Concerning the rapid growth of human population, depletion of natural resources, environmental pollution and climate changes, bioethanol has attracted great attention as octane booster, fuel additive, and even as neat fuel [1], [2] and [3]. Compared with gasoline,bioethanol has many advantages such as higher octane number, broader flammability limits, higher flame speeds, higher heats of vaporization, and less emission of SO2 and CO2[4], [5] and [6]. Also, particulate emission for 10% (E10) and 20% (E20) ethanol blends respectively are decreased by 6.0–6.6% and 29.4–41.8% [7]. Currently, bioethanol are almost produced from grain or sugarcane. USA is the largest scale producer of bioethanol from corn in the world, followed by Brazil from sugarcane. However, these crops cannot meet the global demand for bioethanol production as alternative energy. To diminish the world’s food crisis, lignocellulosic biomass is projected as a virtually eternal raw material for bioethanol production [5].
The technology of bioethanol production from lignocellulosic biomass has been greatly improved [8], [9] and [10]. However, there still exist some challenges which do not support cost-effective and competitive production, thus blocking its commercialization [11], [12] and [13]. These challenges (presented in Fig. 1) mainly include the following aspects: rigorous pretreatment, reduction of cellulase costs, development of more robust industrial strains, approaches for enzymatic hydrolysis and fermentation, and high capital costs associated with complex processes [14] and [15]. Jonker et al. has reported that the costs reduction measures for bioethanol industrial processing include reduction of the feedstock costs, increase of the industrial efficiency and scale, and a change to more advanced industrial process [16].