title: Efficient process development of recombinant human granulocyte colony-stimulating factor (rh-GCSF) production in Escherichia coli.
abstract: The protein hormone granulocyte colony-stimulating factor (GCSF) stimulates the production of white blood cells and plays an important role in medical treatment of cancer patients.
  
  
  
  An efficient process was developed for heterologous expression of the human GCSF in E. coli BL21 (DE3). The feeding rate was adjusted to achieve the maximum attainable specific growth rate under critical value. In this method, specific growth rate was maintained at the maximum value of 0.55 h⁻¹ at the beginning of feeding to 0.4 h-1 at the induction time. Recombinant human GCSF (rh-GCSF) was produced as inclusion body. At first, inclusion bodies were released by cell disruption and then washed, solubilized and refolded. Finally, the rh-GCSF was purified by cation exchange chromatography.
  
  
  
  Obviouly, higher specific growth rate decreases process time and consequently increases productivity. The final concentration of biomass and GCSF was achieved 126 g DCW.l⁻¹ and 32.1 g.l⁻¹. Also, the final specific yield (YP/X) and total productivity of rh-GCSF were obtained 254 mg.g⁻¹ DCW and 1.83 g.l⁻¹.h⁻¹, respectively. According to the available data, this is one of the highest YP/X and productivity that has been reported for any human protein which is expressed in E. coli. Recovery yield of purification process was %40 and purity of recombinant protein was over than 99%. The circular dichroism spectra of purified rh-GCSF, Neupogen and PD-Grastim showed that all proteins have a similar secondary structure.
  
  
  
  Modified exponential feeding strategy for fed-batch cultivation of recombinant E. coli, results in minimum fed-batch duration and maximum productivity.
authors: Dept. of Bioscience and Biotechnology, Malek Ashtar University of Technology, P.O. Box 14395-1561, Tehran, Iran.
authors: Valiollah
authors: V
authors: Babaeipour
authors: Dept. of Biotechnology, Chemical Engineering Faculty, Tarbiat Modarres University, Tehran, Iran.
authors: Sirwan
authors: S
authors: Khanchezar
authors: Dept. of Biochemistry and Bioinformatics Research Center, School of Pharmacy and Pharmaceutical Science, Isfahan University of Medical Sciences, Isfahan, Iran.
authors: Mohammad Reza
authors: MR
authors: Mofid
authors: Dept. of Life Science Engineering, Faculty of New
   Technologies, University of Tehran, Tehran, Iran.
authors: Mahdi
authors: M
authors: Pesaran Hagi Abbas
mesh_terms: D002942:Circular Dichroism; D003001:Cloning, Molecular; D004926:Escherichia coli / Q000235:genetics* / Q000378:metabolism*; D016179:Granulocyte Colony-Stimulating Factor / Q000096:biosynthesis* / Q000235:genetics*; D006801:Humans; D011994:Recombinant Proteins / Q000096:biosynthesis* / Q000235:genetics / Q000378:metabolism
chemical_list: D011994:Recombinant Proteins; D016179:Granulocyte Colony-Stimulating Factor
keywords: Escherichia coli; Granulocyte colony-stimulating factor; Process development