Ethanol is considered the next generation transportation fuel with the most potential, and significant quantities of ethanol are currently being produced from corn and sugar cane via a fermentation process. Utilizing lignocellulosic biomass as a feedstock is seen as the next step towards significantly expanding ethanol production capacity. However, technological barriers — including pretreatment, enzyme hydrolysis, saccharification of the cellulose and hemicellulose matrixes, and simultaneous fermentation of hexoses and pentoses — need to be addressed to efficiently convert lignocellulosic biomass into bioethanol. In addition to substantial technical challenges that still need to be overcome before lignocellulose-to — ethanol becomes commercially viable, any ethanol produced by fermentation has the inherent drawback of needing to be distilled from a mixture which contains 82% to 94% water. This section will review current developments towards resolving these technological challenges.