Recent progress in converting grain-based feedstock into bioethanol, oils and protein co-products

Authors: Liu, Keshun

Submitted to: Annual Meeting and Expo of the American Oil Chemists' Society
Publication Type: Abstract Only
Publication Acceptance Date: 2/12/2019
Publication Date: 5/5/2019
Citation: Liu, K. 2019. Recent progress in converting grain-based feedstock into bioethanol, oils and protein co-products. Annual Meeting and Expo of the American Oil Chemists' Society. Pro 3.

Interpretive Summary:

Technical Abstract: For the past 15 years, the fuel ethanol industry in United States has grown rapidly. In 2017, 211 U.S. plants converted 139.7 million metric tons (MMT) of grains (mostly corn) into 59.8 billion liters bioethanol, 41.4 MMT protein coproducts, and 1.6 MMT distillers oils, all at record levels. About 90% of ethanol production came from dry-grind processing, by which whole grains are processed through sequential steps of grinding, cooking, liquefaction, scarification, fermentation, distillation, and coproduct recovery. Among many factors driving this steadily increasing bioethanol production, process innovation has been important. Over the years, several modified dry-grind methods have been developed, featured by fractionation before or after fermentation to remove one or more nonfermentable fractions (e.g., oil and/or fiber). Other innovation focused on selecting economically-feasible and locally available feedstocks, channeling co-product streams for alternative treatments/uses, improving starch-hydrolyzing enzymes and fermentation yeast, and fine-tuning processing parameters. All these efforts have improved ethanol production efficiency, reduced cost, changed composition of and added values to co-products. Some new methods have been commercialized. One successful example is production of high-value distillers oils for biodiesel feedstock and high-energy animal feed. China ranks the fourth in ethanol production, after U.S., Brazil, and European Union. In China, wheat and corn are the main feedstocks, but techniques based on energy crops and cellulosic materials are maturing. Because the Chinese government set E10 fuel as a new mandate in 2017, fuel ethanol production is poised to increase, but feedstock selection will always differ from U.S. and other countries.