Hyperosmotic stress response by strains of bakers' yeasts in high sugar concentration medium

• Published in: Letters in applied microbiology Vol. 31; no. 4; pp. 323 - 327
• Main Authors: Attfield, P.V., Kletsas, S.
• Format: Journal Article
• Language: English
• Published: Oxford, UK Blackwell Science Ltd 01.10.2000; Blackwell Science
• Subjects: Biological and medical sciences; Bread - microbiology; Culture Media; Ethanol - metabolism; Fermentation; Food industries; Food microbiology; Fundamental and applied biological sciences. Psychology; Glycerol - metabolism; Osmotic Pressure; Saccharomyces cerevisiae; Saccharomyces cerevisiae - genetics; Saccharomyces cerevisiae - physiology; Sorbitol - metabolism; Sucrose - metabolism; Glycerol-3-phosphate dehydrogenase; Sucrose; Enzyme; Adaptive response; Glycerol; Gene expression; Stress; Fungi; Osmotic shock; Alcoholic fermentation; Ascomycetes; Baker yeast; Oxidoreductases; Saccharomyces cerevisiae; Thallophyta
• ISSN: 0266-8254; 1472-765X; 1365-2673
• DOI: 10.1046/j.1472-765x.2000.00825.x

Four strains of bakers' yeast were analysed for their hyperosmotic responses when in media that mimic conditions occurring in bread doughs. Two of the strains produced strong fermentative activity in medium with low osmotic stress, but produced considerably less ethanol in high sucrose concentration medium. Two other strains produced more similar fermentation activities across the range of media tested. The strains that were inhibited by high sucrose concentration were unable to produce significant amounts of glycerol under hyperosmotic conditions. By contrast, the yeasts that were not inhibited significantly by high sucrose produced a considerable amount of glycerol. The strains that produced significant glycerol exhibited efficient expression of the glycerol‐3‐phosphate dehydrogenase gene GPD1. These novel data on the molecular responses of industrially relevant strains of bakers' yeasts are prerequisite to designing strategies for improving the performance of industrial yeasts in high sugar concentration media.