ORIGINAL RESEARCH A test facility for fritted spargers of production-scale-bioreactors C. Sieblist • M. Aehle • M. Pohlscheidt • M. Jenzsch • A. Lu ¨bbert Received: 31 May 2010 / Accepted: 26 November 2010 / Published online: 12 December 2010 Ó Springer Science+Business Media B.V. 2010 Abstract The production of therapeutic proteins requires qualification of equipment components and appropriate validation procedures for all operations. Since protein productions are typically performed in bioreactors using aerobic cultivation processes air sparging is an essential factor. As recorded in literature, besides ring spargers and open pipe, sinter frits are often used as sparging elements in large scale bioreactors. Due to the manufacturing process these frits have a high lot-to-lot product variability. Expe- rience shows this is a practical problem for use in production processes of therapeutic proteins, hence frits must be tested before they can be employed. The circumstance of checking quality and performance of frits as sparging elements was investigated and various possibilities have been compared. Criteria have been developed in order to evaluate the sparging performance under conditions comparable to those in production bioreactors. The oxygen mass transfer coefficient (k L a) was chosen as the evaluation crite- rion. It is well known as an essential performance measure for fermenters in the monoclonal antibody production. Therefore a test rig was constructed able to automatically test frit-spargers with respect to their k L a-values at various gas throughputs. Performance differences in the percent range could be detected. Keywords Fritted spargers  Bubble aeration  Oxygen supply  Animal cell bioreactors Introduction Most production reactors for recombinant therapeutic glycoproteins are aerated stirred tanks where hosts such as Chinese Hamster Ovary Cells are grown in aerobic culture (Wlaschin and Hu 2006). In recent years nearly all of these cultures were aerated with air or an air/oxygen/carbon dioxide mix, dispersed into the culture by means of a sparger (Nienow 2006). Some reactor manufacturers prefer normal ring spargers with drilled holes, others simply use open tubes. Often, frit spargers (Gray et al. 1996), are used. All components in and around production bioreactors must be validated before they can be used in production, so the frit spargers. Here we are reporting about a test facility for frit sparger elements which are used in production scale bioreactors. We focus on the aeration characteristics of frit spargers. As the cell densities in production scale mammalian cell cultures are rather small (up to about 1.0 9 10 7 C. Sieblist  M. Aehle  A. Lu ¨bbert (&) Institute of Biochemistry and Biotechnology, Center for Bioprocess Engineering, Martin-Luther-University Halle-Wittenberg, Kurt-Mothes-Str. 3 / 320.2, 06120 Halle, Saale, Germany e-mail: Andreas.Luebbert@biochemtech.uni-halle.de C. Sieblist  M. Pohlscheidt  M. Jenzsch Roche Diagnostics GmbH, Nonnenwald 2, 82377 Penzberg, Germany 123 Cytotechnology (2011) 63:49–55 DOI 10.1007/s10616-010-9325-6