Fig. 4

Fractional total carbohydrate solubilization (a) and gas production (b) for Populus trichocarpa fermentation by C. thermocellum with and without augmentation. Augmentation categories are cotreatment, and cosolvent-enhanced lignocellulosic fractionation (CELF) and none. Natural variant GW9947 P. trichocarpa contains a mutation in the lignin pathway resulting in lower lignin content and BESC97 is a control P. trichocarpa line. Solubilization results (a) are based on equal glucan loadings after 120 h of incubation from duplicate fermentation runs. Error bars for solubilization results represent one standard deviation and are based on biological replicates. For each solubilization bar, one representative gas production data set is shown (b); the gas production data are a percentage of each respective maximum gas production value after 120 h. An asterisk (*) indicates that the difference in solubilization between cotreatment and CELF was statistically significant at p ≤ 0.05. Details of the statistical analysis are presented in Additional file 2: Table S4