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Quantification of the transient and long-term response of Saccharomyces cerevisiae to carbon dioxide stresses of various intensities

Paper ID Volume ID Publish Year Pages File Format Full-Text
34437 45026 2014 11 PDF Available
Title
Quantification of the transient and long-term response of Saccharomyces cerevisiae to carbon dioxide stresses of various intensities
Abstract

•Steady state chemostat cultures were submitted to step-increases in the CO2 concentrations.•The transient and long-term responses were analyzed with a focus on the energetics.•Transient response to elevated CO2 led to increase in energy generation detrimental to biomass synthesis.•The YATP decreased proportionally with increasing dissolved CO2 concentrations.•Transient response to elevated CO2 implies storage sugar mobilization, cations uptake and excretion of ethanol and acetate.

Carbon dioxide (CO2) is a major compound of microbial metabolism both as a substrate and as a product but high dissolved carbon dioxide concentrations have long been known to affect yeast physiology.This work investigates the energetic aspects of the transient and long-term responses of yeast chemostat cultures submitted to different step-increases of the dissolved CO2 concentrations.It was demonstrated that a CO2 shift-up triggered a transient metabolic response characterized by an increase of the specific respiration rate (up to +37%), the mobilization of storage sugars, excretion of ethanol and acetate (up to 50 mg L−1) and by the uptake of potassium (+30 mM) and magnesium (+20 mM) ions. The energy generation by the yeast metabolism temporarily increased and a transient decrease in the biomass synthesis was observed. This short-term response was not dependent of the amplitude of the shift-up and could not be explained by pH homeostasis only. Moreover, on the long-run CO2 created an energy drain that was proportional to its concentration as the YATP value decreased from 12.7 gX moleATP−1 to 9.57 gX moleATP−1 when the dissolved CO2 concentration was increased from 1.4 mM to 17.09 mM. Succinate excretion was also observed for CO2 enriched cultures and its production rate was found proportional with increasing CO2 concentrations. Finally, we pointed out that yeast cells may adapt to high CO2 concentrations in the long-run.This work illustrates the regulation of physiologic and metabolic homeostasis of yeast cells when facing CO2 stress.

Keywords
Dissolved carbon dioxide; Saccharomyces cerevisiae; Carbon dioxide stress; Chemostat
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Quantification of the transient and long-term response of Saccharomyces cerevisiae to carbon dioxide stresses of various intensities
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Publisher
Database: Elsevier - ScienceDirect
Journal: Process Biochemistry - Volume 49, Issue 11, November 2014, Pages 1808–1818
Authors
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Subjects
Physical Sciences and Engineering Chemical Engineering Bioengineering
Get Full-Text Now
Don't Miss Today's Special Offer
Price was $35.95
You save - $31
Price after discount Only $4.95
100% Money Back Guarantee
Full-text PDF Download
Online Support
Any Questions? feel free to contact us