Fast-growing and short-rotation biomass is identified as glucan-rich feedstock to be used for bioenergy purposes. For the first time to our knowledge, fast growing biomass (Paulownia tomentosa) was evaluated for bioethanol production in a biorefinery scheme. For that, Paulownia wood was subjected to autohydrolysis pretreatment under severity (S-0) conditions in the range of 3.31-5.16. The effect of this treatment on its fractionation was evaluated by means of hemicelluloses solubilization as heinicellulose-derived compounds in liquid phase and enzymatic hydrolysis of glucan (remained in the solid phase) into glucose. A xylose and xylooligosaccharides concentration of 17.5 was obtained at S-0 = 3.99 which corresponds to complete xylan solubilization. On the other hand, glucose yield of enzymatic hydrolysis increased up to reach 99% at S-0 = 4.82. In addition, separate and simultaneous saccharification and fermentation assays (SHF and SSF) of autohydrolyzed Paulownia were compared for ethanol production. An increase of 47% in ethanol concentration was obtained by SHF in comparison with results achieved by SSF for Paulownia treated at S-0 = 4.19. In SSF, Paulownia was successfully converted into ethanol (52.7 g/L which corresponded to 80% of ethanol yield) operating at 20% solid loadings and S-0 = 4.72. Energy analysis of results obtained in this work showed that 83% of energy respect to raw material can be recovered considering the ethanol and the combustion of residual lignin. This work provides a feasible process for bioethanol production using fast growing specie which could enrich the feedstock needs for biofuels sector. (C) 2016 Elsevier Ltd. All rights reserved.