Direct uptake of sucrose by Saccharomyces cerevisiae in batch and continuous culture.

Orlowski, Joanna H.; Barford, J. P.

doi:10.2323/jgam.37.215

Cited by 24 publications

(20 citation statements)

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“…This could mean that there is a sucrose transport system that is induced when the cells are adapted on sucrose for a long time (up to 14 days). This is in agreement with our earlier reports on sucrose metabolism in S. cerevisiae (3,14,17). It has been reported that under glucose repression, the secretion of internal invertase increases while the external invertase remains low and practically constant (12).…”

Section: And Discussionsupporting

confidence: 83%

“…The major overall metabolic parameters of growth are presented in Table 1. When the cells are growing on sucrose alone, the specific growth and sugar uptake rates increased from 0.38 to 0.55 h-' and the specific sugar uptake increased from 14 to 19 mmol g-biomass-' h-' when the adaptation period was prolonged from 2 to 14 days (17). This is also true for the uptake of radiolabelled sucrose when the cells are adapted on sucrose for a long time (14).…”

Section: And Discussionsupporting

confidence: 51%

“…The absence of fructose in the medium could be as a result of either the low sucrose hydrolysis rate (limited by low invertase levels) which caused the fructose resulting from the hydrolysis to be transported into the cell immediately or the cells had the ability to transport sucrose molecules directly without first hydrolysing them. The first alternative seems unlikely since the specific sugar uptake rate for the adapted cells growing on sucrose and glucose mixtures are almost as high as when the cells are growing on sucrose alone (Table 1); it is also higher than that of cells growing on glucose and fructose mixture (17). The biomass yields ranged from 0.13 to 0.16 g-biomass g-sugar-' which correspond to those earlier reported in chemostat cultures at high dilution rates (2,18) and in batch cultures at high sugar concentrations (6,16).…”

Section: And Discussionmentioning

confidence: 99%

“…The strain of baker's yeast used in this work was Saccharomyces cerevisiae 248 UNSW 703100 (3,14,17). This yeast was maintained on malt agar slopes and stored at 4°C.…”

Section: Methodsmentioning

confidence: 99%

“…Most Saccharomyces cerevisiae strains have two forms of invertase: an external large invertase, which is a glycoprotein, and an internal small invertase (9,15). Some strains of S. cerevisiae have been reported to transport sucrose directly into the cell (14,17,20). …”

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confidence: 99%

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Mechanism of surcrose utilisation by Saccharomyces cerevisiae.

Mwesigye¹,

Barford²

1996

J. Gen. Appl. Microbiol.

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Saccharomyces cerevisiae was grown on different concentrations of sucrose and glucose mixtures after adapting on sucrose. The yeast cells were found to have two different mechanisms by which sucrose was utilised: hydrolysis outside the cell membrane and direct transport into the cells. The mechanism by which sucrose was utilised depended on the initial concentration of glucose in the mixture and the adaptation state of the cells. In both cases, glucose was utilised first and invertase secretion was repressed when the glucose concentration was higher than 2 g l-'. The major important finding in our results is that, for fully sucrose-adapted cells, even in the presence of a repressive glucose concentration, the yeast cells were able to utilise sucrose, and most importantly, without first being hydrolysed to its constituent monosaccharides. Previously, it has been thought that direct transport of sucrose contributes only a small part of the process of utilisation of sucrose, but as our results indicate it can be the major mechanism of sucrose utilisation in S. cerevisiae if the cells are adapted on sucrose for long periods, glucose concentrations in the medium are high and/or invertase activities are limiting.The initial steps in the utilisation of sugars by yeast is either the passage of intact sugar molecules across the cell membrane or the hydrolysis outside the cell followed by entry of all or some of the hydrolytic products into the cell. Sugar transport into microbial cells across the plasmalemma can take place by active transport, facilitated diffusion and group translocation (19).Sucrose utilisation involves its hydrolysis outside the yeast cell by extracellular enzyme invertase ($-D-fructosidase) into glucose and fructose which are then transported into the cells and metabolised. Most Saccharomyces cerevisiae strains have two forms of invertase: an external large invertase, which is a glycoprotein, and an internal small invertase (9,15). Some strains of S. cerevisiae have been reported to transport sucrose directly into the cell (14,17,20).

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Section: And Discussionsupporting

confidence: 83%

Section: And Discussionsupporting

confidence: 51%

Section: And Discussionmentioning

confidence: 99%

“…The strain of baker's yeast used in this work was Saccharomyces cerevisiae 248 UNSW 703100 (3,14,17). This yeast was maintained on malt agar slopes and stored at 4°C.…”

Section: Methodsmentioning

confidence: 99%

mentioning

confidence: 99%

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