Bioenergy production from second- and third-generation feedstocks

This chapter aims to provide an update of the state of art of existing feedstocks for biofuel production from lignocellulosic biomasses. Lignocellulosic biomass is considered an important bioresource that can be utilized in many forms. In function of the nature of this lignocellulosic biomass, it is possible to make a difference between three feedstock generations. In the first one, the substrate consists mainly of seeds, potato, and grains, and the production process consists in the purification of simple sugars to obtain ethanol. But, the first-generation biofuels have been perceived as unsustainable from both an environmental and an industrial production cost points of view. So, the research has switched to the development of more advanced biofuels. For this reason, the first-generation feedstocks have been replaced in a first time by a second one (mainly agricultural wastes) and in a second time with a third one (algae). This chapter presents a critical analysis of published data on both the applications and potentiality of the bioenergy production from second and third generation of feedstocks.