Proso millet (Panicum miliaceum L.) fermentation for fuel ethanol production

The objective of this research was to determine the conversion efficiency of proso millet to ethanol compared to corn in a bench-scale dry-grind procedure. Seven proso millet cultivars and six advanced breeding lines containing waxy starch were fermented with Saccharomyces cerevisiae and ethanol production was compared with normal corn and “highly fermentable” corn. The highly fermentable corn exhibited the highest fermentation efficiency (97.0 ± 1.4%). Among proso millet lines, those with the highest fermentation efficiencies were: Huntsman (85.9 ± 0.6%), 172-2-9 (90.8 ± 0.2%), 172-2-13 (85.1 ± 2.5%), and 182-4-24 (84.7 ± 2.1). Waxy proso millet lines resulted in higher fermentation efficiencies than the non-waxy proso millet varieties containing normal starch (82.4 ± 5.5% vs. 75.5 ± 7.4%, respectively, p = 0.01). Proso millet distiller's dried grains with solubles (DDGS) contained more protein (26.6–33.4%) than the DDGS from corn (17.2–23.4%). These data indicate that proso millet exhibits promise as a feedstock for ethanol production, especially if breeding programs focus on selecting “highly fermentable” lines for advancement.

► Fermentation efficiency of proso millet ranged from 66.4 to 90.8%.
► Waxy proso millet exhibited higher fermentation efficiency than non-waxy.
► Proso millet exhibits promise as a feedstock for fuel ethanol production.