Phytate, the principal storage form of phosphorus in corn, is found to remain as a significant portion of phosphorus in the corn-ethanol coproducts streams. This poses concerns over poor digestion of these coproducts by monogastric animals and subsequent environmental issues on phosphorus. An ion-exchange-based process was developed to extract the phytate from thin stillage, which was selected as the influent based on the inositol phosphate distribution conducted on different corn-ethanol coproducts. Commercial industrial resins (IRA-93, IRA-68, IRA-900, IRA-400, and IRA-402) were characterized and screened for the phytate adsorption, specificity and capacity. Different types of eluents (NaOH, NaCl, NaHCO3, HCl, and NH4OH) were tested to evaluate the desorption capacity in all the six resins. Phytate-P isotherms and kinetics of the adsorption process, breakthrough profile on IRA-900 column and phytate elution curves were presented. This process yields a phytate-rich solution (11 g L-1), which is 25-fold concentrated compared to the concentration in thin stillage. The results show that the proposed retrofit process allows to leverage the existing corn-ethanol plants for high-value phytate production.
Bibliographical noteFunding Information:
University of Minnesota MnDRIVE Global Food Venture program; Reis's research is partially supported by University of Minnesota MnDRIVE-UMII Fellowship program; Reis's research is supported by CAPES, Ministry of Education, Brazil, under grant number 13252/13-5.