Effect of different starvation conditions on the flocculation of Saccharomyces cerevisiae.
OBJECTIVE
To study the effect of different starvation conditions on the flocculation of an ale brewing yeast of Saccharomyces cerevisiae NCYC 1195.


RESULTS
Flocculation was assessed by a micro-flocculation technique (Soares and Mota 1997). Carbon-starved cells of a NewFlo phenotype strain did not lose flocculation during a 48 h period. Cells incubated only in the presence of fermentable carbon sources (glucose, galactose and maltose at 2%, w/v), showed a progressive flocculation loss. The incubation of cells in 4% (v/v) ethanol did not induce a flocculation loss. The simultaneous incubation of cells in the presence of 2% (w/v) glucose and 15 microg ml(-1) cycloheximide hindered flocculation loss. The presence of 0.1 mmol l(-1) PMSF or 10 mmol l-1 EDTA prevented partially or completely, respectively, the loss of flocculation in the presence of glucose.


CONCLUSIONS
Fermentable sugars induced a flocculation loss, which seems to require de novo protein synthesis and the involvement of different proteases.


CONCLUSIONS
The findings reported here contribute to the elucidation of the role of nutrients on the physiological control of yeast flocculation.
Soares
E V
EV
CIEA - Departamento de Engenharia Química, Instituto Superior de Engenharia do Instituto Politécnico do Porto, Rua Dr António Bernardino de Almeida, Porto, Portugal. evs@isep.ipp.pt
Vroman
A
A
D002244:Carbon / Q000502:physiology; D003470:Culture Media; D000431:Ethanol / Q000494:pharmacology; D005285:Fermentation / Q000502:physiology; D005427:Flocculation; D005690:Galactose / Q000494:pharmacology; D005947:Glucose / Q000494:pharmacology; D007218:Industrial Microbiology; D008320:Maltose / Q000494:pharmacology; D018977:Micronutrients / Q000494:pharmacology; D012441:Saccharomyces cerevisiae / Q000187:drug effects / Q000254:growth & development / Q000502:physiology*
D003470:Culture Media; D018977:Micronutrients; D000431:Ethanol; D008320:Maltose; D002244:Carbon; D005947:Glucose; D005690:Galactose