The ground sorghum bagasse is rehydrated with steam at atmospheric pressure and impregnated with low amounts (up to 3% w/w) of sulfur dioxide (SO2) in plastic bags for 20-30 minutes in order to improve enzymatic saccharification (Sipos et al., 2009; Stenberg et al., 1998; Ohgren et al., 2005). The impregnated bagasse is introduced into a reactor and the temperature is maintained by injection of saturated steam, varying in a range of 170-210°C (Sipos et al., 2009; Stenberg et al., 1998; Ohgren et al., 2005). After 2 to 10 minutes, the blow­down valve is opened and the hydrolyzate is released into a cyclone (Stenberg et al., 1998). Sipos et al. (2009) achieved an extraction of 89% to 92% of cellulose with steam explosion, up to 18 g glucose, 23 g xylose and 5.5 g arabinose/L hydrolyzate. Ballesteros et al. (2003) used steam explosion pretreatment without sulfur dioxide and obtained around 50% of solids recovery and only 20% solubilization of the cellulose. Hemicellulose sugars were extensively solubilized because the raw material had originally 25% xylose and after the treatment only 2% remained on the fibrous residue.