The production of cellulosic ethanol has been studied for more than twenty years. However, the full commercialization of this technology is still hindered by process bottlenecks such as the need to operate under low enzyme loadings and high total solids, the yet restricted access to organisms that are able to ferment pentoses and hexoses indistinctively, and the need for optimizing the use of chemicals, utilities and process streams. In the 2012-2013 harvesting season, Brazil produced 597 million tons of sugarcane, which was converted to 39 million tons of sucrose, 23 billion liters of ethanol and approximately 168 million tons of bagasse (wet basis). Although partially utilized for co-generation and bioelectricity, a great deal of these agro-industrial residues is still available for conversion to fuel and chemicals in such a way to improve the economics of the overall process and alleviate the impact of their accumulation in environmentally sensitive areas. In this scenario, pretreatment is a key step for the economic viability of cellulosic ethanol but the selected pretreatment technology must lead to the fractionation of lignocellulosic components at high yields while increasing their accessibility to enzymatic hydrolysis, this without promoting the accumulation of yeast inhibitory compounds as much as possible. In this work, cane bagasse was subjected to steam explosion in the absence and in the presence of catalysis such as dilute phosphoric and sulfuric acids. Also, the role of solvent-extractable organic compounds was assessed in the production of cellulosic ethanol.
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