Physiological responses to mixing in large scale bioreactors
| Autor: | L. Boone, S. Hjort, Britta Jürgen, A. Manelius, Bo Xu, Laszlo Fuchs, Naruemol Noisommit-Rizzi, P. C. Friberg, Peter Neubauer, Peter Vrábel, G. Hamer, Harald Skogman, Frans W. J. M. M. Hoeks, Bjørn H. Hjertager, Alvin W. Nienow, Caroline M. McFarlane, Christian Trägårdh, A. Rozkov, H. Y. Lin, Matthias Reuss, Michael Hecker, G. Blomsten, R. G. J. M. van der Lans, Karel Ch. A. M. Luyben, Sven-Olof Enfors, Tamas Kovacs, Mehmedalija Jahic, Johan Revstedt, D. O'Beirne, Elke Krüger, Thomas Schweder, Christopher J. Hewitt |
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| Rok vydání: | 2001 |
| Předmět: |
Microbial metabolism
Gene Expression chemistry.chemical_element Bioengineering Biology complex mixtures Applied Microbiology and Biotechnology Oxygen chemistry.chemical_compound Bioreactors Escherichia coli Bioreactor Formate Anaerobiosis Biomass RNA Messenger Overflow metabolism Mixed acid fermentation Acetic Acid technology industry and agriculture General Medicine Metabolism equipment and supplies RNA Bacterial Glucose chemistry Biochemistry Genes Bacterial Fermentation Biophysics Biotechnology |
| Zdroj: | Journal of Biotechnology. 85:175-185 |
| ISSN: | 0168-1656 |
| DOI: | 10.1016/s0168-1656(00)00365-5 |
| Popis: | Escherichia coli fed-batch cultivations at 22 m3 scale were compared to corresponding laboratory scale processes and cultivations using a scale-down reactor furnished with a high-glucose concentration zone to mimic the conditions in a feed zone of the large bioreactor. Formate accumulated in the large reactor, indicating the existence of oxygen limitation zones. It is suggested that the reduced biomass yield at large scale partly is due to repeated production/re-assimilation of acetate from overflow metabolism and mixed acid fermentation products due to local moving zones with oxygen limitation. The conditions that generated mixed-acid fermentation in the scale-down reactor also induced a number of stress responses, monitored by analysis of mRNA of selected stress induced genes. The stress responses were relaxed when the cells returned to the substrate limited and oxygen sufficient compartment of the reactor. Corresponding analysis in the large reactor showed that the concentration of mRNA of four stress induced genes was lowest at the sampling port most distant from the feed zone. It is assumed that repeated induction/relaxation of stress responses in a large bioreactor may contribute to altered physiological properties of the cells grown in large-scale bioreactor. Flow cytometric analysis revealed reduced damage with respect to cytoplasmic membrane potential and integrity in cells grown in the dynamic environments of the large scale reactor and the scale-down reactor. |
| Databáze: | OpenAIRE |
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