Transport and intracellular accumulation of acetaldehyde in saccharomyces cerevisiae

• Published in: Biotechnology and bioengineering 1993-06, Vol.42 (1), p.24-29
• Main Authors: Stanley, G. A., Pamment, N. B.
• Format: Article
• Language: English
• Subjects: 09 BIOMASS FUELS; 560300 > Chemicals Metabolism & Toxicology; ACETALDEHYDE; ALCOHOLS; ALDEHYDES; BIOCONVERSION; BIOLOGICAL ACCUMULATION; Biological and medical sciences; Biology of microorganisms of confirmed or potential industrial interest; BIOSYNTHESIS; Biotechnology; CHROMATOGRAPHY; ETHANOL; EUMYCOTA; FERMENTATION; Fundamental and applied biological sciences. Psychology; FUNGI; GAS CHROMATOGRAPHY; GROWTH; HYDROXY COMPOUNDS; inhibition; intracellular accumulation; MEMBRANE TRANSPORT; MICROORGANISMS; Mission oriented research; ORGANIC COMPOUNDS; Physiology and metabolism; PLANTS; RADIATION, THERMAL, AND OTHER ENVIRON. POLLUTANT EFFECTS ON LIVING ORGS. AND BIOL. MAT; SACCHAROMYCES; SACCHAROMYCES CEREVISIAE; SEPARATION PROCESSES; SYNTHESIS; TOXICITY; transport; yeast; YEASTS 090900 > Biomass Fuels-- Processing-- (1990-)
• ISSN: 0006-3592; 1097-0290
• DOI: 10.1002/bit.260420104

The rate of acetaldehyde efflux from yeast cells and its intracellular concentration were studied in the light of recent suggestions that acetaldehyde inhibition may be an important factor in yeast ethanol fermentations. When the medium surrounding cells containing ethanol and acetaldehyde was suddenly diluted, the rate of efflux of acetaldehyde was slow relative to the rate of ethanol efflux, suggesting that acetaldehyde, unlike ethanol, may accumulate intracellularly. Intracellular acetaldehyde concentrations were measured during high cell density fermentations, using direct injection gas chromatography to avoid the need to concentrate or disrupt the cells. Intracellular acetaldehyde concentrations substantially exceeded the extracellular concentrations throughout fermentation and were generally much higher than the acetaldehyde concentrations normally recorded in the culture broth in ethanol fermentations. The technique used was sensitive to the time taken to cool and freeze the samples. Measured intracellular acetaldehyde concentrations fell rapidly as the time taken to freeze the suspensions was extended beyond 2 s. The results add weight to recent claims that acetaldehyde toxicity is responsible for some of the effects previously ascribed to ethanol in alcohol fermentations, especially Zymomonas fermentations. Further work is required to confirm the importance of acetaldehyde toxicity under other culture conditions. © 1993 John Wiley & Sons, Inc.