Intracellular accumulation of ethanol in yeast
Ethanol produced in the course of a batch fermentation by Saccharomyces cerevisiae or added from the outside, affects adversely the specific rate of growth of the yeast population, its viability, its specific rate of fermentation, and the specific rates of the uptake of sugar and amino acids. The underlying mechanisms are many and include irreversible denaturation and hyperbolic noncompetitive inhibition of glycolytic enzymes, the exponential noncompetitive inhibition of glucose, maltose, and ammonium transport, the depression of the optimum and the maximum temperature for growth, the increase of the minimum temperature for growth, and the enhancement of thermal death and petite mutation. Nagodawithana and Steinkraus reported that added ethanol was less toxic for S. cerevisiae than ethanol produced by the yeast. The death rates were lower in the presence of added ethanol than those measured at similar external ethanol concentrations endogenously produced. They proposed that, due to an unbalance between the rates of production and the net outflux of ethanol, there would be an intracellular accumulation of ethanol which in turn would explain the apparently greater inhibitory potency of endogenously produced ethanol present in the medium. This hypothesis was supported by the findings of several authors who reported that the intracellular concentration of ethanol, in the course of batch fermentation, is much higher than its concentration in the extracellular medium. The present work is an attempt to clarify this matter. (Refs. 32).
- Research Organization:
- Lab. of Microbiology, Lab. of Physiology, Gulbenkian Inst. of Science, 2781 Oeiras Codex, Portugal
- OSTI ID:
- 5376901
- Journal Information:
- Biotechnol. Bioeng.; (United States), Vol. 25:9
- Country of Publication:
- United States
- Language:
- English
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Related Subjects
ETHANOL
BIOLOGICAL EFFECTS
UPTAKE
SACCHAROMYCES CEREVISIAE
GROWTH
BATCH CULTURE
ENZYMES
FERMENTATION
INHIBITION
ALCOHOLS
BIOCONVERSION
FUNGI
HYDROXY COMPOUNDS
MICROORGANISMS
ORGANIC COMPOUNDS
PLANTS
SACCHAROMYCES
YEASTS
560302* - Chemicals Metabolism & Toxicology- Microorganisms- (-1987)