Sugarcane bagasse saccharification by purified β-glucosidases from Chrysoporthe cubensis

Abstract

A set of β-glucosidases from the phytopathogenic fungus Chrysoporthe cubensis was partially purified, characterized and evaluated for its potential application in the process of sugarcane bagasse saccharification. C. cubensis was grown in solid state fermentation (SSF) containing wheat bran as carbon source. The group of β-glucosidases, containing at least three β-glucosidases, was purified through ion exchange and gel filtration chromatography. The set of β-glucosidases exhibited maximum activity at pH 4.0 and 60 °C and showed high thermal stability at 50, 60 and 70 °C. The β-glucosidases were specific for hydrolysis of glucose residues in the β position. The km values of 0.132 and 0.7816 mM were obtained using ρNPβGlc and cellobiose as substrates, respectively. The β-glucosidases were competitively inhibited by glucose, with Ki value of 8.43 mM. Saccharification of pretreated sugarcane bagasse by a commercial enzyme cocktail supplemented with the β-glucosidases promoted efficient release of sugars. Saccharification performed by the Chrysoporthe cubensis extract supplemented with β-glucosidases promoted a higher xylose yield. The results suggest that β-glucosidases from Chrysoporthe cubensis have great potential to be used as a supplement of enzymatic preparations.