Pb2+Inhibits Competitively Flocculation of Saccharomyces cerevisiae

Gouveia, Cláudia; Soares, Eduardo V.

doi:10.1002/j.2050-0416.2004.tb00193.x

Cited by 13 publications

(8 citation statements)

References 20 publications

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“…The protein Avidin (labelled with fluorescein isothiocyanate) contains a mannose side chain, which functions as a binding site to flocculins. Active flocculation lectins are able to bind Avidin-FITC molecules, which results in the labelling of the yeast cells (Patelakis et al 1998;Gouveia and Soares 2004;Speers et al 2006). Brewing ale flocculent cells, in stationary phase of growth, and in the presence of Ca 2+ , were able to fix Avidin-FITC probe, as it can be seen in Fig.…”

Section: Resultsmentioning

confidence: 88%

Flocculation in ale brewing strains of Saccharomyces cerevisiae: re-evaluation of the role of cell surface charge and hydrophobicity

Holle

Machado

Soares

2011

Appl Microbiol Biotechnol

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Flocculation is an eco-friendly process of cell separation, which has been traditionally exploited by the brewing industry. Cell surface charge (CSC), cell surface hydrophobicity (CSH) and the presence of active flocculins, during the growth of two (NCYC 1195 and NCYC 1214) ale brewing flocculent strains, belonging to the NewFlo phenotype, were examined. Ale strains, in exponential phase of growth, were not flocculent and did not present active flocculent lectins on the cell surface; in contrast, the same strains, in stationary phase of growth, were highly flocculent (>98%) and presented a hydrophobicity of approximately three to seven times higher than in exponential phase. No relationship between growth phase, flocculation and CSC was observed. For comparative purposes, a constitutively flocculent strain (S646-1B) and its isogenic non-flocculent strain (S646-8D) were also used. The treatment of ale brewing and S646-1B strains with pronase E originated a loss of flocculation and a strong reduction of CSH; S646-1B pronase E-treated cells displayed a similar CSH as the non-treated S646-8D cells. The treatment of the S646-8D strain with protease did not reduce CSH. In conclusion, the increase of CSH observed at the onset of flocculation of ale strains is a consequence of the presence of flocculins on the yeast cell surface and not the cause of yeast flocculation. CSH and CSC play a minor role in the auto-aggregation of the ale strains since the degree of flocculation is defined, primarily, by the presence of active flocculins on the yeast cell wall.

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Section: Resultsmentioning

confidence: 88%

Flocculation in ale brewing strains of Saccharomyces cerevisiae: re-evaluation of the role of cell surface charge and hydrophobicity

Holle

Machado

Soares

2011

Appl Microbiol Biotechnol

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“…On the contrary, cations like Ba 2+ , Sr 2+ and Pb 2+ competitively inhibit yeast flocculation because of the similarity of their ionic ratio to Ca 2+ (Nishihara et al. 1982; Gouveia and Soares 2004). Possibly, these cations compete for the same ‘calcium site’ of flocculation lectins, but are not able to induce the correct conformation of the lectins.…”

Section: Factors Affecting Flocculationmentioning

confidence: 99%

Flocculation in Saccharomyces cerevisiae: a review

Soares

2010

Journal of Applied Microbiology

250

201

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Summary The present work reviews and critically discusses the aspects that influence yeast flocculation, namely the chemical characteristics of the medium (pH and the presence of bivalent ions), fermentation conditions (oxygen, sugars, growth temperature and ethanol concentration) and the expression of specific genes such as FLO1, Lg‐FLO1, FLO5, FLO8, FLO9 and FLO10. In addition, the metabolic control of loss and onset of flocculation is reviewed and updated. Flocculation has been traditionally used in brewing production as an easy and off‐cost cell‐broth separation process. The advantages of using flocculent yeast strains in the production of other alcoholic beverages (wine, cachaça and sparkling wine), in the production of renewal fuels (bio‐ethanol), in modern biotechnology (production of heterologous proteins) and in environmental applications (bioremediation of heavy metals) are highlighted. Finally, the possibility of aggregation of yeast cells in flocs, as an example of social behaviour (a communitarian strategy for long‐time survival or a means of protection against negative environmental conditions), is discussed.

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“…The promotion of fl occulation by other ions, such as Rb ϩ , Cs ϩ , Fe 2ϩ ,Co 2ϩ , Al 3ϩ and particularly Mg 2ϩ and Mn 2ϩ was also reported ( Miki et al , 1982a ;Nishihara et al , 1982 ;Sousa et al , 1992 ). Ba 2ϩ , Sr 2ϩ , Pb 2ϩ and with less intensity Na ϩ inhibit competitively yeast fl occulation, probably due to the similarity of their ionic ratio to Ca 2ϩ ( Nishihara et al , 1982 ;Gouveia and Soares, 2004 ); most likely, these cations compete for the same " calcium binding site " of fl occulation lectins, being not able to activate the lectin-like component of yeast fl occulation.…”

Section: Physiology Of Yeast Flocculation Ph and Presence Of Ionsmentioning

confidence: 71%

“…This theory is unsatisfactory to explain the fl occulation inhibition by the action of bivalent ions like Sr 2ϩ , Ba 2ϩ or Pb 2ϩ ( Nishihara et al , 1982 ;Gouveia and Soares, 2004 ), as well as by sugars ( Taylor and Orton, 1978 ) or concanavalin A (Con A) ( Miki et al , 1982a ).…”

Section: Flocculation Theoriesmentioning

confidence: 99%