Electrochemical Recovery of Biomolecules in Redox-Mediated Electrodialysis Platform

In the chemical and biochemical manufacturing industry, the recovery and purification of organic species are amongst the most energy-demanding steps, due to the complexity of product streams, involving unreacted reactants, byproducts, inorganic salts along with the final products. 1, 2 Membrane-integrated electrochemical methods have garnered interest as promising candidates for selective recovery of organic molecules, such as whey protein from cheese whey waste. 3 Nonetheless, they still encounter a bottleneck in discriminating among charged species, primarily due to the lack of intrinsic ion selectivity on the ion-exchange membrane. 1, 4 Here, we demonstrate a layer-by-layer (LBL) functionalization method to control the membrane selectivity, enabling the recovery of organic acids from a multicomponent mixture within a redox-mediated electrodialysis platform. Tailoring the physicochemical properties of ion-exchange membranes through LBL approach enables complete retention of succinate, while enhancing the overall flux for inorganic ions. 1 This remarkable retention capability of the LBL membrane extends to mono- (pyruvate) and multivalent organic acids (succinate and citrate), highlighting the robustness of LBL membrane in recovering various organic species, regardless of their charges. Integration of functionalized membrane into the redox-mediated ED system facilitates the continuous enrichment of succinate with high energy efficiency and membrane stability compared to conventional electrodialysis system. Furthermore, we demonstrate continuous up-concentration of succinate in tandem with the partitioning of unreacted sugar and inorganic ions, paving the way for modular multicomponent separations in biomanufacturing processes. References 1. Kim, N.; Lee, J.; Su, X. Precision Tuning of Highly Selective Polyelectrolyte Membranes for Redox‐Mediated Electrochemical Separation of Organic Acids. Advanced Functional Materials 2023 , 33 (12), 2211645. 2. Kim, N.; Jeon, J.; Chen, R.; Su, X. Electrochemical separation of organic acids and proteins for food and biomanufacturing. Chemical Engineering Research and Design 2022 , 178 , 267-288. 3. Kim, N.; Jeon, J.; Elbert, J.; Kim, C.; Su, X. Redox-mediated electrochemical desalination for waste valorization in dairy production. Chemical Engineering Journal 2022 , 428 , 131082. 4. Kim, N.; Oh, W.; Knust, K. N.; Zazyki Galetto, F. b.; Su, X. Molecularly Selective Polymer Interfaces for Electrochemical Separations. Langmuir 2023 .