GROWTH KINETICS AND HUMAN GROWTH HORMONE PRODUCTION OF A HEAT- INDUCIBLE RECOMBINANTE CHERICHIA COLI DURING BATCH FERMENTATION

Document Type: Regular Paper

Authors

1 1National Research Center for Genetic Engineering and Biotechnology (NRCGEB), Tehran, I.R. of Iran

2 National Research Center for Genetic Engineering and Biotechnology (NRCGEB), Tehran, I.R. of Iran

3 Department of Chemical Engineering, Tarbiat Modarres University, Tehran, I.R. of Iran

Abstract

The batch fermentation production of human growth hormone (hGH) was studied in a new
recombinant Escherichia coli. The effect of different levels of dissolved oxygen and glucose
concentration on cell density and substrate utilization were evaluated. The results indicated that the
optimum level of dissolved oxygen was 25% of air saturation. The specific growth rate reached a
maximum for an optimal glucose concentration of 5 gl-1, the maximum yield was 0.58 gg-1 and glucose
was completely consumed after 10 hrs. The growth of recombinant E. coli on semi-defined and complex
media was compared. The results demonstrated that dry cell weight and maximum specific growth rate
were 2.35 gl-1 and 0.4 h-1 on a complex medium, respectively, but they were 3.3 gl-1 and 0.24 h-1 on
semi-defined medium. The plasmid stability and hGH production during batch fermentation were
investigated. The results suggested that the specific growth rate is the most important factor on hGH
production and should be investigated in fed batch cultivation to get high cell density.

Keywords