Department of Food Science and Human Nutrition, Center for Crops Utilization Research, Iowa State University, Ames, IA 50011, USA.
Bioresour Technol. 2012 Sep;120:140-8. doi: 10.1016/j.biortech.2012.04.071. Epub 2012 May 8.
Soy skim, a protein-rich liquid co-product from the aqueous extraction of soybeans, was co-fermented with corn to produce ethanol. Effects of soy skim addition level, type of skim, corn particle size, water-to-solids ratio, and urea on co-fermentation were determined. The addition of 20-100% skim increased the fermentation rate by 18-27% and shortened the fermentation time by 5-7h without affecting ethanol yield. Finely ground corn or high water-to-solids ratio (≥ 3.0) in the mash gave higher fermentation rates, but did not increase the ethanol yield. When the water was completely replaced with soy skim, the addition of urea became unnecessary. Soy skim retentate that was concentrated by nanofiltration increased fermentation rate by 25%. The highest level of skim addition resulted in a finished beer with 16% solids, 47% protein (dwb) containing 3.6% lysine, and an ethanol yield of 39 g/100g dry corn.
脱脂豆粕是大豆水提取的富含蛋白质的液体副产物，可与玉米共发酵生产乙醇。本文研究了脱脂豆粕添加量、脱脂豆粕种类、玉米粒度、水料比和尿素对共发酵的影响。添加 20-100%的脱脂豆粕可使发酵速率提高 18-27%，发酵时间缩短 5-7h，而不影响乙醇产量。在醪液中使用细磨玉米或高水料比（≥3.0）可提高发酵速率，但不会增加乙醇产量。当水完全被脱脂豆粕取代时，添加尿素变得不必要。通过纳滤浓缩的脱脂豆粕截留液可使发酵速率提高 25%。最大的脱脂豆粕添加量可使成品啤酒的固形物含量达到 16%，干物质基础的蛋白质含量为 47%（dwb），其中赖氨酸含量为 3.6%，乙醇得率为 39g/100g 干玉米。
