Alcoholic fermentation has been the main focus for these feedstocks with bioethanol as its main product. With the current problems surrounding worldwide food sup­ply, it is not ethically and politically justifiable to use food as a fuel while certain countries suffer famine. However, food conservation and storage may sometimes be very difficult and some considerable amounts of corn and grains may become unfit for human consumption. Nevertheless, considering the high starch content and ap­preciable fermentation yields with this feedstock, it has been rarely studied in fields other than bioconversion.

11.2.1.4 Oilseeds and Plants

Contrary to corn and grains, oilseeds and their plants show very poor starch content. Many species, such as colza, are dedicated to the production of biodiesel. Although biodiesel production has been demonstrated as technically feasible at a large scale, it is not economically sustainable without government grants or incentives. Several studies on oilseeds and plants pyrolysis can be found in the scientific literature, which indicates a strong interest for this conversion technology. As an example, castor bean slow pyrolysis yields easily over 65 % oil with as low as 20 % solid residue [22]. Due to the high oil yield, there is interest in mixing these oils with diesel to produce blends for transportation fuels. However, for the same reasons that were brought in Sect. 11.2.1.5, these feedstocks should not be diverted from their primary function, namely food supply.