The sustainable use of bio-based carbon suggests integrated manufacturing in biorefineries to selectively transform the variety of molecular structures available in biomass into a range of products including transportation biofuels, chemicals, polymers, pharmaceuticals, pulp and paper, food, or cattle feed (Cherubini, 2009,, 2010; Kamm et al., 2006a).

The biorefinery concept embraces a wide range of technologies able to separate biomass resources (wood, grasses, corn, etc.) into their building blocks (carbohydrates, proteins, fats, etc.) which can be converted to value-added products, biofuels, and chemicals. A biorefinery is a facility (or network of facilities) that integrates biomass conversion processes and equipment to produce transportation biofuels, power, and chemicals from biomass. Figure 1 gives an overview of the possible conversion pathways to produce the desired energy and material products from different biomass feedstocks, through jointly applied technological processes (Cherubini et al., 2009). The biorefinery concept is analogous to today’s petroleum refinery, which produces multiple fuels and products from petroleum.

Biomass is constituted of an enormous variety of plant species with varying morphology and chemical composition. However, regardless of the phenotype, five main biomass components can be identified worldwide: lipids, starch, cellulose, hemicelluloses, lignin, and proteins. The average biomass available in the world is reported in Figure 2. It clearly appears that lignocellulosic biomass components such as cellulose, hemicelluloses, and lignin are by far the most abundant. Since they can be even gathered from waste streams (e. g., crop residues, paper and wood industries), or directly harvested from forests or biomass stands through sustainable management, their price tend to be lower than other biomass sources which need a dedicated agricultural plot. For this reason, this chapter has a special focus on the possibility to produce commodity chemicals from lignocellulosic sources, which have the largest chances for a massive market penetration in the near future.