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 cu ltures sparged with pure oxygen prevented the accumulation of CO2 in t he culture medium and enhanced the cell growth rate and maximum cell d ensities. The CO2 accumulated to a concentration of similar to 24 mM i n 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 th e Sf-9 and High Five cell lines from 38 to 22 h and from 46 to 22 h, r espectively. In addition, headspace purging increased the maximum cell densities obtained in the Sf-9 and High Five cell cultures from simil ar to(5-6) to similar to(8-10) x 10(6) cells/mL and from similar to(3- 5) to similar to(8-10) x 10(6) cells/mL, respectively.