full issue - Association of Biotechnology and Pharmacy

Current Trends in Biotechnology and Pharmacy
Vol. 5 (3) 1298 -1308 July 2011, ISSN 0973-8916 (Print), 2230-7303 (Online)
1298
Improvement of rCHO Cell Density and Heterologous Protein
Production: Effect of Culture Conditions
M. Shakibaie 1,2 , F. Tabandeh 1* , A. Zomorodipour 3 , S. Ebrahimi 2 , F. Ataie 3 and
H. Habib Ghomi 1
1
Department of Industrial and Environmental Biotechnology, National Institute of Genetic Engineering and
Biotechnology, P.O. Box: 14965-161, Tehran, Iran
2
Biotechnology Group, Chemical Engineering Faculty, Sahand University of Technology, Tabriz, Iran
3
Department of Molecular Genetics,
National Institute of Genetic Engineering and Biotechnology, P.O. Box: 14965-161, Tehran, Iran
* For Correspondence - taban_f@nigeb.ac.ir
Abstract
Physico-chemical parameters have a great
impact on mammalian cell growth. In this study,
the effects of a number of amino acids,
precursors, serum, glucose, osmolality and
temperature on the recombinant Chinese hamster
ovary (rCHO) cells producing the recombinant
human coagulation factor VIII (rhFVIII) were
investigated, so as to improve the rCHO cell
density in the packed-bed bioreactor. The results
showed that while the concentration of
ammonium, as the main by-product, increased
by more than 6mM, the rCHO cell density
decreased significantly. On the other hand,
adding certain amino acids and precursors
mitigated the stress caused by ammonium and
consequently increased cell density. Proline and
glycine increased cell density up to
approximately 28% in comparison with the
negative control. Nucleic acids, as the main
precursors, had a significant impact on rCHO
cell growth, which increased by up to 20%.
Higher amounts of glucose (3.5 g/l) supplied the
carbon and energy requirements of the cells,
inhibited by-products formation and sequentially
increased heterologous protein production. The
precursors allowed a 14% improvement in
rhFVIII activity at high glucose concentrations,
which was 1.5 fold greater than the negative
control. Both hyperosmotic pressure and
temperature downshifts had remarkable adverse
effects on the rCHO cell density,; being reduced
to 2.7×10 6 cells/ml. The acquired suitable culture
conditions were applied to the packed-bed
bioreactor, and consequently an rCHO cell
density of 18×10 8 cells/l was achieved during
120 h of cultivation. The results of this study
indicated that the rCHO cells essentially need
supplementary materials to deal with
inappropriate culture conditions; especially in a
serum-free medium.
Keywords: Factor VIII, Packed-bed bioreactor,
Recombinant CHO cells, Serum-free medium.
Introduction
Mammalian cell cultures are necessary for
production of glycosylated recombinant
pharmaceutical proteins (1). Generally,
mammalian cells have low productivity,
Effect of culture conditions on rCHO cell growth