Bioreactor Headspace Purging Reduces Dissolved Carbon Dioxide Accumulation in Insect Cell Cultures and Enhances Cell Growth

Flushing the bioreactor headspace of Sf‐9 and High Five insect cell cultures sparged with pure oxygen prevented the accumulation of CO 2 in the culture medium and enhanced the cell growth rate and maximum cell densities. The CO 2 accumulated to a concentration of ∼24 mM in both cultures in the absence of headspace purging compared to levels of 3 and 6 mM in the purged Sf‐9 and High Five cultures, respectively. Headspace purging decreased the mean population doubling times of the Sf‐9 and High Five cell lines from 38 to 22 h and from 46 to 22 h, respectively. In addition, headspace purging increased the maximum cell densities obtained in the Sf‐9 and High Five cell cultures from ∼(5–6) to ∼(8–10) × 10 6 cells/mL and from ∼(3–5) to ∼(8–10) × 10 6 cells/mL, respectively.