Napier grass is a potential feedstock for biofuel production because of its strong adaptability and wide availability. Compositional analysis has been done on Napier grass which was collected from a local area of Taiwan. By comparing acid-and alkali-pretreatment, it was found that the alkali-pretreatment process is favorable for Napier grass. An overall glucose yield of 0.82 g/g-glucose(total) can be obtained with the combination of alkali-pretreatment (2.5 wt% NaOH, 8 wt% sample loading, 121 degrees C, and a reaction time of 40 min) and enzymatic hydrolysis (40 FPU/g-substrate). Semi-simultaneous saccharification fermentation (sSSF) was carried out, where enzymatic hydrolysis and ABE fermentation were operated in the same batch. It was found that after 24-h hydrolysis, followed by 96-h fermentation, the butanol and acetone concentrations reached 9.45 and 4.85 g/L, respectively. The butanol yield reached 0.22 g/g-sugar(glucose+xylose). Finally, the efficiency of butanol production from Napier grass was calculated at 31%. (C) 2017 Elsevier Ltd. All rights reserved.