Metabolic profiling of Chinese hamster ovary cell cultures at different working volumes and agitation speeds using spin tube reactors

Culture systems based on spin tube reactors have been consolidated in the development of manufacturing processes based on Chinese hamster ovary (CHO) cells. Despite their widespread use, there is little information about the consequences of varying operational setting parameters on the culture performance of recombinant CHO cell lines. Here, we investigated the effect of varying working volumes and agitation speeds on cell growth, protein production, and cell metabolism of two clonally derived CHO cell lines (expressing an IgG1 and a "difficult-to-express" fusion protein). Interestingly, low culture volumes increased recombinant protein production and decreased cell growth, while high culture volumes had the opposite effect. Altering agitation speeds exacerbated or moderated the differences observed due to culture volume changes. Combining low agitation rates with high culture volumes suppressed growth and recombinant protein production in CHO cells. Meanwhile, high agitation rates narrowed the differences in culture performance between low and high working volumes. These differences were also reflected in cell metabolism, where low culture volumes enhanced oxidative metabolism (linked to a productive phenotype) and high culture volume generated a metabolic profile that was predominately glycolytic (linked to a proliferative phenotype). Our findings indicate that the culture volume influence on metabolism modulates the balance between cell growth and protein production, a key feature that may be useful to adjust CHO cells toward a more productive phenotype.