*Mass of ethanol formed per mass of glucose consumed.
Several techniques including direct fermentation, simultaneous saccharification, simultaneous non-thermal saccharification, ultrasound assisted treatment and solid-state fermentation have been studied previously using different starchy materials and microbial sources for the production of bioethanol [20, 21, 51–56]. Along with this ethanol has also been produced by repeated batch culture through immobilization of S. cerevisiae and S. pastorianus IFO0751 on calcium alginate and porous cellulose carriers, respectively [57, 58]. Nikolic et al. [54] used ultrasound-assisted treatment for direct conversion of corn meal into bioethanol but the cost related to this method in amount of energy consumption is very high. Beside this, the pretreatment of multiple biomass or starch flour will also add extra budget that will eventually affect the feasibility of the bioethanol. The attempt made in the current study by consuming commercially available cheap cassava starch along with saccharification by synergistic effect of fungal amylolytic enzymes had revealed that this two-step based method can be used to achieve higher yields of bioethanol. Further, the process cost can also be reduced by using other inexpensive starchy materials or by establishing pilot programs that will scrutinize the actual feasibility and sustainability of the overall process developed.