Genomic DNA causes membrane fouling during sterile filtration of cell lysates

During biopharmaceutical production, efficient removal of impurities via filtration is essential. It is desirable to achieve high filter capacities along with a high degree of clearance. However, the complexity of bacterial cell lysates makes it difficult to properly estimate the filtration behavior. Here we investigated how host cell-derived impurities impacted the performance of commercially available sterile filters, with a focus on characterizing the dsDNA-induced decrease of filter capacity. Pressure flow curves at a constant flow, combined with particle analytics (e.g., nanoparticle-tracking analysis), indirectly revealed that dsDNA had a major influence on rapid membrane fouling. The observed phenomenon was more pronounced when using filters with small pore sizes (<0.2 & mu;m). Filter capacity could be substantially increased by reducing the size of the present dsDNA fragments, or by decreasing the potential for dsDNA-driven electrostatic interactions with positively charged molecules. In general, our present findings highlight the importance of monitoring dsDNA even during the primary recovery of proteins in cell lysates.