Improving dry-fractionated corn fermentation by supplementation of corn germ meal and pasta mill feed from agro-food industries

Background and objectives: Separation of germ from corn using dry fractionation in modified dry-grind processes results in the sluggish and incomplete fermentation of remaining corn because of nutrient deficiency for yeast. This study investigated the use of two low-value co-products, germ meal from corn wet milling and mill feed from pasta manufacturing, as additives to improve the fermentation of corn grits. Findings: Addition of 5% germ meal or 2.5% mill feed in corn grits resulted in the complete (no residual glucose) and faster fermentation, compared to 4.3% residual glucose during fermentation of only corn grits. Final ethanol yield (0.51 L/kg) was about 22% higher compared to control (0.42 L/kg). Increase in supplementation (10% of grits) further increased the fermentation rates, however, led to similar final ethanol concentrations and ethanol yields. Conclusions: Both germ meal and pasta mill feed can improve fermentation rate and efficiency of dry-fractionated grits and avoid the need for expensive supplements or enzymes. Significance and novelty: This research provides an innovative solution to the challenge of inefficient fermentation of dry-fractionated corn and also identifies new potential market for two low-value co-products from the agro-food industries.