Distillers Dried Grains with Solubles (DDGS) Currently corn grain is the primary biological material that can be economically converted into ethanol on an industrial scale. The corn-based fuel ethanol industry is poised to produce substantial quantities of biofuel during the coming century as this industry continues its rapid expansion. The number of corn ethanol plants, and their processing capacities, has been markedly increasing in recent years. For example, at the end of 2005, 97 manufacturing plants in the U.S. had an aggregate production capacity of nearly 16.3 billion L/y (4.3 billion gal/y), which represents a growth of 226% over the previous five year period. More information on the growth of this industry can be found in Lyons (2003), BBI (2006), and RFA (2006).