Fig. 6

SEM images obtained at low magnification (100 ×) using the secondary electron signal from Norway spruce wood subjected to different pretreatments and subsequent enzymatic hydrolysis. A STEX180°C/auto, B STEX210°C/auto, C STEX210°C/HAc, D STEX210°C/H3PO4, E STEX210°C/H2SO4, and F STEX210°C/SO2