17982: Evaluation of the biotechnological potential of sugarcane straw for second generation ethanol production

The sugarcane straw is still burning before the harvest of the sugarcane and that cause serious environmental problems, especially by the CO_x emission and atmospheric pollution with ash in the local areas. Additionally, this practice is responsible for the soils nutrient loss and erosion increases. The sugarcane straw became a major agricultural waste since the law 11.241 (19/September/2002) that obligates to the gradual harvest mechanization without burn it. This lignocellulosic material represents a great potential to be used as feedstock for second generation ethanol production inner biorefinery concept. In this work, the sugarcane straw potential for ethanol production was evaluated using cellulosic and hemicellulosic fractions. The lignocellulosic material was composed by 22,46% cellulose, 20,17% hemicellulose and 18,2% lignin. For hemicellulosic uptake, diluted acid pretreatment conditions were optimized by experimental design to obtain high xylose content liquor (47 g/L). A final ethanol concentration of 20 g/L was achieved in xylose bath fermentation by Pichia stipitis yeast. Alkali deslignification of the acid pretreated solid was the best method to increase the solid digestibility for Simultaneous Saccharification and Fermentation (SSF). The synergism of Saccharomyces cerevisiae and commercial cellulase (Multifect CX 10 L- Genencor S.A) during SSF process resulted in more than 50 g/L final ethanol concentration when the best solid:liquid ratio was used (1:5 g:mL).