Corn ethanol is ethanol produced from corn biomass and is the main source of ethanol fuel in the United States. Corn ethanol is produced by ethanol fermentation and distillation. Corn ethanol results in lower greenhouse gas emissions than gasoline and is fully biodegradable, but environmental concerns ; approximately 40.5% of the U.S. corn croplands are used for ethanol production.
Corn ethanol is mainly added as an oxygenate to gasoline to produce a low-level blend used in motor vehicles. To a lesser extent, it is used as fuel for E85 flex-fuel vehicles.