Restructuring the processes for furfural and xylose production from sugarcane bagasse in a biorefinery concept for ethanol production

This study consisted in restructuring the processes for furfural and xylose production from sugarcane bagasse in a biorefinery concept for the residues utilization on ethanol production. The dilute acid hydrolysis conditions for furfural or xylose production were firstly established on laboratory scale and then reproduced on a 10-L bench reactor fed with direct steam. The furfural production was maximum when using a 1.25% (w/w on dry fiber) H2SO4 solution at 175 °C during 40 min; whereas the xylose production attained the best results when using a 1% (w/v) H2SO4 solution in a solid/liquid ratio of 1/4 (g/mL), and the sugarcane bagasse impregnated with the acid solution during 24 h prior to the hydrolysis reaction. Enzymatic hydrolysis of the residual solid material obtained from furfural or xylose production was performed with yields of 17.4 and 9.3 g glucose/100 g initial raw material, respectively. Subsequently, ethanol was produced from the residual solid materials obtained from furfural and xylose production with yields of 87.4% and 89.3% respectively, based on the maximum theoretical value (0.51 g ethanol per g glucose in hydrolysate). Such results demonstrated the possibility of restructuring the processes for furfural or xylose production to obtain solid residues able to be used as substrate for ethanol production by fermentation.