title: Influence of scale-up on the quality of recombinant human growth hormone.
abstract: The aerobic fed-batch production of recombinant human growth hormone (rhGH) by Escherichia coli was studied. The goal was to determine the production and protein degradation pattern of this product during fed-batch cultivation and to what extent scale differences depend on the presence of a fed-batch glucose feed zone. Results of laboratory bench-scale, scale-down (SDR), and industrial pilot-scale (3-m(3)) reactor production were compared. In addition to the parameters of product yield and quality, also cell yield, respiration, overflow, mixed acid fermentation, glucose concentration, and cell lysis were studied and compared. The results show that oxygen limitation following glucose overflow was the critical parameter and not the glucose overflow itself. This was verified by the pattern of byproduct formation where formate was the dominating factor and not acetic acid. A correlation between the accumulation of formate, the degree of heterogeneity, and cell lysis was also visualized when recombinant protein was expressed. The production pattern could be mimicked in the SDR reactor for all parameters, except for product quantity and quality, where 30% fewer rhGH-degraded forms were present and where about 80% higher total yield was achieved, resulting in 10% greater accumulation of properly formed rhGH monomer.
authors.affiliation: Centre for Bioprocess Technology, Department of Biotechnology, Royal Institute of Technology (KTH), SE-100 44 Stockholm, Sweden.
authors.forename: F
authors.initials: F
authors.lastname: Bylund
authors.forename: A
authors.initials: A
authors.lastname: Castan
authors.forename: R
authors.initials: R
authors.lastname: Mikkola
authors.forename: A
authors.initials: A
authors.lastname: Veide
authors.forename: G
authors.initials: G
authors.lastname: Larsson
mesh_terms: D019149:Bioreactors / Q000592:standards; D001709:Biotechnology; D004269:DNA, Bacterial / Q000378:metabolism; D004926:Escherichia coli / Q000235:genetics / Q000254:growth & development / Q000378:metabolism; D005947:Glucose / Q000378:metabolism; D006019:Glycolysis; D019382:Human Growth Hormone / Q000096:biosynthesis* / Q000235:genetics / Q000592:standards; D006801:Humans; D066298:In Vitro Techniques; D010865:Pilot Projects; D011786:Quality Control; D011994:Recombinant Proteins / Q000096:biosynthesis / Q000235:genetics / Q000592:standards
chemical_list: D004269:DNA, Bacterial; D011994:Recombinant Proteins; D019382:Human Growth Hormone; D005947:Glucose