1 | 48.2 kDac | n.a. | 4.8h | 60 °Ci |
GH5 core | Trichoderma reesei Cel5A | – | 42.2 kDac | 4 × 6 nm (3QR3) | n.a. | n.a. |
Carbohydrate yield loss
Microscopy imaging of fibres
Enzyme used (dry matter content) | Mn (kDa) | Mw (kDa) | Polydispersity (Mw/Mn) | Fibre length (mm)a | Fibre width (µm)b | Fines (%)c |
---|---|---|---|---|---|---|
Ref. no enzyme (20%) | 84 ± 0.4 | 890 ± 26 | 10.7 | 1.76 ± 0.01 | 29.2 ± 0.3 | 8.4 |
GH45 + CBM (20%) | 51 ± 2 | 450 ± 10 | 8.8 | 0.89 ± 0.01 | 30.7 ± 0.2 | 41.2 |
GH45 core (20%) | 51 ± 0.2 | 440 ± 1 | 8.6 | 0.75 ± 0.01 | 30.8 ± 0.2 | 40.0 |
GH7 + CBM (20%) | 57 ± 2 | 660 ± 16 | 11.5 | 1.75 ± 0.01 | 29.8 ± 0.2 | 8.1 |
GH7 core (20%) | 60 ± 5 | 620 ± 34 | 10.3 | n.d. | n.d. | n.d. |
GH5 + CBM (20%) | 65 ± 8 | 630 ± 10 | 9.7 | n.d. | n.d. | n.d. |
GH5 core (20%) | 68 ± 2 | 640 ± 3 | 9.5 | n.d. | n.d. | n.d. |
Porosity measurements
Fibre treatment (dry matter content) | Total pore volume (FSP) (ml/g) | Micropore volume (ml/g) |
---|---|---|
Ref. (1%) | 0.83 ± 0.06 | 0.52 ± 0.01 |
Ref. (20%) | 0.91 ± 0.01 | 0.56 ± 0.01 |
GH45 + CBM (1%) | 0.89 ± 0.01 | 0.52 ± 0.00 |
GH45 + CBM (20%) | 0.95 ± 0.07 | 0.68 ± 0.03 |
GH45 core (20%) | 1.11 ± 0.03 | 0.70 ± 0.01 |
GH7 + CBM (20%) | 0.94 ± 0.03 | 0.53 ± 0.00 |
GH7 core (20%) | 1.02 ± 0.01 | 0.55 ± 0.01 |
GH5 + CBM (20%) | 1.02 ± 0.01 | 0.56 ± 0.00 |
GH5 core (20%) | 0.87 ± 0.03 | 0.43 ± 0.01 |