Volume 5 Supplement 8
Disposable bioreactors: from process development to production
© Polès-Lahille et al; licensee BioMed Central Ltd. 2011
Published: 22 November 2011
Single-use bioreactors are commonly used for seeding stainless steel bioreactors or for producing material. The profitability of these equipments has been well demonstrated on more that decade. But few data on its scalability have been published.
In 2010-2011, Merck Serono Biodevelopment performed a study in order to evaluate the performance of several disposable bioreactors. As different technologies and scales were available, this study compared the performance of several types of mixing in single-use bioreactors for process development and pilot scale production. In addition, the evaluation was performed for both seeding applications and for clinical material production.
Description of the different disposable bioreactors assessed.
Cultibag STR TM
Cultibag RM TM
Cultibag Orbital TM β-test
Pierre Guerin ATMI
2 x 3-blade segment impeller
Move back and forth
Minimum working volume
Maximum working volume
Micro or marcro sparger
Overlay + Sparger
Overlay + Sparger
pH regulation with carbon dioxide
Headspace or sparger
In order to compare the 5 different types of disposable bioreactors, a fed-batch process producing a highly glycosylated molecule was performed. The cell growth during the amplification phase was similar reflected by the doubling time of the cells. It was similar between traditional bioreactors (21h in 250L stainless steel seeding bioreactor) and disposable bioreactors (from 17h in the Nucleo and the Orbital to 19h in the STR)
This study was completed by a characterization of liquid/liquid and gas/liquid transfers inside each disposable bioreactor in order to estimate their potential in terms of cell culture.
These cells did not require a lot of oxygen. A low kLa (0.44h–1 in the Nucleo) was sufficient to run this process. The air-flow rates applied in the orbital shaking bioreactor during the process were defined according to Merck Serono Biodevelopment and supplier experience.
These flow rates should have been decreased as kLa was higher (3.6h-1) than in traditional bioreactors (2.6 h-1).
Mixing time was measured in phosphate saline buffer at the maximum working volume and the agitation speed applied during production process. Mixing time was measured by injecting concentrated sodium hydroxide from the top of the bag and from the bottom of the bag.
The Nucleo and the CellReady 3L system have classical probes, while the Orbital, the RM and the STR bioreactors have optical probes. Optical probes were more stable because they took a measure every five seconds. Classical probes were less stable and showed variations of around 0.03 pH unit even a few minutes after injection in the Nucleo. Nevertheless, mixing times on all disposable bioreactors (from 15s in CellReady 3L to 100s in Orbital) were higher than in traditional bioreactors (12s in 3.6L glass bioreactor to 28s in 1250L stainless steel bioreactor). For the STR, the mixing time was close to one minute, which is the recommended maximum for mammalian cell culture. The Orbital and the Nucleo had a mixing time below two minutes. Howerver, after sodium hydroxide injection, pH measured below or close to the final pH value. The disposable bioreactor which has a mixing time closest to traditional bioreactors is the CellReady 3L.
Finally, an evaluation grid was applied to choose the best disposable bioreactor. All these comparisons allowed Merck Serono Biodevelopment to come to a conclusion about disposable bioreactor use and on the scalability (up and down) of these disposable systems. It also enabled us to highlight critical points for disposable bioreactor implementation such as tubing size and length, use of disposable or reusable probes or factory.
This article is published under license to BioMed Central Ltd. This is an open access article distributed under the terms of the Creative Commons Attribution License (http://creativecommons.org/licenses/by/2.0), which permits unrestricted use, distribution, and reproduction in any medium, provided the original work is properly cited.