Genetic Engineering & Biotechnology News

SEP15 2017

Genetic Engineering & Biotechnology News (GEN) is the world's most widely read biotech publication. It provides the R&D community with critical information on the tools, technologies, and trends that drive the biotech industry.

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Genetic Engineering & Biotechnology News | GENengnews.com | SEPTEMBER 15, 2017 | 23 quent careful design, of unit operations that assure the desired purity. On the other hand, a surge tank can improve process robustness. Surge tanks are added to a process sequence to reduce variation in the composition of the prod- uct stream and/or to allow for introduction of extra pumps if other pumps upstream are not powerful enough to deliver an uninterrupted flow through several unit operations (e.g., chro- matography steps connected in series). How- ever, if a chromatography step is operated in the bind-and-elute mode, where composition dur- ing the elution stage changes … This variation in product concentration may or may not in- fluence the performance of the subsequent unit operation. Usually it does not, but if it does, a surge tank can help eliminate this effect. In the case of chromatography steps oper- ated in flow-through mode, a surge tank is not needed, unless a significant adjustment of the stream compositions (pH/salt) is needed. And even then, commercially available technolo- gies for in-line adjustment of pH or conductiv- ity can be used instead. Some could argue that surge/break-up tanks can be used as intermedi- ate quarantine tanks as part of the process con- trol strategy if a deviation occurs. From that perspective, it would probably be more advan- tageous to have standby tanks that are not part of a normal operation. to variations in productivity of other unit operations either upstream or downstream. Also, they might have some utility as draw points in moni- toring product quality management. Engineered properly, a continuous production scheme should not need surge tanks. Andrew Zydney (Penn State University): Surge tanks can be a very appropriate way to handle process disruptions in a fully continuous manufacturing line. All processes/unit operations require some maintenance (e.g., replacement of membranes in a filter module). A properly designed surge tank would allow the rest of the process to contin- ue to run while an operator replaced or cleaned the membranes. In addi- tion, surge tanks can help manage fluctuations in flow rate and product concentrations. This is particularly important when using processes that operate in a cyclic fashion (e.g., mul- ticolumn chromatography systems), in which the product flow rate and concentration vary with time over the cycle. The surge tank can effectively 'average out' these variations, provid- ing more effective operation of the subsequent downstream process. Dana Pentia (Repligen): In an ideal world, a surge tank will not be needed. 'Ideal world' implies that all the process steps are perfectly syn- chronized and controlled. However, if the process is not fully synchro- nized, controlled, and understood, a surge tank is needed as a link be- tween steps. Massimo Morbidelli (ETH Zürich): Surge tanks are mainly a safety mea- sure to ensure that the product qual- ity can be monitored between up- stream and downstream and that in case of downstream problems, not the entire batch was lost. It also al- lows for a better batch definition and to even out any variations in feed titer and quality, so that the Protein A cap- ture step can be run consistently with the same feed load, ensuring that the same yield and ratios of product to impurities are loaded. We have shown in a recent paper how the integration between these two units can operated so that any feed titer variation or Pro- tein A capacity decrease can be offset, ensuring a consistent process. Karol Lacki (Avitide): A surge tank is not a unit operation that is intro- duced to improve product quality and, therefore, it does not affect prod- uct safety. Product safety is secured through a right choice, and subse- Perspectives Bioprocessing © 2017 MaxCyte, Inc. All Rights Reserved. Accelerating Your Biotherapeutic Discovery, Development and Biomanufacturing From concept to care, our delivery platform for cell engineering helps you unleash the power of the cell. • Scalable transfection systems and scientific support to ensure your success • Delivery platform for CHO-based transient and stable protein production • The efficiency and viability you need from bench to clinic • Use any cell to identify the right candidate faster • Milligram to grams of protein from a single transfection • Trusted by 9 of the top 10 global pharmaceutical companies Any Cell. Any Molecule. Any Scale. ® Unleash your power: MaxCyte.com/accelerate-biotherapeutics

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