Abstract
| Original language | English |
|---|---|
| Pages (from-to) | 211–218 |
| Number of pages | 8 |
| Journal | Journal of the Institute of Brewing |
| Volume | 123 |
| Issue number | 2 |
| Early online date | 29 Mar 2017 |
| DOIs | |
| Publication status | Published - 8 May 2017 |
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Flocculation in industrial strains of Saccharomyces cerevisiae : role of cell wall polysaccharides and lectin-like receptors. / Nayyar, Ashima; Walker, Graeme M.; Wardrop, Forbes; Adya, Ashok K.
In: Journal of the Institute of Brewing, Vol. 123, No. 2, 08.05.2017, p. 211–218.Research output: Contribution to journal › Article
TY - JOUR
T1 - Flocculation in industrial strains of Saccharomyces cerevisiae
T2 - role of cell wall polysaccharides and lectin-like receptors
AU - Nayyar, Ashima
AU - Walker, Graeme M.
AU - Wardrop, Forbes
AU - Adya, Ashok K.
PY - 2017/5/8
Y1 - 2017/5/8
N2 - Yeast flocculation is the reversible aggregation of yeast cells promoted by the interaction between lectin-like protein receptors with mannose side chains on adjacent cell walls. Flocculation is governed by several physiological factors, including the type of nutrient sugar available to yeast. We grew four industrial strains of Saccharomyces cerevisiae, representing applications in the brewing, winemaking and bioethanol sectors, to late stationary phase and quantified the cellular content of mannans, glucans and lectin-like proteins on yeast cell surfaces. Results indicated that brewing and champagne strains showed moderate to high flocculation ability when grown with glucose, fructose, maltose or galactose, whereas winemaking and fuel alcohol strains only showed moderate flocculation when grown on maltose and galactose. All yeast strains studied were weakly flocculent when grown on mannose. With regard to lectin-like receptors, their number played a more important role in governing yeast flocculation than the mannan and glucan contents in yeast cell walls. We conclude that all the industrial strains of S. cerevisiae belonged to New-Flo type on the basis of their flocculation behaviour observed when cultured on different sugars. Quantification of yeast cell wall polysaccharides and receptor sites indicates that mannan and glucan levels remain almost constant, irrespective of the strain under investigation. The main difference in flocculation characteristics in industrial yeast strains appears to be due to variations in concentrations of lectin-like cell surface receptors. Our findings may benefit brewers, winemakers and other yeast-based technologies in design of media to prevent premature flocculation during fermentation.
AB - Yeast flocculation is the reversible aggregation of yeast cells promoted by the interaction between lectin-like protein receptors with mannose side chains on adjacent cell walls. Flocculation is governed by several physiological factors, including the type of nutrient sugar available to yeast. We grew four industrial strains of Saccharomyces cerevisiae, representing applications in the brewing, winemaking and bioethanol sectors, to late stationary phase and quantified the cellular content of mannans, glucans and lectin-like proteins on yeast cell surfaces. Results indicated that brewing and champagne strains showed moderate to high flocculation ability when grown with glucose, fructose, maltose or galactose, whereas winemaking and fuel alcohol strains only showed moderate flocculation when grown on maltose and galactose. All yeast strains studied were weakly flocculent when grown on mannose. With regard to lectin-like receptors, their number played a more important role in governing yeast flocculation than the mannan and glucan contents in yeast cell walls. We conclude that all the industrial strains of S. cerevisiae belonged to New-Flo type on the basis of their flocculation behaviour observed when cultured on different sugars. Quantification of yeast cell wall polysaccharides and receptor sites indicates that mannan and glucan levels remain almost constant, irrespective of the strain under investigation. The main difference in flocculation characteristics in industrial yeast strains appears to be due to variations in concentrations of lectin-like cell surface receptors. Our findings may benefit brewers, winemakers and other yeast-based technologies in design of media to prevent premature flocculation during fermentation.
U2 - 10.1002/jib.421
DO - 10.1002/jib.421
M3 - Article
VL - 123
SP - 211
EP - 218
JO - Journal of the Federated Institutes of Brewing
JF - Journal of the Federated Institutes of Brewing
SN - 0046-9750
IS - 2
ER -