Effects of Modified Processes in Dry-Grind Ethanol Production on Phosphorus Distribution in Coproducts

Several technologies have been recently developed and applied in dry-grind corn ethanol plants in the United States, including oil extraction from thin stillage, anaerobic digestion of thin stillage for biogas production and water reuse, as well as phytase addition before the fermentation to degrade phytate and increase the ethanol yield. Herein we evaluated downstream samples from various stages in ethanol and coproduct production from four large, commercial, dry-grind ethanol facilities to determine the composition and distribution of inositol phosphate and develop a phosphorus mass balance. The most significant change in phosphorus distribution resulted from the addition of phytase to upstream and fermentation processes, which partially degraded organic phosphorus to reactive phosphorus. The discussion presented may facilitate the understanding of phosphorus flow within an ethanol plant, indicating fractions richer in phosphorus, indicating, for instance, potential extraction pools within the ethanol industry.