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Modeling large-scale bioreactors with diffusion equations. Part II: Characterizing substrate, oxygen, temperature, pH, and CO 2 profiles
  • Pauli Losoi,
  • Jukka Konttinen,
  • Ville Santala
Pauli Losoi
Tampereen yliopisto - Hervannan kampus

Corresponding Author:[email protected]

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Jukka Konttinen
Tampereen yliopisto - Hervannan kampus
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Ville Santala
Tampereen yliopisto - Hervannan kampus
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Large-scale fermentation processes involve complex dynamic interactions between mixing, reaction, mass transfer, and the suspended biomass. Empirical correlations or case-specific computational simulations are usually used to predict and estimate the performance of large-scale bioreactors based on data acquired at bench scale. In this two-part-study, one-dimensional axial diffusion equations were studied as a general and predictive model of large-scale bioreactors. This second part focused on typical fed-batch operations where substrate gradients are known to occur, and characterized the profiles of substrate, pH, oxygen, carbon dioxide, and temperature. The physically grounded steady-state axial diffusion equations with first- and zeroth-order kinetics yielded analytical solutions to the relevant variables. The results were compared with large-scale Escherichia coli and Saccharomyces cerevisiae experiments and simulations from the literature, and good agreement was found in substrate profiles. The analytical profiles obtained for dissolved oxygen, temperature, pH, and CO 2 were also consistent with the available data. Distribution functions for the substrate were defined, and efficiency factors for biomass growth and oxygen uptake rate were derived. In conclusion, this study demonstrated that axial diffusion equations can be used to model the effects of mixing and reaction on the relevant variables of typical large-scale fed-batch fermentations.
21 Jul 2023Submitted to Biotechnology and Bioengineering
21 Jul 2023Assigned to Editor
21 Jul 2023Submission Checks Completed
21 Jul 2023Review(s) Completed, Editorial Evaluation Pending
25 Aug 2023Reviewer(s) Assigned
30 Oct 2023Editorial Decision: Revise Major