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Substrate‐accelerated death of Saccharomyces cerevisiae CBS 8066 under maltose stress
Author(s) -
Postma Erik,
Verduyn Cornelis,
Kuiper Arthur,
Scheffers W. Alexander,
Van Dijken Johannes P.
Publication year - 1990
Publication title -
yeast
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.923
H-Index - 102
eISSN - 1097-0061
pISSN - 0749-503X
DOI - 10.1002/yea.320060209
Subject(s) - biology , saccharomyces cerevisiae , maltose , substrate (aquarium) , yeast , biochemistry , enzyme , ecology
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.