Ethanol From Biomass: Future and Perspectives

Nowadays, the world’s energy requirements are based on the use of fossil fuels. Rapid growth in both global energy demand and carbon dioxide emissions associated with the use of these fuels have driven the research for alternative sources, which are renewable and have a lower environmental impact. Ethanol is considered one of them. In fact, it is considered one of the better biofuels for transport: it can be burned directly or blended with petrol to improve fuel combustion in vehicles, resulting in lower CO2 emission to reduce greenhouse gases in the atmosphere. The optimization of the ethanol production processes from lignocellulosic biomass is considered an important research from both industrial and research point of view. In function of the nature of the raw material, it is possible to distinguish these three different feedstock generations. In the first generation, the substrate consists mainly of seeds, potato, and grains and the production process consists of the purification of simple sugars to obtain ethanol. Nevertheless, the first generation of biofuels has been perceived as sustainable mainly from both an environmental and limitation in food supply point of view. This has meant that research has switched to the development of more advanced technology to obtain an energy sustainability to minimize greenhouse gases emission. For these reasons, other two different production processes have been developed, focusing on the fermentation of cellulose and hemicellulose from mainly agricultural wastes (second generation) and algae (third generation). This chapter represents a critical analysis of published data on application and potentiality of the bioethanol production from first, second and third generation of feedstock.