Before enzymes can efficiently hydrolyse the sugar components of biomass, biomass needs to be pre-treated to expose these sugars to enzymatic attack. Why is this necessary? Well the highly complex lignocellulosic matrix consisting of Cellulose, hemicellulose and lignin forms a barrier against enzymes which prevents degradation of the biomass into its individual components.
Steam explosion is one man-made way in overcoming this barrier, or in other words overcome the recalcitrant propery of biomass that is observed in nature. By subjecting biomass to high pressure steam for a certain period of time and then explosively depressurizing the biomass through release of steam/biomass one can break apart the lignocellulosic structure effectively yielding a highly digestible substrate.
Compare the following pictures of raw un-pretreated triticale straw with that that has been steam exploded at a steam temperature of around 200 degrees and a residence time of 5 – 10 minutes. One can visually see how the biomass has been fragmented and destroyed by this pretreatment technology.
Raw unpretreated triticale straw
Steam Exploded triticale straw
Lignofuel 