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Applied and Environmental Microbiology, July 2004, p. 4222-4229, Vol. 70, No. 7
0099-2240/04/$08.00+0     DOI: 10.1128/AEM.70.7.4222-4229.2004
Copyright © 2004, American Society for Microbiology. All Rights Reserved.

Osmotic Stress Response: Quantification of Cell Maintenance and Metabolic Fluxes in a Lysine-Overproducing Strain of Corynebacterium glutamicum

Cristian A. Varela, Mauricio E. Baez, and Eduardo Agosin*

Departamento de Ingeniería Química y Bioprocesos, Escuela de Ingeniería, Pontificia Universidad Católica de Chile, Santiago, Chile

Received 30 January 2004/ Accepted 31 March 2004

Osmotic stress diminishes cell productivity and may cause cell inactivation in industrial fermentations. The quantification of metabolic changes under such conditions is fundamental for understanding and describing microbial behavior during bioprocesses. We quantified the gradual changes that take place when a lysine-overproducing strain of Corynebacterium glutamicum is grown in continuous culture with saline gradients at different dilution rates. The use of compatible solutes depended on environmental conditions; certain osmolites predominated at different dilution rates and extracellular osmolalities. A metabolic flux analysis showed that at high dilution rates C. glutamicum redistributed its metabolic fluxes, favoring energy formation over growth. At low dilution rates, cell metabolism accelerated as the osmolality was steadily increased. Flexibility in the oxaloacetate node proved to be key for the energetic redistribution that occurred when cells were grown at high dilution rates. Substrate and ATP maintenance coefficients increased 30- and 5-fold, respectively, when the osmolality increased, which demonstrates that energy pool management is fundamental for sustaining viability.

* Corresponding author. Mailing address: Pontificia Universidad Católica de Chile, Casilla 306, Correo 22, Santiago 782-0436 M, Chile. Phone: 562 354 49 27. Fax: 562 354 58 03. E-mail: agosin{at}ing.puc.cl.

Applied and Environmental Microbiology, July 2004, p. 4222-4229, Vol. 70, No. 7
0099-2240/04/$08.00+0     DOI: 10.1128/AEM.70.7.4222-4229.2004
Copyright © 2004, American Society for Microbiology. All Rights Reserved.



This article has been cited by other articles:

  • Kromer, J. O., Bolten, C. J., Heinzle, E., Schroder, H., Wittmann, C. (2008). Physiological response of Corynebacterium glutamicum to oxidative stress induced by deletion of the transcriptional repressor McbR. Microbiology 154: 3917-3930 [Abstract] [Full Text]  


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