Figure 4
Saccharification of pretreated bagasse by mixtures of Cellic CTec2 and transgenic corn stover leaf extracts. (a) H2SO4 steam explosion. (b) NaOH steam explosion. (c) Glycerol/HCl steam explosion. (d) EC/EG. (e) BMIMCl. (f) Ball-milling. Cellic CTec2 at a dosage of 2 FPU/g glucan was supplemented with MULase activity from transgenic corn stover leaf extract (black symbols) and used to saccharify pretreated bagasse for 24 h. Each unit on the x-axis represents the total MULase activity present in Cellic CTec2. Values above 1 indicate the addition of MULase activity from transgenic corn stover leaf extract (black symbols) to Cellic CTec2. Each additional unit of MULase activity supplied from transgenic corn stover leaf extract containing CBH is equal to the total MULase activity in Cellic CTec2 at a dosage of 2 FPU/g glucan. Each reaction was supplemented with 50 μg β-glucosidase/g glucan. Equal volumes of extracts from non-transgenic corn stover leaves prepared under the same conditions were assessed for comparison (open symbols). Glucose release from cellulose was monitored using a colorimetric (GOPOD) assay and the results reported as the percentage of glucan converted to glucose. All samples were analysed in triplicate, and error bars represent standard deviation.