Mass Production of Mammalian Cells under Chemostat Cultivation

동물세포의 연속 대량생산에 관한 연구

Cell density was gradually decreased as the dilution rate was increased under chemostat cultivation of HeLa cells. Maxium cell density was maintained at the dilution rate of 0.020 (1/h) which was far less than the wash-out rate of 0.050 (1/h), Maxium cell productivity of 2 (mL of cells/L/h)was obtained at the dilution rate of 0.030 (1/h) by showing the culture also required maintenance period at low dilution rates, whose result meant the deviation of continuous culture theroy. Methods of indirectly measuring cell density have been introduced to represent mammalian cell growth, which are packed cell volume and oxygen uptake rate, and these values showed good linear relationship with actual cell density by having correlation factor of 0.90. Theoretical maximum oxygen yield, $Y_{O2}^{max}$ and maintenance oxygen consumption rate, m$_{O2}$, were estimated as 4.1$\times$10$^5$ (cells/mmole $O_2$) and 10.71$\times$10$^{-9}$ (mmole $O_2$/cells/h) by employing oxygen yield model.

HeLa 세포주의 연속 배양시 세포수가 배지의 이동속도가 증가함에 따라 감소하는 현상을 나타냈으며, 최대 세포수를 유지할 때의 dilution rate은 0.012(1/h)로 wash-out인 0.050(1/h)보다 극히 낮으며, dilution rate이 0.030(1/h)일 때 2.0(mL of cells/L/h)의 최대 세포 생산속도를 보였다. 또한 낮은 배지 이동속도에서 세포수의 감소에 따른 maintenance term의 존재를 확인했다. 더불어 packed cell volume파 산소소비속도의 측정값이 실제 세포증식과 밀접한 관계가 있음이 입증되어 간접방법에 의한 생육도치 측정이 가능하게 되었다. 또한 산소 yield model에 의해 최대 산소 수율, $Y_{O2}^{max}$과 maintenance 산소소비속도, m$_{O2}$가 각각 4.1$\times$$10^5$(cells/mmole $O_2$)와 10.71$\times$$10^{-9}$(mmole $O_2$/ cells/h)로 측정되었다.