title: Composition of corn dry-grind ethanol by-products: DDGS, wet cake, and thin stillage.
abstract: DDGS and wet distillers' grains are the major co-products of the dry grind ethanol facilities. As they are mainly used as animal feed, a typical compositional analysis of the DDGS and wet distillers' grains mainly focuses on defining the feedstock's nutritional characteristics. With an increasing demand for fuel ethanol, the DDGS and wet distillers' grains are viewed as a potential bridge feedstock for ethanol production from other cellulosic biomass. The introduction of DDGS or wet distillers' grains as an additional feed to the existing dry grind plants for increased ethanol yield requires a different approach to the compositional analysis of the material. Rather than focusing on its nutritional value, this new approach aims at determining more detailed chemical composition, especially on polymeric sugars such as cellulose, starch and xylan, which release fermentable sugars upon enzymatic hydrolysis. In this paper we present a detailed and complete compositional analysis procedure suggested for DDGS and wet distillers' grains, as well as the resulting compositions completed by three different research groups. Polymeric sugars, crude protein, crude oil and ash contents of DDGS and wet distillers' grains were accurately and reproducibly determined by the compositional analysis procedure described in this paper.
authors.affiliation: Laboratory of Renewable Resources Engineering, Potter Engineering Center, 500 Central Drive, Department of Agricultural and Biological Engineering, Purdue University, West Lafayette, IN 47907-2022, USA.
authors.forename: Youngmi
authors.initials: Y
authors.lastname: Kim
authors.forename: Nathan S
authors.initials: NS
authors.lastname: Mosier
authors.forename: Rick
authors.initials: R
authors.lastname: Hendrickson
authors.forename: Thaddeus
authors.initials: T
authors.lastname: Ezeji
authors.forename: Hans
authors.initials: H
authors.lastname: Blaschek
authors.forename: Bruce
authors.initials: B
authors.lastname: Dien
authors.forename: Michael
authors.initials: M
authors.lastname: Cotta
authors.forename: Bruce
authors.initials: B
authors.lastname: Dale
authors.forename: Michael R
authors.initials: MR
authors.lastname: Ladisch
mesh_terms: D018533:Biomass; D002482:Cellulose / Q000378:metabolism; D000431:Ethanol / Q000737:chemistry* / Q000378:metabolism*; D007220:Industrial Waste; D012820:Silage; D012995:Solubility; D003313:Zea mays / Q000378:metabolism*
chemical_list: D007220:Industrial Waste; D000431:Ethanol; D002482:Cellulose