Starch- and Sugar-Based Ethanol Feedstocks

The vast majority of today's ethanol is derived from starch- and sugar-based feedstocks. The sugars in these feedstocks are relatively easy to extract and ferment using widely available biochemical conversion technologies, making large-scale ethanol production affordable. Starch-based feedstocks include plants such as corn, wheat, and milo. The starches in these plants are chains of sugars that can be broken down into simple sugars before fermentation. Sugar-based feedstocks, such as sugar cane and sugar beets, contain simple sugars that can be extracted and fermented readily. Corn is the feedstock for more than 90% of current U.S. ethanol production. Brazil, the world's second-largest ethanol producer behind the United States, uses sugar cane as a feedstock.

Ethanol production from starch- and sugar-based feedstocks will be limited because of concerns about impacts on land use and food crops. However, these feedstocks are important because they are reducing our petroleum use today while enabling development of an ethanol-based fuel industry, including deployment of feedstock logistical systems, fueling infrastructure, and flexible fuel vehicles. In the long run, cellulosic feedstocks will play the leading role in ethanol production.