Critical review on ethanol producing feedstock and methods

Dwindling of fossil fuels and the change in global climate have led humankind to explore alternative energy resources. In the force to explore inexhaustible and sustainable resources, research in the domain of solar, wind, tidal, biomass and geothermal are delved into. The energy derived from these various domains proved to be the solution to the greater cause of climate change. Among all these various sources of energy, biomass have tremendous potential. Bioethanol produced from biomass is an attractive biofuel having great prospect for energy security and environmental safety over fossil fuels. The conversion process of biomass to ethanol have improved significantly over the years to make it a viable option in transportation sector thereby reducing dependency on petrol and diesel. The major steps in typical conversion process include pre-treatment, enzymatic hydrolysis, and fermentation of sugars, greatly influenced by microbial strains. Yeast saccharomyces cerevisiae and a bacterial species, zymomonas mobilis, are the two most widely used in ethanol fermentation technology. The final yield of ethanol is directly dependent on the various factors affecting the production process. This comprehensive review study gives an overview of second-generation bioethanol production in regard with the various factors affecting its overall production process.