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Yeast flocculation: Flocculation onset and receptor availability
Author(s) -
Stratford Malcolm
Publication year - 1993
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.320090111
Subject(s) - flocculation , yeast , biology , saccharomyces cerevisiae , receptor , brewing , concanavalin a , lectin , mannan , biochemistry , microbiology and biotechnology , fermentation , polysaccharide , chemistry , organic chemistry , in vitro
Flocculent strains of brewing yeast grow and ferment as single cells and flocculate in the stationary phase of growth. The switch from single‐celled yeast growth to multi‐celled aggregation, flocculation onset, is of critical importance to the brewing industry. Yeast flocculation involves adhesion of surface‐lectins on flocculent cells to carbohydrate receptors on neighbouring cell‐walls. The presence of carbohydrate receptors, outer‐chain mannan side‐branches, was monitored throughout growth of flocculent and non‐flocculent strains of Saccharomyces cerevisiae , with particular attention to the growth phases where flocculation is normally developed. Receptors were probed by coflocculation with flocculent strains and by aggregation with concanavalin A, a lectin shown to use the same receptors as flocculation. While considerable variation was found in coflocculation and concanavalin A aggregation between strains, little or no change in receptor availability was found throughout the growth of all yeast strains. Yeast cells could easily be coflocculated at any growth stage. It was concluded that receptor availability is not involved in the process of flocculation onset.