Viral Bioprocessing

Regulators have imposed limits on the amount and length of DNA residues in final dosages for human administration, and viral vector manufacturers therefore seek to minimize DNA impurities (typically host-cell DNA and plasmids from transfection) in the final product. The industry standard for removing residual DNA is to use a bioprocessing-grade nuclease in the downstream process.

The conditions for the nuclease treatment vary across vectors, serotypes and media, and also due to downstream considerations. In some cases, typically with fragile enveloped vectors such as lentivirus, digestion of DNA under close to physiological conditions is preferred. When manufacturing more robust vectors such as AAVs, the downstream process can benefit from a higher salt concentration. Due to the high surface charge of some viral capsids, they can show a tendency to associate with residual DNA. This results in aggregation, which ultimately reduces the viral titer. Using a high salt buffer can reduce the affinity of capsids to DNA and thus also the viral aggregation. An additional benefit of increasing the salt concentration is that it makes the chromatin-DNA more accessible for digestion by similar mechanisms.

Several commercially available endonucleases used for DNA removal in bioprocessing originate from Serratia marcescens. These nucleases do not perform optimally at the physiological conditions found in cell media, nor do they tolerate high salt concentrations. The conditions in many conventional viral vector manufacturing processes, inhibits the activity of the nucleases. To compensate for the loss of activity, a possible solution is to adapt the workflow to the nuclease (e.g by introducing a desalting step), or to increase the amount of nuclease used. By instead using nucleases that are tailor made for viral bioprocessing, this can result in a less expensive and more efficient process.

Our bioprocessing grade nucleases are manufactured using only non-animal and non-plant origin raw materials to minimize the risk of contamination with adventitious agents and allergens. The final product is sterile filtered (0.22 μm), and release tests include both bioburden and endotoxin assays according to USP-harmonised European Pharmacopeia methods.

By being the original manufacturer of SAN HQ and M-SAN HQ, we offer full traceability of the supply chain and manufacturing process. We also assist our clients in implementing identity and quality assays in-house.

We believe by this approach ArcticZymes Technologies offers an attractive balance between quality and cost for their customers.

SAN High Quality® is the ultimate solution for efficient removal of nucleic acids in high-salt manufacturing and bioprocessing workflows. This non-specific endonuclease has optimum activity at salt concentrations between 400 – 600 mM, allowing significant improvements in efficiency and yield. SAN High Quality is also used to eliminate exogenous DNA contamination for in-process qPCR titer measurements. Following the efficient contamination clearance, the nuclease can easily be inactivated at PCR-friendly conditions. Viral DNA is protected by capsids, and remains intact also after the viral lysis.

M-SAN High Quality® is a novel, nonspecific endonuclease with excellent performance at physiological conditions found in typical cell media. M-SAN HQ outperforms other commercially available nucleases in removal of DNA impurities at conditions often used for manufacture of fragile viral vectors such as lentiviruses.