(719a) Alkaline Based Pretreatments at Great Lakes Bioenergy Research Center

Plant cell wall deconstruction to fermentable sugars in an economically viable and environmentally sustainable manner has been impeded due to native cell wall recalcitrance to thermochemical and biological based processing. Lower severity alkaline based pretreatments can overcome several limitations of traditional approaches (e.g. acidic pretreatments) to producing cellulosic biofuels and biochemicals. Alkaline based pretreatments, using ammonia (e.g. AFEX) and alkaline peroxide as catalysts, are being currently studied and developed at the Great Lakes Bioenergy Research Center (www.glbrc.org) to overcome cell wall recalcitrance. In this presentation, we will review the major developments in our understanding of how alkaline based pretreatments enhance enzymatic digestibility and fermentability of lignocellulosic biomass through various chemical and ultra-structural modifications within the cell wall. An improved understanding of the major rate limiting steps (i.e. cellulose crystallinity, lignin-carbohydrate complexation and biologically inhibitory role of lignin) to efficient cell wall deconstruction have allowed us to develop novel alkaline based pretreatment technologies that will be briefly discussed.