Substrate-accelerated death ofSaccharomyces cerevisiae CBS 8066 under maltose stress
| Autor: | W. Alexander Scheffers, Arthur Kuiper, Cornelis Verduyn, Johannes P. van Dijken, E Postma |
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| Rok vydání: | 1990 |
| Předmět: |
Saccharomyces cerevisiae
Bioengineering Ethanol fermentation Biology Applied Microbiology and Biotechnology Biochemistry Maltose-Binding Proteins chemistry.chemical_compound Proton transport Genetics Maltose Maltose transport Glucose transporter alpha-Glucosidases Hydrogen-Ion Concentration biology.organism_classification Yeast Culture Media Glucose chemistry Crabtree effect Carrier Proteins Biotechnology |
| Zdroj: | Yeast. 6:149-158 |
| ISSN: | 1097-0061 0749-503X |
| Popis: | When Saccharomyces cerevisiae CBS 8066 was grown under maltose limitation, two enzymes specific for maltose utilization were present: a maltose carrier, and the maltose-hydrolysing α-glucosidase. The role of these two enzymes in the physiology of S. cerevisiae was investigated in a comparative study in which Candida utilis CBS 621 was used as a reference organism. Maltose pulses to a maltose-limited chemostat culture of S. cerevisiae resulted in ‘substrate-accelerated death’. This was evident from: (1) enhanced protein release from cells: (2) excretion of glucose into the medium; (3) decreased viability. These effects were specific with respect to both substrate and organism: pulses of glucose to maltose-limited cultures of S. cerevisiae did not result in cell death, neither did maltose pulses to maltose-limited cultures of C. utilis. The maltose-accelerated death of S. cerevisiae is most likely explained in terms of an uncontrolled uptake of maltose into the cell, resulting in an osmotic burst. Our results also provide evidence that the aerobic alcoholic fermentation that occurs after pulsing sugars to sugar-limited cultures of S. cerevisiae (short-term Crabtree effect) cannot solely be explained in terms of the mechanism of sugar transport. Both glucose and maltose pulses to maltose-limited cultures triggered aerobic alcohol formation. However, glucose transport by S. cerevisiae occurs via facilitated diffusion, whereas maltose entry into this yeast is mediated by a maltose/proton symport system. |
| Databáze: | OpenAIRE |
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