Production of Bioethanol from Sweet Potato, Agro-Industrial Wastes

One fraction of the existent petroleum is not extractable or the difficulties associated to extraction are very expensive making them unviable. This situation leads to a decrease in petroleum stocks all over the world and a resulting increment on its price, affecting in particular the transportation sector, since there is no relevant alternative to fossil petroleum. In addition, the recent concern about the environmental deterioration from the over consumption of petroleum derived products, which highly contributes to the greenhouse effect, is threatening the sustainability of the human society. For these reasons, the search for clean and renewable sources is one of the highest challenges of mankind nowadays. Biomass is one of the oldest and the most promising energy sources and includes organic and animal wastes, wastewater, energy crops, agricultural and industrial residues that can be used for the production of biofuels. It can be biologically converted to liquid or gaseous fuels, such as ethanol, methanol, methane and hydrogen [1]. Bioethanol is obtained from plant materials that are produced by photosynthesis, which is a photochemical process that uses atmospheric CO2. When the bioethanol is burned, it liberates CO2 that returns back to the atmosphere, where it came from. It means that the balance between CO