No abstract

Increased demand for ethanol as a fuel additive has resulted in dramatic growth in ethanol production. Ethanol is produced from corn by either wet milling or dry-grind processing. In wet milling, the corn kernel is fractionated into different components, resulting in several coproducts. Wet-milling plants are capital intensive because of equipment requirements; they produce large volumes of ethanol and are corporate owned. In dry-grind processing, the corn kernel is not fractionated and only one coproduct, distillers' dried grains with solubles (DDGS), is generated. Dry-grind plants require less equipment and capital than wet mills. They generate smaller volumes of ethanol, are producer owned, and add direct benefits to rural economies. Most of the increase in ethanol production during the past decade is attributed to growth in the dry-grind industry. The marketing of coproducts provides income to offset processing costs. For dry-grind plants, this is especially important, because only one coproduct is available. Several issues could affect DDGS marketing. The increasing volume of DDGS accompanying ethanol production could reduce market value; high phosphorous content could limit the use of DDGS, because of animal waste disposal issues. Water removal is a costly processing step and affects the economics of ethanol processing. Technologies to remove germ and fiber from DDGS could produce a new coproduct suitable for feeding to nonruminants; this would expand the markets for DDGS. Reducing phosphorus in DDGS would sustain markets for conventional DDGS. The development of more efficient methods of water removal would increase the efficiency of ethanol processing and reduce the costs of processing. New technologies could contribute to greater stability of dry-grind plants.

Cereal Chem. 82(2):187-190 Three different modified dry-grind corn processes, quick germ (QG), quick germ and quick fiber (QGQF), and enzymatic milling (E-Mill) were compared with the conventional dry-grind corn process for fermentation characteristics and distillers dried grains with solubles (DDGS) composition. Significant effects were observed on fermentation characteristics and DDGS composition with these modified dry-grind processes. The QG, QGQF, and E-Mill processes increased ethanol concentration by 8-27% relative to the conventional dry-grind process. These process modifications reduced the fiber content of DDGS from 11 to 2% and increased the protein content of DDGS from 28 to 58%.

Iii CoI1\CIItiOI1I dI\-,,i,J coin pIi)cc.. 'atiJi I CiSi\ Cl cd into LIC\[IIIIIS i,stn liquclactioli entymes at high temperatures (90-120'C) during a liquefaction step. Dextrins are hydrolyzed into sugars using saccliaritication enzymes during a simultaneous sacchartfication and fermentation (SSF) step. Recently, a raw starch hydrolyzing enzyme (RSU), Star-en 001, was developed that converts starch into dextrins at low ternperatures (<48°C) and hydrolyzes dextrins into sugars during SSF. In this study, a dry-grind corn process using RSH enzyme was compared with o combinations (DGI and DG2) of commercial liquefaction and s:,ccharification enzymes. Dry-grind corn processes for all enzyme treat-Department of Agricultural and Biological Engineering, University of Illinois.