Expression of recombinant human insulin precursor by Pichia pastoris in a 10 liter bioreactor

Abstract

Recombinant insulin is a vital medicine for diabetic patients. This hormone is produced by microbes such as Pichia pastoris that carry the recombinant gene of a human insulin precursor (HIP). Large-scale protein production involves a bioreactor to promote the optimal condition for the yeast to express the protein target. In order to obtain a large amount of insulin, the cultivation of recombinant P.pastoris/pD902-IP carrying human insulin precursor gene in a bioreactor 10 Liter was developed. The isolate was cultivated in a half concentration of basal salt media for 124.5 hours. Induction of the protein was done by continual methanol feeding. The fermentation condition was set to have a temperature at 28°C, agitation at 300 rpm, aeration at 2 L/min and a pH value of around 5. Dry cell weight (DCW) was measured, and HPLC quantified the content of HIP, glycerol and methanol. This work’s DCW and HIP concentrations were 46.5 g/L and 928 mg/L, respectively. The results can be higher by increasing the number of cells in the culture or extending the cultivation time so that the HIP concentration may exceed 1 g/L.