ABSTRACT
Bioethanol is among one of the most promising biofuels that can be a suitable alternative to gasoline. It can be produced using agricultural feedstocks (mostly comprising of sugar and starch) through microbial fermentation process. Conventionally, most bioethanol was produced using corn or sugarcane; however, the running debate over food vs. fuel has necessitated the search for alternate feedstocks. Ethanol is frequently blended with gasoline in the range of 10–85 percent (v/v) to reduce the greenhouse gas emissions. Moreover, it can be used as fuel in direct ethanol fuel cells to generate electricity. At present, bioethanol production has various challenges and limitations such as handling and transport of the feedstock, inefficient biomass pre-treatment methods, and lower energy efficiency. The current estimated costs of bioethanol are not that attractive and most of the expenses are incurred from the feedstock costs. Furthermore, ethanol tends to absorb water from the air which leads to high corrosion aggressiveness in combustion engines. In this chapter, the current status of ethanol production from various feedstocks and the conversion technologies involved are highlighted. In addition, the economics and the environmental impact of the bioethanol production technologies have been discussed in detail.
