Preliminary Study On Fermentation Conditions Of Recombinant Human Interleukin 11

The optimal fermentation conditions of the genetic engineering E. coli (pET32/IL-11/BL(DE)21) that expressed recombinant human interleukin-11 in the flask have been studied by orthogonal experiment design, including the components of culture medium (glucose, tryptone, yeast extract and pH), shaking speed, medium volume and inoculum concentration. The best condition for cell growth and expression of rh-11 is glucose 10g/L, tryptone 20g/L, yeast extract 10g/L, NaCl 10.0 g/L, KH₂PO₄ 6.0 g/L, K₂HPO₄ 3.5 g/L, MgSO₄ 3.5 g/L, inoculum concentration 10%, shaking speed 220r/min, medium volume 10% and induction time 4-5h. The results showed that acetic acid not only caused the cell growth rate decrease and a progreased lag time, but also seriously inhibited the expression of foreign gene. Based on these data, fed-batch culture was carried out on BiofloIII-5L automatic fermentor. The dissolved oxygen was maintained around 20%; the recombinant cells were harvested at 4h after induction of IPTG with three continuous batches. We got average cell biomass at about 55g/L(DCW) and the average recombinant human...