Document Type: Research Paper
Biotechnology Group, Chemical Engineering Department, Engineering Faculty, Tarbiat Modarres University, P.O. Box 14155-143, Tehran, I.R. Iran.
Neuroscience Research Center, Shaheed Beheshti University, P.O. Box: 19835- 181. Tehran, I.R. Iran.
A simple fed-batch process with pre-determined exponential feeding strategy for high-cell-density cultivation
of recombinant E. coli BL21 (DE3) in defined medium was developed. In this feeding method glucose and
glycerol were used as the sole sources of carbon and energy to increase the cell density exponentially at
controlled specific growth rates, which do not cause the accumulation of acetate. Thus, sophisticated feedback
control or extra equipment to prevent the accumulation of toxic level of acetate is not necessary. The
final cell densities of 100 and 118 gl-1 of dry cell mass for recombinant E. coli producing human interferon-γ
(hIFN-γ) were obtained by using glucose and glycerol, respectively. The concentration of acetate was always
maintained below toxic level. The specific yield of hIFN-γ with glucose and glycerol was 93 and 92 mgg-1
of dry cell mass, and the overall productivity of hIFN-γ was 0.16 and 0.14 gl-1h-1 for these two carbon sources, respectively.