Shock Pretreatment of Biomass for Production of Biofuel from Lignocellulose

Shock pretreatment is a method of treating lignocellulosic biomass to make it more digestible during enzymatic hydrolysis.  It costs only about $3 to 6/tonne biomass, making it easily one of the least expensive pretreatment methods available.  This new pretreatment method involves loading a vessel with a slurry of biomass and water, filling the headspace with a combustible mixture, and igniting it.  The resulting pressure shock disrupts the lignocellulose structure, allowing enzymes to more easily access the cellulose substrate.  When used following lime pretreatment, shock pretreatment allows for a 40% reduction in enzyme loading while maintaining digestibility of glucan and xylose at similar levels to those achieved using only lime pretreatment.  This improves the economy of the process, reducing the estimated cellulose-derived ethanol costs from $4.36 to $4.02 per gallon; this estimate makes combined lime and shock pretreatment competitive with dilute acid pretreatment.  Shock pretreatment helps to bring cellulose-derived biofuels one step closer to commercialization, bringing with it decreased competition for food crops and reduced greenhouse gas emissions when compared to conventional ethanol production.