Abstract
Granulocyte-macrophage colony stimulation factor (GM-CSF) is a cytokine that stimulates the production of granulocytes, macrophages and white blood cells. Production of recombinant hGM-CSF was studied in rice cell secretory expression systems. In rice cell suspension culture, we used a rice amylase expression system in which the promoter RAmy3D is induced to express hGM-CSF by sucrose starvation. The drawback of this system is that the cells have to synthesize the recombinant protein without a carbon source, and thus improvements of culture condition for the recombinant protein production are desire to increase its productivity by addition of alternative carbon sources, such as succinic acid, pyruvic acid, malic acid, and fumaric acid. In addition, the viability of rice cells were higher. Succinic acid was the most effective alternative carbon source for the production of hGM-CSF. The accumulated hGM-CSF in the medium containing 80 mM succinic acid reached 165 mg/L at 15 days in batch culture while that in the control medium was 120 mg/L. These results show that the hGM-CSF prouctivity was increased from 12.8 % to 35.4 % by supplying the alternative carbon sources.
