Constant volume diafiltration (CVD) is commonly used in the biopharmaceutical industry for impurity removal or buffer exchange. The number of diavolumes is usually determined empirically or by theoretical analysis to achieve the target degree of impurity removal. There is, however, a lack of conclusive information about the effect of contaminant removal in variable volume diafiltration (VVD). VVD can occur when the diafiltration control mode is not functioning as intended. In this study, a mathematical model has been proposed to predict removal efficiency during VVD. Experiments were performed to compare the results to model calculations. A dilute concentration of bovine serum albumin solution was used as the feed solution to study variable volume effects.
Tag: <span>diafiltration</span>
Microbial fermentation is used to produce such products as therapeutic proteins, antibiotics, hormones, enzymes, amino acids, blood substitutes and alcohol. These products may be expressed by the microbial cells themselves, expressed intracellularly in the cytoplasm or, in the case of bacterial cells, in the periplasmic material. Before any intracellularly-produced molecules can be used and further purified, the cells (i.e., E. coli) must be concentrated and set in an appropriate buffer (cell washing) before being lysed. Then after lysis, molecules of interest have to be separated from the parent cells and then clarified to remove cellular debris and other contaminants. Depending on the process used, additional clarification steps may be necessary…