Surface Properties of Top- and Bottom-Fermenting Yeast

Dengis, Pascale B.; Rouxhet, Paul

doi:10.1002/(sici)1097-0061(199708)13:10<931::aid-yea149>3.0.co;2-t

Cited by 41 publications

(21 citation statements)

References 33 publications

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“…The cell charge of brewing and the constitutively flocculent strains varied during the growth; however, no clear relationship among the CSC and the onset (or loss) of flocculation of the brewing strains was observed. These results are in agreement with other authors, which attribute a minor role of CSC on the onset of flocculation (Smit et al 1992;Dengis et al 1995;Dengis and Rouxhet 1997). Although it is described that ale (top) brewing fermentation strains are less negative charged than lager (bottom) strains Mestdagh et al 1990), no clear difference on the CSC was observed in the three strains used.…”

Section: Discussionsupporting

confidence: 92%

“…It is conceivable that the reduction of global cell charge (non-specific electrostatic repulsion) should facilitate yeast cells approach; in this case, the macromolecules (lectins) present on yeast cell surface can easily overcome the negative barrier and the junction between lectins and carbohydrates (specific cell adhesion mechanism) is easier established. However, no clear relationship between yeast surface charge and the onset of flocculation was found Dengis et al 1995;Dengis and Rouxhet 1997).…”

Section: Introductionmentioning

confidence: 99%

“…Some authors described no significant differences in hydrophobicity between flocculent and non-flocculent cells at stationary and exponential phases of growth, respectively (Dengis et al 1995;Dengis and Rouxhet 1997). In contrast, there are several pieces of evidence that suggest a positive correlation between the increase of CSH and the onset of flocculation in brewing yeasts (Smit et al 1992;Straver et al 1993;Rhymes and Smart 2000;Jin et al 2001;Speers et al 2006).…”

Section: Introductionmentioning

confidence: 99%

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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: Discussionsupporting

confidence: 92%

Section: Introductionmentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

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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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“…For example, many yeast strains used in the brewing and wine industries form either flocs (e.g., bottom-fermenting yeasts used to make lagers) or flors (e.g., top-fermenting yeasts used to make sherry wines). In general, strains that form flors have higher surface hydrophobicity than those that form flocs (12). Unlike these industrial yeasts, most laboratory yeasts form neither flors nor flocs.…”

Section: Background (I) the Multifarious Yeast Communitymentioning

confidence: 99%

Cell Signals, Cell Contacts, and the Organization of Yeast Communities

Honigberg

2011

Eukaryot Cell

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Even relatively simple species have evolved mechanisms to organize individual organisms into communities, such that the fitness of the group is greater than the fitness of isolated individuals. Within the fungal kingdom, the ability of many yeast species to organize into communities is crucial for their growth and survival, and this property has important impacts both on the economy and on human health. Over the last few years, studies of Saccharomyces cerevisiae have revealed several fundamental properties of yeast communities. First, strainto-strain variation in the structures of these groups is attributable in part to variability in the expression and functions of adhesin proteins. Second, the extracellular matrix surrounding these communities can protect them from environmental stress and may also be important in cell signaling. Finally, diffusible signals between cells contribute to community organization so that different regions of a community express different genes and adopt different cell fates. These findings provide an arena in which to view fundamental mechanisms by which contacts and signals between individual organisms allow them to assemble into functional communities.In many species, including our own, individual organisms assemble into communities to increase their overall fitness. Even in unicellular organisms like Saccharomyces cerevisiae, individual cells can organize themselves into a variety of types of multicellular aggregates. These biotic communities likely provide overall benefit to these yeast populations, for example by protecting organisms in the core of the structure from environmental stresses or by specializing functions to subpopulations within the community. Yeast communities also have broad relevance to human health and to industry. For example, biofilms formed by pathogenic yeasts on medical devices, such as catheters, are a major cause of the very high mortality rates of hospital-acquired fungal infections (reviewed in references 11, 43, and 44). Furthermore, surface film communities formed on food by spoilage yeasts may result in losses of billions of dollars annually (reviewed in reference 58). Yet the mechanisms underlying the organization of these communities are still poorly understood.In the first section of this paper, I review types of yeast communities, focusing on the model yeast Saccharomyces cerevisiae, and briefly discuss broader aspects of two processes fundamental to yeast communities: cell-cell signaling and cell adhesion. In the second section, I discuss four aspects of yeast community organization highlighted by recent publications: boundary formation, cell adhesion, the extracellular matrix (ECM), and diffusible cell-cell signals. Much of this recent progress has focused on the cytological structures of these communities and on the identification of several genetic pathways required for this organization. BACKGROUND. (I) THE MULTIFARIOUSYEAST COMMUNITY

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“…In dependency on the environmental conditions, these groups have an influence on the electrochemical charge of the cell wall [24,25]. Additionally the microbes produce extracellular polymeric substances (EPS) that may have an influence on the environmental conditions.…”

Section: Eps Analysismentioning

confidence: 99%

Biocoagulation and its Application Potentials for Mineral Bioprocessing

Kuyumcu

Bielig²,

Vilinska³

et al. 2009

TOMPJ

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Summary:The well-known sorting processes like density separation, separation in magnetic or electric fields and flotation, are not suitable to apply successfully within a particle-size range smaller than 10 m. Due to insufficient selectivity of above mentioned enrichment processes the concentrate recovery at this particle size range is extremely poor, which influences accordingly the techno-economic efficiency of mineral processing negative.Based on a process design idea, investigations confirm that the biocoagulation of microorganisms and solid particles can be used to generate coarser sized coagulates which are more suitable for sorting. Experimental investigations showed that microorganisms like Saccharomyces cerevisiae and Yarrowia lipolytica and sulphide particles like galena and sphalerite below 10 m coagulate effectively. Theoretical thermodynamic and extended DLVO theory calculations are in good agreement with microorganisms adhesion onto metal sulphides but not on silicates and selective biocoagulation of sulphides. Furthermore it has been demonstrated that flotation is suitable for the separation of the selectively formed biocoagulates.

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Surface Properties of Top- and Bottom-Fermenting Yeast

Cited by 41 publications

References 33 publications

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

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

Cell Signals, Cell Contacts, and the Organization of Yeast Communities

Biocoagulation and its Application Potentials for Mineral Bioprocessing

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