Soluble periplasmic production of human granulocyte colony-stimulating factor (G-CSF) in Pseudomonas fluorescens

Protein Expr Purif. 2011 Jul;78(1):69-77. doi: 10.1016/j.pep.2011.03.002. Epub 2011 Mar 17.


Cost-effective production of soluble recombinant protein in a bacterial system remains problematic with respect to expression levels and quality of the expressed target protein. These constraints have particular meaning today as "biosimilar" versions of innovator protein drugs are entering the clinic and the marketplace. A high throughput, parallel processing approach to expression strain engineering was used to evaluate soluble expression of human granulocyte colony-stimulating factor (G-CSF) in Pseudomonas fluorescens. The human g-csf gene was optimized for expression in P. fluorescens and cloned into a set of periplasmic expression vectors. These plasmids were transformed into a variety of P. fluorescens host strains each having a unique phenotype, to evaluate soluble expression in a 96-well growth and protein expression format. To identify a strain producing high levels of intact, soluble Met-G-CSF product, more than 150 protease defective host strains from the Pfēnex Expression Technology™ toolbox were screened in parallel using biolayer interferometry (BLI) to quantify active G-CSF binding to its receptor. A subset of these strains was screened by LC-MS analysis to assess the quality of the expressed G-CSF protein. A single strain with an antibiotic resistance marker insertion in the pfaI gene was identified that produced>99% Met-GCSF. A host with a complete deletion of the autotransporter-coding gene pfaI from the genome was constructed, and expression of soluble, active Met-GSCF in this strain was observed to be 350mg/L at the 1 liter fermentation scale.

MeSH terms

  • Animals
  • Biotechnology / methods*
  • Blotting, Western
  • Cell Line, Tumor
  • Cell Proliferation / drug effects
  • Chromatography, Liquid
  • Fermentation
  • Granulocyte Colony-Stimulating Factor / biosynthesis*
  • Granulocyte Colony-Stimulating Factor / genetics
  • Granulocyte Colony-Stimulating Factor / isolation & purification
  • Granulocyte Colony-Stimulating Factor / pharmacology
  • Humans
  • Kinetics
  • Mass Spectrometry
  • Mice
  • Molecular Weight
  • Periplasm / genetics
  • Periplasm / metabolism
  • Pseudomonas fluorescens / genetics*
  • Pseudomonas fluorescens / metabolism
  • Recombinant Proteins / biosynthesis*
  • Recombinant Proteins / genetics
  • Recombinant Proteins / isolation & purification
  • Solubility


  • Recombinant Proteins
  • Granulocyte Colony-Stimulating Factor