Submitted to: Cereal Chemistry
Publication Type: Peer reviewed journal
Publication Acceptance Date: 3/1/2007
Publication Date: 3/1/2007
Citation: Wu, X., Zhao, R., Bean, S., Seib, P.A., Mclaren, J.S., Madl, R.L., Tuinstra, M., Lenz, M., Wang, D. 2007. Factors impacting ethanol production from grain sorghum in the dry-grind process. Cereal Chemistry. 84(2):130-136. Interpretive Summary: Sorghum is a drought and heat tolerant grain with starch content similar to that of maize. Currently about 5 to 15% of the U.S. sorghum crop goes towards the production of fuel ethanol. In order to improve the production of fuel ethanol from sorghum, the goal of this research is to understand the key factors impacting ethanol production from grain sorghum. Major factors related to higher ethanol production from sorghum included high starch content, rapid liquefaction, and low viscosity during liquefaction. Understanding the factors that can lead to improved ethanol production from sorghum may lead to ways the ethanol process can be altered to improve ethanol yields from sorghum and help sorghum breeders identify sorghum germplasm specifically for ethanol production.
Technical Abstract: The goal of this research is to understand the key factors impacting ethanol production from grain sorghum. Seventy genotypes and elite hybrids, with a range of chemical compositions and physical properties selected from approximately 1200 sorghum lines, were evaluated for ethanol production, and were used to study the relationships among composition, grain structure, and physical features that affect ethanol yield and fermentation efficiency. Variations of 22% in ethanol yield and 9% in fermentation efficiency were observed among the 70 sorghum samples. Genotypes with high and low conversion efficiencies were associated with attributes that may be manipulated to improve fermentation efficiency. Major characteristics of the elite sorghum genotypes for ethanol production by the dry-grind method include high starch content, rapid liquefaction, low viscosity during liquefaction, high fermentation speed, and high fermentation efficiency. Major factors adversely affecting the bioconversion process are tannin content, low protein digestibility, high mash viscosity, and an elevated concentration of amylose-lipid complex in the mash.