A comparison between corn and grain sorghum fermentation rates, Distillers Dried Grains with Solubles composition, and lipid profiles

- Grain sorghum and corn fermentations are evaluated and compared.
- Protease addition increases ethanol yields 1-2% for conventional fermentations.
- Lipid profiles in corn and sorghum DDGS are studied.
- Free fatty acids were significantly higher in sorghum DDGS relative to corn.

The aim of this study was to determine if the compositional difference between grain sorghum and corn impact ethanol yields and coproduct value when grain sorghum is incorporated into existing corn ethanol facilities. Fermentation properties of corn and grain sorghum were compared utilizing two fermentation systems (conventional thermal starch liquefaction and native starch hydrolysis). Fermentation results indicated that protease addition influenced the fermentation rate and yield for grain sorghum, improving yields by 1-2% over non-protease treated fermentations. Distillers Dried Grains with Solubles produced from sorghum had a statistically significant higher yields and significantly higher protein content relative to corn. Lipid analysis of the Distillers Dried Grains with Solubles showed statistically significant differences between corn and sorghum in triacylglycerol, diacylglycerol and free fatty acid levels.