Glycoside hydrolases and Accessory Proteins from Wood Decay Fungi Enhances Sugarcane Bagasse Saccharification

Glycoside hydrolases (GHs) and accessory proteins are key components for hydrolysis in modern biorefineries. Currently, commercialized GHs and accessory proteins are produced by ascomycetes. A team led by Fernanda Valadares from Universidade de São Paulo in Brazil now studies the proteins from wood decay fungi for their use in improving enzymatic cocktails.

GHs and accessory proteins were produced by brown-rot fungi Laetiporus sulphureus and white-rot fungi Pleurotus ostreatus. Protein extracts were then used to modify commercial cocktails for saccharification of pretreated sugarcane bagasse. The main enzymatic activities found in the wood decay fungal protein extracts were attributed to endoglucanases, xylanases and β-glucosidases.

Conversion rates were boosted when the wood decay fungal proteins were used to modify the commercial cocktails. Proteomic studies revealed 104 and 45 different proteins in the P. ostreatus and L. sulphureus extracts, respectively. The enhancement of the saccharification of pretreated substrates by the modified cocktails was attributed to GH5- and GH45-endoglucanase, GH3-β-glucosidase, and GH10-xylanase protein families.

The proteins produced by wood decay fungi provide useful tools to improve commercial enzyme cocktails currently used for the saccharification of pretreated lignocellulosic feedstock.