The main objective of this operation is to estimate the time for loading a column, track recovery yield, and estimate the number and size of columns required (in Design Mode).
● Packed Bed Adsorption (PBA) Chromatography Procedure (Simplified)
The total binding capacity of the resin refers to all the compounds that bind to the resin. The binding capacity can be estimated experimentally or approximately estimated using Scopes' correlation, providing the molecular weight of the main components is known (Scopes, 1982; p.105, Fig. 5.3).
If Q is the volume of material processed by the column per plant batch time, n is the number of cycles per batch, Ci is the concentration of component i in the feed stream, Fi is the fraction of component i that binds to the resin, then the volume, V, of the column is:
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where k is the total number of components in the feed stream, ODF is the overdesign factor, and C is the binding capacity of the resin. When the column length is specified, the diameter is calculated by the following equation:
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If D > Dmax, then multiple columns are assumed in parallel. Similarly, the user may decide to fix the diameter and have the program calculate the length.
You can choose among four different options for specifying the loading flowrate: you can specify the feed’s linear velocity, or its volumetric flowrate, or its relative flowrate (in bed volumes) in the bed, or the empty bed contact time (the amount of time it takes for a feed volume of material to flow through an empty bed). Any variable that is not specified will be calculated by the program based on the following relations:
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The process time is calculated using the following equation:
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The feed volume in the above equation is expressed in ‘packed bed volumes’.
A column may be used to bind either product component(s) or impurity components (specified by the Resin’s Primary Function buttons on the Loading tab).
In the first case (retention of product components), for a component that binds to the resin its amount in the product stream is equal to its amount in the feed stream times its binding fraction and its elution yield. All components present in the feed stream, that do not bind to resin, exit into the waste stream. Also, all materials in the wash-regeneration-equilibration streams end up in the waste stream. For elution steps, the ‘Volume in Product Stream’ factor which is expressed in ‘Bed Volumes’ determines the fraction of an elution buffer that ends up in the product stream. The remaining exits in the waste stream.
In the case of impurity retention, the fraction of a component that does not bind to the resin ends up in the product stream. For the bound amount, a fraction equal to the elution yield ends up in the product stream. The remaining is sent to the waste stream.
The cost associated with resin replacement is estimated as for all consumables (see Consumables Cost). For resins that last several years, the user may decide to depreciate the first resin fill-in by checking the ‘Is First Resin capitalized’ check box in the equipment consumables tab.
1. R.K. Scopes (1987). Protein Purification, Springer-Verlag.
2. H. Johansson, M. Ostling, G. Sofer, H. Wahlstrom, and D. Low (1988). Chromatographic Equipment for Large-Scale Protein and Peptide Purification. in “Advances in Biotechnological Processes”, Vol. 8, Edited by: A. Mizrahi, Published by Alan R. Liss, Inc.
3. R.W. Yost, L.S. Ettre, and R.D. Conlon (1980). Practical Liquid Chromatography - An Introduction. The Perkin-Elmer Corporation.
The interface of this operation has the following tabs:
● Oper. Cond’s, see PBA Column Loading (Simplified): Oper. Conds Tab
● Labor, etc, see Operations Dialog: Labor etc. Tab
● Description, see Operations Dialog: Description Tab
● Batch Sheet, see Operations Dialog: Batch Sheet Tab
● Scheduling, see Operations Dialog: Scheduling Tab
