The U.S. biodiesel and ethanol industries are rapidly growing segments of U.S. agriculture. Approximately 40% of fuel ethanol is produced by wet-mills. These plants produce wet or dried corn gluten feed, corn gluten meal and corn germ meal as the primary by-products. 

Dry-grind ethanol plants represent the fastest growing segment of the fuel ethanol industry in the U.S., and produce the majority (60%) of fuel ethanol. By-products from dry-grind ethanol plants include wet and dried distillers grains, wet and dried distillers grains with solubles, modified “wet cake”, and condensed distillers solubles.

The primary by-product of biodiesel production is crude glycerine (glycerol). Glycerine has been used for many years in numerous industrial applications, in pharmaceutical products, in cosmetics and body lotions, and in paper manufacturing. However, with the growing supply of glycerine being produced, new alternative uses are being developed including using crude glycerine as an energy source in livestock and poultry feeds.