Fig. 6

Particle size distributions. Particle size distributions of residual solids from C. thermocellum fermentation of washed senescent switchgrass without (blue) or with brief milling before (red) or after (green) partial fermentation (see Fig. 5). Particle size distribution (mean ± SD, n ≥ 2 except for no milling condition after 1 fermentation stage) is shown for each milling condition either after one (moderate hue) or two (darkest hue) fermentation stages. Measurement of initial partial size distribution was only possible for the milling before condition (lightest color hue). Volume-mean particle size after two fermentations is indicated by the dashed line for each milling condition