Research on the Expression of Non-Mitogenic Recombinant Human aFGF in Escherichia Coli

Objectives: In order to improve the expression ability of the non-mitogenic recombinant human acidic fibroblast growth factor(nrhaFGF), the plasmid stability of rhaFGF mutant gene bearing system Escherichia coli BL21(DE3) was investigated widely. Methods: through the screen of strain and medium, the synthetic YH medium was selected as the fermentation medium the plasmid segrative and structural stability and so on were all measured, then produced the nrhaFGF by the addition of ampcillin (Amp) upon induction before the centrifugation of the broth; at last changed the expression strength of beta-lactamases according to the code-bias and site-directed PCR technology. Results: the synthetic medium YH was selected as the fermentation broth for the E.coli expression system; it was found that the plasmid segrative stability was above 90% after 50 generation with no selective pressure,the expression level kept within 25% - 28%,and the 100% stability of PstI digestion graph showed a satisfied structural stability of the system. LB agar plates experiment revealed part of the reason why system lost expression ability during induction; the expression level was improved 13.68% through the centrifugation upon induction, and improved 25% under the condition of IPTG 0.3 mmol/L, Amp 50 mug/mL. Conclusion: the process established in this paper was simple and easy to scale up, and showed a distinct economic benefits.