Lignocellulosic biomass conversion into bioenergy-Part 2: Bioethanol production

Part 2: Bioethanol production

To overcome the ecological-energy problem, a series of renewable technologies derived mainly from geothermal, solar thermal, hydro and wind, have been developed. The best solution, which seems to provide a good high-energy output, has been found in converting renewable sources to obtain biofuels. Among the many extractable products derived from renewable raw materials, oils (for biodiesel production through transesterification reactions) and sugars (for ethyl alcohol production by means of fermentation) are very interesting as alternatives to hydrocarbons fuels. If compared with gasoline, Ethanol has higher octane number (99-107 with respect to 82-92), and it can supply up to 66% of the energy provided by the same amount of gasoline; moreover, Ethanol has a higher enthalpy of evaporation in comparison with gasoline (1177 kJ / kg at 60 ° C versus 348 kJ / kg at 60 ° C). Hence bioethanol production could be the route to the effective utilization of agricultural wastes. Rice straw, wheat straw, corn straw, and sugarcane bagasse are the major agricultural wastes in terms of the quantity of biomass available. This second part of the review aims to present a brief overview of the available and accessible technologies for bioethanol production using these major wastes.