Figure 7
Prussian blue staining of dilute acid/ferrous ion cocatalyst-pretreated corn stover. (A) and (B) Bright-field images of Prussian blue staining of dilute acid/ferrous ion-pretreated corn stover (CS) using short and long exposure times with a microscope fitted with a camera, respectively. (C) Autofluorescence images of lignin in the same area shown above. (D) The overlay of Prussian blue staining and lignin autofluorescence images. For sample preparations, the milled CS was pretreated with 0.5 wt% sulfuric acid and 5 mM ferrous sulfate and pretreated at 150°C for 20 minutes. An approximately 100-mg aliquot was taken from well-mixed, pretreated samples and transferred to Prussian blue staining buffer using the regular Prussian blue staining and imaging procedures described in the Methods section.