Applications of MA to Preparative Bioseparations

MAs have been applied to a variety of applications.1,44 There are numerous examples in the literature for the use of MAs for affinity purification using a variety of ligands.7,10,45-48 Ion exchange is also well documented in the MA literature. Hydrophobic interaction and reverse phase separations are rela- 

Purification of Proteins on MA Case Study of Recombinant Vaccine Protein 

This purification was further optimized such that a wash of 50 m M salt removed the contaminants. The target molecule was eluted by a pH step to minimize diafiltration or dilution step. Complete elution was accomplished by 15 mM citrate, pH 6.0. 

Due to the high DNA and endotoxin levels a second Q-step was added as a safety net. The pH was adjusted to 4.7, such that the vaccine product would flow through while the DNA and endotoxins would be retained. The low pH allowed sequential adsorption onto a carboxyl (C) membrane (Sartorius Corp.). A stepwise citrate pH gradient showed elution of the product at pH 5.5 (Fig. 11). 

The DNA and endotoxin levels were monitored throughout the purification process (Fig. 12). The final optimized process was robust and able to handle variable levels of these contaminants. The process achieved a high level of purity (99%) with reasonable yields (68%). The pH shifts used in elution eliminated the need for time-consuming diafiltration steps. The entire purification was completed within approximately 75 min. It was found that this process could easily be modified to accommodate other similar recombinant proteins. This process could easily be scaled up. 

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