ABSTRACT
RAJIB BISWAS, HINRICH UELLENDAHL, AND BIRGITTE K. AHRING
9.1 INTRODUCTION
In recent years, ethanol production from renewable sources has received increased attention in a world of dwindling fossil fuels reserves along with the environmental concerns. Commercial production of bioethanol is mostly driven by starch-or sucrose-containing feedstocks such as corn, sugarcane, wheat by fermentation with Saccharomyces cerevisiae (Wheals et al. 1999). Non-food feedstocks, however, such as lignocellulosic materials including agricultural wastes such as bagasse hold significant potential and have been identified as suitable feedstock sources for ethanol production (Lynd et al. 1991). Lignocellulose based ethanol processes require pretreatment as a first step followed by
enzymatic hydrolysis of carbohydrates (Ahring et al. 1996; Margeot et al. 2009). Unlike the hydrolysis of starch-and sugar-based feedstock that results primarily in hexoses, lignocellulose is composed of cellulose and hemicellulose, resulting in both hexoses (C6) and pentoses (C5) sugars (Rubin 2008). An efficient pretreatment strategy along with the fermentation of C6 and C5 sugars are keys to bring cellulosic ethanol to commercial reality.
