Anion Exchanger
This overview discusses the principles and processes of anion exchange for separating insulin esters from denatured proteins. The process utilizes charged resin beads in a column to facilitate the binding of insulin esters through electrostatic interactions. Impurities are eliminated through a washing phase, followed by elution, where changes in pH enable the release of purified insulin esters. Proposed design parameters for a continuous system are provided, highlighting the technical specifications, supplier options, and alternatives for elution techniques.
Anion Exchanger
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Presentation Transcript
Anion Exchanger Kristen Galea
Where Are We With in the Process? • Entering stream is concentrated with, insulin ester, and denatured proteins • This separation technique separates anionic insulin ester from denatured ester and proteins • Two streams leave process • Impurities • Insulin ester for hydrolysis reaction
Principles of Ion Exchange • Charged resin beads packed in a column • Proteins stick to resins by electrostatic interactions • If solution is below the isoeletric point of the protein, cation exchange will occur (protein will have net + charge) • If solution is above the isoeletric point of the protein, anion exchange will occur (protein will have net – charge)
Principles of Ion Exchange • Proteins will be exchanged with the free ion around the resin beads – binding will occur • Elution of protein involves a change in pH (or addition of a salt or solvent) • Changes the charge on the protein – release of the protein
Anion Exchange Resins • Insoluble polymeric beads • Manufactured by polymerization of styrene and divinylbenzene (DVB) • DVB acts as a crosslinking agent and without styrene would be water soluble • Active groups (+) are covalently attached to bead balanced by equivalent number of oppositely charged (-) free ions
Anion Exchanger • 3 steps to Anion Exchange • Binding • Wash • Elution
Anion Exchanger • Binding – inlet to column runs through • 100% of insulin esters bind to resin beads • Wash with NaOH/Water (high pH) several times • Removes everything except insulin ester • Elute column with NaOH/Water (pH close to pI of protein – 5.4) • Insulin ester changes from a negative charged to neutral • Released from beads – 90% yield
Anion Exchange • Elution process simultaneously replenishes the negatively charged free ions around the resin (OH-) • Purified insulin ester stream then undergoes hydrolysis • Multiple columns to make a continuous process
Proposed Design • Assumptions • Batch = 24 hours • Flow entering = 67.9 kg/h • Bed Capacity = 0.01 kg/L • Estimated Dimensions • Bed Volume = 300 L (selected) • Bed Diameter = 1.5 m • Bed Height = 0.17 m • Diameter larger than height of bed, to reduce pressure drop
Suppliers • Column • Difficult to find – must be custom made • Amersham Biosciences • Resin • Based on what is being removed • Must have high capacity to retain proteins
Suppliers • Resin • Amersham Biosciences – Source 15Q • Strong Anion Exchange resin • Good for protein separation • Problem • Binding Capacity: 4.5X10-3kg/L • Low flow rate
Alternatives • Different types of elution can be used, however, more sophisticated control systems must be used to ensure appropriate amount of protein is removed • More testing required for this process.
