title: Evaluation of the effects and interactions of mixing and oxygen transfer on the production of Fab' antibody fragments in Escherichia coli fermentation with gas blending.
abstract: Fermentations carried out at 450-L and 20-L scale to produce Fab' antibody fragments indicated a serious problem to control levels of dissolved oxygen in the broth due to the large oxygen demand at high cell densities. Dissolved oxygen tension (DOT) dropped to zero during the induction phase and it was hypothesised that this could limit product formation due to inadequate oxygen supply. A gas blending system at 20-L scale was employed to address this problem and a factorial 2(2) experimental design was executed to evaluate independently the effects and interaction of two main engineering factors: agitation rate and DOT level (both related to mixing and oxygen transfer in the broth) on Fab' yields. By comparison to the non-gas blending system, results in the gas blending system at same scale showed an increase in the production of Fab' by 77% independent of the DOT level when using an agitation rate of 500 rpm level and by 50% at an agitation rate of 1,000 rpm with 30% DOT. Product localisation in the cell periplasm of >90% was obtained in all fermentations. Results obtained encourage further studies at 450-L scale initially, to evaluate the potential of gas blending for the industrial production of Fab' antibody fragments.
authors.affiliation: The Advanced Centre for Biochemical Engineering, Department of Biochemical Engineering, University College London, Torrington Place, London, WC1E 7JE, UK.
authors.forename: Roeb
authors.initials: R
authors.lastname: García-Arrazola
authors.affiliation: The Advanced Centre for Biochemical Engineering, Department of Biochemical Engineering, University College London, Torrington Place, London, WC1E 7JE, UK.
authors.forename: Pierre
authors.initials: P
authors.lastname: Dawson
authors.affiliation: The Advanced Centre for Biochemical Engineering, Department of Biochemical Engineering, University College London, Torrington Place, London, WC1E 7JE, UK.
authors.forename: Ian
authors.initials: I
authors.lastname: Buchanan
authors.affiliation: The Advanced Centre for Biochemical Engineering, Department of Biochemical Engineering, University College London, Torrington Place, London, WC1E 7JE, UK.
authors.forename: Billy
authors.initials: B
authors.lastname: Doyle
authors.affiliation: Department of Statistical Science, University College London, Gower Street, London, WC1E 6BT, UK.
authors.forename: Tom
authors.initials: T
authors.lastname: Fearn
authors.affiliation: The Advanced Centre for Biochemical Engineering, Department of Biochemical Engineering, University College London, Torrington Place, London, WC1E 7JE, UK.
authors.forename: Nigel
authors.initials: N
authors.lastname: Titchener-Hooker
authors.affiliation: The Advanced Centre for Biochemical Engineering, Department of Biochemical Engineering, University College London, Torrington Place, London, WC1E 7JE, UK. f.baganz@ucl.ac.uk.
authors.forename: Frank
authors.initials: F
authors.lastname: Baganz
mesh_terms: D000911:Antibodies, Monoclonal / Q000096:biosynthesis / Q000235:genetics; D001693:Biological Transport, Active / Q000502:physiology; D019149:Bioreactors / Q000382:microbiology*; D049109:Cell Proliferation; D003198:Computer Simulation; D004926:Escherichia coli / Q000235:genetics / Q000378:metabolism*; D005740:Gases / Q000378:metabolism; D006801:Humans; D007140:Immunoglobulin Fab Fragments / Q000096:biosynthesis* / Q000235:genetics; D044085:Microfluidics / Q000379:methods*; D008954:Models, Biological; D010100:Oxygen / Q000378:metabolism*; D010101:Oxygen Consumption / Q000502:physiology*; D015202:Protein Engineering / Q000379:methods*; D011994:Recombinant Proteins / Q000096:biosynthesis
chemical_list: D000911:Antibodies, Monoclonal; D005740:Gases; D007140:Immunoglobulin Fab Fragments; D011994:Recombinant Proteins; D010100:Oxygen