Model‐based workflow for scale‐up of process strategies developed in miniaturized bioreactor systems

Abstract

Miniaturized bioreactor (MBR) systems are routinely used in the development of mammalian cell culture processes. However, scale-up of process strategies obtained in MBR-to larger scale is challenging due to mainly non-holistic scale-up approaches. In this study, a model-based workflow is introduced to quantify differences in the process dynamics between bioreactor scales and thus enable a more knowledge-driven scaleup. The workflow is applied to two case studies with antibody-producing Chinese hamster ovary cell lines. With the workflow, model parameter distributions are estimated first under consideration of experimental variability for different scales. Second, the obtained individual model parameter distributions are tested for statistical differences.In case of significant differences, model parametric distributions are transferred between the scales. In case study I, a fed-batch process in a microtiter plate (4 ml working volume) and lab-scale bioreactor (3750 ml working volume) was mathematically modeled and evaluated. No significant differences were identified for model parameter distributions reflecting process dynamics. Therefore, the microtiter plate can be applied as scale-down tool for the lab-scale bioreactor. In case study II, a fed-batch process in a 24-Deep-Well-Plate (2 ml working volume) and shake flask (40 ml working volume) with two feed media was investigated. Model parameter distributions showed significant differences. Thus, process strategies were mathematically transferred, and model predictions were simulated for a new shake flask culture setup and confirmed in validation experiments. Overall, the workflow enables a knowledge-driven evaluation of scale-up for a more efficient bioprocess design and optimization.

Comparison of mechanistic and hybrid modeling approaches for characterization of a CHO cultivation process: Requirements, pitfalls and solution paths

“…The dataset used in this work was generated in different studies with suspension‐grown CHO DP‐12 cells producing an interleukin‐8 antibody. [ 5,33,34 ] Please see Möller et al. (2019) [ 33 ] for a detailed description of the experimental conditions, which are briefly summarized in the following.…”

“…The dataset used in this work was generated in different studies with suspension-grown CHO DP-12 cells producing an interleukin-8 antibody. [5,33,34] Please see Möller et al (2019) [33] for a detailed description of the experimental conditions, which are briefly summarized in the following. The cells were cultivated in chemically defined TC-42 medium (Xell AG, Germany) supplemented with 6 mmol l −1 glutamine, 0.1 mg l −1 LONG R3 IGF-1, and 200 nmol l −1 Methotrexate (all Sigma-Aldrich).…”

“…The mechanistic model used in this study was already applied in different studies. [5,[33][34][35] In brief, the unstructured model is based on the description of the main substrates glucose (c Glc ) and glutamine (c Gln ) as well as the main metabolic waste products lactate (c Lac ) and ammonium (c Amm ). By this, cell growth behavior is modeled (X t -total cell density, and X v -viable cell density) using kinetic parameters K S,i (i = Glc, Gln), a maximal growth rate (μ max ), a cell lysis constant (K Lys ) of dead cells, and a minimal (μ d,min ) and a maximal death rate (μ d,max ).…”

Scale‐down of CHO cell cultivation from shake flasks based on oxygen mass transfer allows application of parallelized, non‐invasive, and time‐resolved monitoring of the oxygen transfer rate in 48‐well microtiter plates

“…[ 25 ] Besides, model‐based workflows have been established to scale CHO cell cultivation from 24‐deep well plates to shake flasks. [ 26 …”

Construction of a novel kinetic model for the production process of a CVA6 VLP vaccine in CHO cells

“…This model-assisted method significantly reduced the number of experiments required compared with the traditional design of experiment and therefore reduced the cost and time. Moreover, kinetics-based models facilitate bioprocess scale-up (Arndt et al 2021 ) and improve the understanding of the production process (Luo et al 2021 ). Despite these benefits, no kinetic model is available for the VLP production process.…”