Congratulations to KGI's team at the Amgen Bioprocessing Center on successfully completing a landmark bioreactor study demonstrating bubble-free oxygenation using a silicone membrane gas exchanger as an alternative to conventional bubble sparging. The KGI team included David Guthary, PhD candidate; and Shiva Abdolrahimi, Assistant Professor of Bioprocessing.
The study demonstrated that a 0.5-m² silicone membrane gas exchanger could provide sufficient oxygen transfer to meet the metabolic demands of a 1.8-L CHO cell culture while maintaining dissolved oxygen (DO) control without bubble sparging. Under the conditions evaluated, the membrane gas exchanger supported oxygen transfer performance comparable to or exceeding that achieved with conventional bubble sparging.
The cell culture run was initiated using conventional bubble sparging with the gas exchanger loop clamped off, thereby preventing cells from circulating through the membrane gas exchanger (PermSelect - 5000 LD) and the centrifugal pump (Levitronix DCP-200.3).
A target DO of 40% was maintained using an Applikon DCU (ez-Control) with a constant air supply and variable supplemental oxygen. After the viable cell density (VCD) reached 5.8 million cells/mL, bubble sparging was discontinued. Oxygenation was then maintained exclusively through the membrane gas exchanger by switching the gas supply to the exchanger, opening the recirculation loop, and initiating flow with the centrifugal pump.
The culture reached a peak VCD of 23.3 million cells/mL on Day 9—approximately 16% higher than previously achieved at the facility for this CHO cell line using conventional bubble sparging.
This study establishes practical start-up and operating guidelines for implementing bubble-free membrane gas exchange in mammalian cell culture bioreactors and demonstrates its potential as an alternative oxygenation strategy for upstream bioprocessing.
Organizations interested in advancing upstream bioprocessing technologies are encouraged to connect with MedArray and KGI to explore how bubble-free membrane gas exchange can enhance upstream bioprocess performance.
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