Figure 2

Supplementation of commercial cellulases with β-glucosidase LAB25g2. The dosage of β-glucosidases was performed on the basis of same activity towards pNPβG, namely, 31.25 U g^-1 dry biomass (minimum dose of LAB25g2 to achieve saccharification of 20% w/w pre-treated corn stover under assay conditions). Saccharification of lignocellulose is shown by meaning of glucose and cellobiose concentration in assay tests (A) or glucan to glucose conversion (B). Hydrolysis reactions: 100 ml flasks, pH 5.2, 12 g of pre-treated corn stover, 3 g of enzymatic mixture (Celluclast) and 5 g LAB25g2 β-glucosidase solution at 25 U ml^-1 (in the basis of p NPβG assay). Control reactions in the absence of LAB25g2 were performed. Commercial β-glucosidases G0395 (from almond) and E-BGOSAG (from Agrobacterium sp.) were used as control test as for LAB25g2. For that protein solutions at 25 U ml^-1 were prepared and added to reaction mixtures to achieve a final activity of 31.25 U g^-1 dry biomass (p NPβG), as for LAB25g2. Specific activity of those preparations is shown in Additional file 2: Table S2. In both cases, results were similar to those found in the control experiment without β-glucosidase and are not shown. Determination of glucose and cellobiose concentrations was followed by RID-HPLC. Glucose concentration was also measured by the glucose oxidase-peroxidase D-Glucose Assay Kit (Megazyme). All measurements were analysed in triplicate as described in Methods. Error bars are indicated. Note: under similar dosage conditions β-glucosidase Novo-188 (Novozymes A/S) consumed all cellobiose in the assay after 24 h (not shown).