(467f) Integrated Production of Succinic Acid with the Separative Bioreactor

Ion-exchange resins (IXR) have been widely used by industry for catalysis as well as an absorbent for removal of dilute salts from process streams. Electrodeionization (EDI), a combination of ion-exchange resin technology and electrodialysis membrane separation, has further enhanced the utilization of IXR and can significantly reduce capital and operating costs compared to conventional ion-exchange column. Currently, commercial EDI processes are used primarily to produce ultra-pure water for the semiconductor and pharmaceutical industries. ANL researchers have successfully improved on conventional EDI technology by developing ?IXR wafers? to immobilize the IX resins into a porous substrate. The novel resin wafer (RW) enables application of EDI to a wider range of applications compared to conventional loose resin EDI processes. The resin wafer is a porous matrix of resin beads immobilized by polymer. Using this technology, ANL has developed several process implementations that take advantage of EDI for bioprocessing as well as bioconversion. The chemical industry is actively seeking bio-catalytic replacements for traditional chemical catalysis reactions. In most cases, separation represents a significant fraction of the overall cost of the process. Therefore, bio-catalytic process designs that focus on maximizing product concentration, limiting impurities, and reducing downstream processing steps are needed. To help meet these needs we developed the EDI Separative Bioreactor to integrate up-stream bioreactor and down-stream product separation into one unit. This membrane-based Separative Bioreactor enables simultaneous bio-catalytic production (fermentations or enzymatic reactions) of organic acids and immediate product separation. Direct capture of organic acid products from bio-transformations offers two immediate benefits: prevention of reactor acidification and avoidance of product inhibition. Argonne also observed that rapid organic acid capture during production offered a new way to control reactor pH without the addition of buffers for pH control. In this presentation, we will discuss an integrated separative bioreactor designed for pure succinic acid production. This system consist a CO2 capture reactor, a succinic acid fermentation and in-situ pure succinic acid recovery using resin-wafer electrodeionization (RW-EDI). The fermentation is setup in a temperature-controlled, stirred bioreactor using a succinic acid producing E.coli mutant developed at Argonne which converts glucose to succinic acid using one mole CO2 per mole of glucose to produce one mole of succinic acid and other products. CO2 is provided from the CO2 capture reactor in the form of carbonate which is formed by bubbling CO2 gas through a basic solution. This solution is used to neutralize the succinic acid fermentator and provide the CO2 for the reaction. The fermentation broth was constantly sent to the RW-EDI device to separate succinic acid from the solution and recycle the base to the CO2 capture reactor. This work was supported by DOE Office of Biomass Program.