Fungal Pretreatment of Corn Stover Fractions for Ethanol Production

Ethanol produced from biomass, such as corn grain or sugar cane, is a renewable fuel that helps lessen dependence on petroleum-based fossil fuels. Currently, the majority of ethanol production in the United States utilizes corn grain, which supplied about 14 billion gallons of ethanol to the market in 2012. In the near future, corn supplies for ethanol are expected to be limited due to concerns that corn grown for fuel limits or competes with corn grown for feed and food. However, lignocellulosic biomass is abundant in the United States, and has the potential to produce fuel ethanol to meet 30% of current gasoline consumption; nevertheless, this technology faces significant challenges. Corn stover is the biomass remaining after harvesting the grain and is the most abundant agricultural residue in the United States, with an estimated 170–256 million tons available annually. Unlike corn grain, the carbohydrates in lignocellulosic biomass are not readily available for ethanol production, so pretreatment is required. Pretreatment processes that use harsh chemicals or steam can be effective, but currently are not economically feasible and/or environmentally sustainable. This fact sheet discusses research on the effectiveness of using a white-rot fungus to pretreat three different corn stover fractions: leaves, stalks and cobs.