Table 1 Enzymes expressed and characterized in T. reesei for the degradation of hemicellulose and cellulose, grouped according to their functionality.
Group | Functionality | Enzymes in T. reesei | EC |
|---|---|---|---|
Enzymes for the degradation of hemicellulose | |||
 Backbone cleaving enzymes | Degradation of the xylan backbone in arabinoxylan (hardwood) and arabinoglucoronoxylan (grasses) by endo- and exo-xylanases | Endo-β-1,4-xylanase | 3.2.1.8 |
1,4-β-Xylosidase | 3.2.1.37 | ||
Xyloglucan-specific endo-β-1,4-glucanase | 3.2.1.151 | ||
Degradation of the mannan backbone in galactoglucomannan (softwood) by endo- and exo-mannanases | Endo-1,4-β-mannosidase | 3.2.1.78 | |
β-Mannosidase | 3.2.1.25 | ||
1,2-α-Mannosidase | 3.2.1.113 | ||
β-Galactosidase | 3.2.1.23 | ||
 Side-chain cleaving hydrolytic enzymes | Cleaving off galactose moieties from galactoglucomannan (softwood) | α-Galactosidase | 3.2.1.22 |
Cleaving off arabinose moieties from arabinoxylan (hardwood) and arabinoglucoronoxylan (grasses) | α-l-Arabinofuranosidase | 3.2.1.55 | |
Cleaving off glucoronic moieties from arabinoxylan (hardwood) and arabinoglucoronoxylan (grasses) | α-Glucuronidase | 3.2.1.139 | |
 Side chain cleaving esterases | Cleaving off acetyl groups from glucuronoxylan (hardwood), arabinoglucoronoxylan (grasses), and galactoglucomannan (softwood) | Acetyl xylan esterase | 3.1.1.72 |
Cleaving ester linkage between arabinose in hemicellulose and ferulic acid in lignin | Acetyl esterase | 3.1.1.6 | |
Enzymes for degradation of cellulose | |||
 Concerted action of exo- and endo-cellulases and β-glucosidase | Endo-β-1,4-glucanase | 3.2.1.4 | |
1,4-β-Cellobiosidase | 3.2.1.91 | ||
β-Glucosidase | 3.2.1.21 | ||
 Auxiliary activities | Cleavage of cellulose chains by oxidation of C1 or C4 | Lytic polysaccharide monooxygenases | 1.14.99.56 |
 Non-hydrolytic proteins | High binding affinity for hemicellulose and cellulose, unknown role in biomass degradation | Swollenin | – |