Harmonization and characterization of different single‐use bioreactors adopting a new sparger design

Abstract

In mammalian cell culture, single-use bioreactors are widely used. Different hardware designs are available, ranging from stirred tank reactors to wave mixed and cubical shaken systems. Unlike in stainless steel systems, where standards exist, in singleuse bioreactors aeration devices are often predefined by the supplier. While ring sparger systems are the gold standard in stainless steel bioreactors, not all singleuse bioreactors are available with ring spargers. In this study, a comprehensive characterization of two stirred tank single-use bioreactor systems (XDR TM from Xcellerex and S.U.B. from Thermo Scientific Hyclone) was performed under GMP conditions with 200/250 L and 1000 L bioreactors. Engineering facts like mass transfer rates for oxygen k L a o2 and carbon dioxide k L a CO2 as well as mixing number were evaluated. To achieve improved similarity in key engineering parameters and in consequence cell culture performance, the submerse aeration device of the S.U.B.(to date only open tube and frit) was remodeled resulting in a drilled hole sparger design. Results of the characterization showed that k L a o2 in the S.U.B. was enhanced from 8.5 h −1 to 11.5 h −1 at the maximum, and the k L a CO2 was very similar between both bioreactor types. Knowledge of the characterization data as well as improved oxygen transfer rate in the S.U.B. allows for an interchangeable usage of the two different single-use bioreactors.

A practical approach in bioreactor scale‐up and process transfer using a combination of constant P/V and vvm as the criterion

“…A few recent reports have shown that CO 2 transfer rate is dominated by gas throughput, and the improvement in CO 2 removal has to come from there. [19][20][21] Consistent with this is that the sparger hole size was found to have no significant effect on k L a CO2 from the evaluation of 10 mm, 100 mm, and 1 mm hole sizes. 18 CO 2 removal is significantly affected by the bubble saturation and total gas throughput of the system; and the rate of CO 2 transfer reduces with the increase in bioreactor scale, compared with the rate of O 2 transfer.…”

“…Limited CO 2 removal will occur in these bioreactors, and CO 2 will accumulate in the culture since the respiratory quotient [RQ = carbon dioxide evolution rate (CER)/oxygen uptake rate (OUR)] is close to unity. A few recent reports have shown that CO 2 transfer rate is dominated by gas throughput, and the improvement in CO 2 removal has to come from there . Consistent with this is that the sparger hole size was found to have no significant effect on from the evaluation of 10 µm, 100 µm, and 1 mm hole sizes .…”

Biological performance of two different 1000 L single‐use bioreactors applying a simple transfer approach

“…Results of this characterization are published in detail elsewhere [4]. The model liquid consisted of a 1 × PBS with an osmolarity of approximately 290 mOsm/kg and a pH of 7.25, 2 mL L −1 Simethicone solution (Medical Antifoam C emulsion, Dow Corning, Wiesbaden, Germany) and additionally 1 g/L Pluronic F68 (Kolliphor P 188, BASF, Ludwigshafen, Germany).…”

“…Hence, the results of the characterization study showed significant improvements, there were still slight remaining differences observed [4], which does not allow a one-to-one transfer, keeping simply the same operational protocol. Thus, most probably changes in the geometry and the relevant key engineering parameters of the different bioreactors will occur.…”

“…was adapted. Hence, the results of the characterization study showed significant improvements, there were still slight remaining differences observed [4], which does not allow a one-to-one transfer, keeping simply the same operational protocol.…”