Conversion of Distiller's Grain into Fuel Alcohol and a Higher-Value Animal Feed by Dilute-Acid Pretreatment

Research output: Contribution to conferencePaper


Over the past three decades ethanol production in the United States has increased more than 10-fold, to approx 2.9 billion gal/yr (mid-2003), with ethanol production expected to reach 5 billion gal/yr by 2005. The simultaneous coproduction of 7 million t/yr of distiller's grain (DG) may potentially drive down the price of DG as a cattle feed supplement. The sale of residual DG for animal feed isan important part of corn dry-grind ethanol production economics; therefore, dry-grind ethanol producers are seeking ways to improve the quality of DG to increase market penetration and help stabilize prices. One possible improvement is to increase the protein content of DG by converting the residual starch and fiber into ethanol. We have developed methods for steam explosion, SO2, and dilutesulfuric acid pretreatment of DG for evaluation as a feedstock for ethanol production. The highest soluble sugar yields (~77% of available carbohydrate) were obtained by pretreatment of DG at 140..deg..C for 20 min with 3.27 wt% H2SO4. Fermentation protocols for pretreated DG were developed at the bench scale and scaled to a working volume of 809 L for production of hydrolyzed distiller's grain(HDG) for feeding trials. The pretreated DG was fermented with Saccharomyces cerevisiae D5A, with ethanol yields of 73% of theoretical from available glucans.
Original languageAmerican English
Number of pages21
StatePublished - 2004
EventTwenty-Fifth Symposium on Biotechnology for Fuels and Chemicals - Breckenridge, Colorado
Duration: 4 May 20037 May 2003


ConferenceTwenty-Fifth Symposium on Biotechnology for Fuels and Chemicals
CityBreckenridge, Colorado

Bibliographical note

Posted with permission from Humana Press.

NREL Publication Number

  • NREL/CP-510-34013


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