SSF of different pretreated CS materials. (a) Steam explosion-pretreated CS after 4 days of biodetoxification. (b) Dilute sulfuric acid-pretreated CS after 4 days of biodetoxification. (c) Dilute sulfuric acid-pretreated CS after water-washing detoxification at different liquid-to-solids ratios. Biodetoxification conditions for different pretreated CS: 4 days at 25°C in the static incubator. SSF conditions: 30% (wt/wt) solids loading, 15.0 FPU/g DM, pH 5.0, in the helical stirring bioreactor at 150 rpm. FPU, unit of filter paper cellulase.