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Maurizio Ciani - One of the best experts on this subject based on the ideXlab platform.
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evaluation of damage induced by kwkt and pikt zymocins against brettanomyces Dekkera spoilage yeast as compared to sulphur dioxide
Journal of Applied Microbiology, 2016Co-Authors: Lucia Oro, Maurizio Ciani, Davide Bizzaro, Francesca ComitiniAbstract:AIMS Over the last few decades, the use of zymocins as biological tools to counteract contamination by spoilage yeast in beverages and food has been widely studied. This study examined the damage induced by the Kwkt and Pikt, two zymocins produced by Kluyeromyces wickerhamii and Wickerhanomyces anomalus, respectively, with antimicrobial activity against Brettanomyces/Dekkera wine-spoilage yeast. METHODS AND RESULTS The physiological and biochemical characterization of both of these proteins revealed that only Pikt showed a strict relationship between β-glucosidase activity and killer activity. The minimum inhibitory concentrations and minimum fungicidal concentrations of Kwkt and Pikt showed inhibitory activities against Brettanomyces/Dekkera yeast. Cytofluorimetric evaluation of cell death was based on both cell membrane permeability and cell metabolism, using fluorescence techniques under increasing zymocin levels over different incubation times. The antimicrobial actions of Kwkt and Pikt were also compared with the mode of action of sulphur dioxide. In this last case, the induction of the viable but noncultivable (VBNC) state was confirmed, with the consequent recovery of Brettanomyces yeast after medium replacement. In contrast, Kwkt and Pikt caused irreversible death of these yeast, without recovery of sensitive cells. CONCLUSIONS Kwkt and Pikt could be proposed as fungistatic or fungicide biocontrol agents in winemaking to control the colonization and development of Brettanomyces/Dekkera yeasts. SIGNIFICANCE AND IMPACT OF THE STUDY These data support the potential use of zymocins to reduce wine contamination as an alternative to sulphur dioxide that act on sensitive cells. Differently from sulphur dioxide, that could induce a reversible VBNC state, Kwkt and Pikt determine the irreversible damage on sensitive yeasts, ensuring the complete control of spoilage Brettanomyces yeast.
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Evaluation of damage induced by Kwkt and Pikt zymocins against Brettanomyces/Dekkera spoilage yeast, as compared to sulphur dioxide
Journal of applied microbiology, 2016Co-Authors: Lucia Oro, Maurizio Ciani, Davide Bizzaro, Francesca ComitiniAbstract:AIMS Over the last few decades, the use of zymocins as biological tools to counteract contamination by spoilage yeast in beverages and food has been widely studied. This study examined the damage induced by the Kwkt and Pikt, two zymocins produced by Kluyeromyces wickerhamii and Wickerhanomyces anomalus, respectively, with antimicrobial activity against Brettanomyces/Dekkera wine-spoilage yeast. METHODS AND RESULTS The physiological and biochemical characterization of both of these proteins revealed that only Pikt showed a strict relationship between β-glucosidase activity and killer activity. The minimum inhibitory concentrations and minimum fungicidal concentrations of Kwkt and Pikt showed inhibitory activities against Brettanomyces/Dekkera yeast. Cytofluorimetric evaluation of cell death was based on both cell membrane permeability and cell metabolism, using fluorescence techniques under increasing zymocin levels over different incubation times. The antimicrobial actions of Kwkt and Pikt were also compared with the mode of action of sulphur dioxide. In this last case, the induction of the viable but noncultivable (VBNC) state was confirmed, with the consequent recovery of Brettanomyces yeast after medium replacement. In contrast, Kwkt and Pikt caused irreversible death of these yeast, without recovery of sensitive cells. CONCLUSIONS Kwkt and Pikt could be proposed as fungistatic or fungicide biocontrol agents in winemaking to control the colonization and development of Brettanomyces/Dekkera yeasts. SIGNIFICANCE AND IMPACT OF THE STUDY These data support the potential use of zymocins to reduce wine contamination as an alternative to sulphur dioxide that act on sensitive cells. Differently from sulphur dioxide, that could induce a reversible VBNC state, Kwkt and Pikt determine the irreversible damage on sensitive yeasts, ensuring the complete control of spoilage Brettanomyces yeast.
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kluyveromyces wickerhamii killer toxin purification and activity towards brettanomyces Dekkera yeasts in grape must
Fems Microbiology Letters, 2011Co-Authors: Francesca Comitini, Maurizio CianiAbstract:Brettanomyces/Dekkera yeasts have been identified as part of the grape yeast flora. They are well known for colonizing the cellar environmental and spoiling wines, causing haze, turbidity and strong off-flavours in wines and enhancing the volatile acidity. As the general practices applied to combat Brettanomyces/Dekkera yeasts are not particularly appropriate during wine ageing and storage, a biological alternative to curtailing their growth would be welcomed in winemaking. In this study, we investigated the Kluyveromyces wickerhamii killer toxin (Kwkt) that is active against Brettanomyces/Dekkera spoilage yeasts. Purification procedures allowed the identification of Kwkt as a protein with an apparent molecular mass of 72 kDa and without any glycosyl residue. Interestingly, purified Kwkt has fungicidal effects at low concentrations under the physicochemical conditions of winemaking. The addition of 40 and 80 mg L−1 purified Kwkt showed efficient antispoilage effects, controlling both growth and metabolic activity of sensitive spoilage yeasts. At these two killer toxin concentrations, compounds known to contribute to the ‘Brett’ character of wines, such as ethyl phenols, were not produced. Thus, purified Kwkt appears to be a suitable biological strategy to control Brettanomyces/Dekkera yeasts during fermentation, wine ageing and storage.
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Kluyveromyces wickerhamii killer toxin: purification and activity towards Brettanomyces/Dekkera yeasts in grape must
FEMS microbiology letters, 2011Co-Authors: Francesca Comitini, Maurizio CianiAbstract:Brettanomyces/Dekkera yeasts have been identified as part of the grape yeast flora. They are well known for colonizing the cellar environmental and spoiling wines, causing haze, turbidity and strong off-flavours in wines and enhancing the volatile acidity. As the general practices applied to combat Brettanomyces/Dekkera yeasts are not particularly appropriate during wine ageing and storage, a biological alternative to curtailing their growth would be welcomed in winemaking. In this study, we investigated the Kluyveromyces wickerhamii killer toxin (Kwkt) that is active against Brettanomyces/Dekkera spoilage yeasts. Purification procedures allowed the identification of Kwkt as a protein with an apparent molecular mass of 72 kDa and without any glycosyl residue. Interestingly, purified Kwkt has fungicidal effects at low concentrations under the physicochemical conditions of winemaking. The addition of 40 and 80 mg L−1 purified Kwkt showed efficient antispoilage effects, controlling both growth and metabolic activity of sensitive spoilage yeasts. At these two killer toxin concentrations, compounds known to contribute to the ‘Brett’ character of wines, such as ethyl phenols, were not produced. Thus, purified Kwkt appears to be a suitable biological strategy to control Brettanomyces/Dekkera yeasts during fermentation, wine ageing and storage.
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pichia anomala and kluyveromyces wickerhamii killer toxins as new tools against Dekkera brettanomyces spoilage yeasts
Fems Microbiology Letters, 2004Co-Authors: Francesca Comitini, Laura Pepe, Ilaria Maria Mannazzu, Maurizio CianiAbstract:Two yeast killer toxins active on spoilage yeasts belonging to the genus Dekkera/Brettanomyces are here described for the first time. The two toxins produced by Pichia anomala (DBVPG 3003) and Kluyveromyces wickerhamii (DBVPG 6077), and named Pikt and Kwkt, respectively, differ for molecular weight and biochemical properties. Interestingly, the fungicidal effect exerted by Pikt and Kwkt against Dekkera bruxellensis is stable for at least 10 days in wine. Thus, a potential application for the two toxins as antimicrobial agents active on Dekkera/Brettanomyces during wine ageing and storage can be hypothesised.
Francesca Comitini - One of the best experts on this subject based on the ideXlab platform.
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evaluation of damage induced by kwkt and pikt zymocins against brettanomyces Dekkera spoilage yeast as compared to sulphur dioxide
Journal of Applied Microbiology, 2016Co-Authors: Lucia Oro, Maurizio Ciani, Davide Bizzaro, Francesca ComitiniAbstract:AIMS Over the last few decades, the use of zymocins as biological tools to counteract contamination by spoilage yeast in beverages and food has been widely studied. This study examined the damage induced by the Kwkt and Pikt, two zymocins produced by Kluyeromyces wickerhamii and Wickerhanomyces anomalus, respectively, with antimicrobial activity against Brettanomyces/Dekkera wine-spoilage yeast. METHODS AND RESULTS The physiological and biochemical characterization of both of these proteins revealed that only Pikt showed a strict relationship between β-glucosidase activity and killer activity. The minimum inhibitory concentrations and minimum fungicidal concentrations of Kwkt and Pikt showed inhibitory activities against Brettanomyces/Dekkera yeast. Cytofluorimetric evaluation of cell death was based on both cell membrane permeability and cell metabolism, using fluorescence techniques under increasing zymocin levels over different incubation times. The antimicrobial actions of Kwkt and Pikt were also compared with the mode of action of sulphur dioxide. In this last case, the induction of the viable but noncultivable (VBNC) state was confirmed, with the consequent recovery of Brettanomyces yeast after medium replacement. In contrast, Kwkt and Pikt caused irreversible death of these yeast, without recovery of sensitive cells. CONCLUSIONS Kwkt and Pikt could be proposed as fungistatic or fungicide biocontrol agents in winemaking to control the colonization and development of Brettanomyces/Dekkera yeasts. SIGNIFICANCE AND IMPACT OF THE STUDY These data support the potential use of zymocins to reduce wine contamination as an alternative to sulphur dioxide that act on sensitive cells. Differently from sulphur dioxide, that could induce a reversible VBNC state, Kwkt and Pikt determine the irreversible damage on sensitive yeasts, ensuring the complete control of spoilage Brettanomyces yeast.
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Evaluation of damage induced by Kwkt and Pikt zymocins against Brettanomyces/Dekkera spoilage yeast, as compared to sulphur dioxide
Journal of applied microbiology, 2016Co-Authors: Lucia Oro, Maurizio Ciani, Davide Bizzaro, Francesca ComitiniAbstract:AIMS Over the last few decades, the use of zymocins as biological tools to counteract contamination by spoilage yeast in beverages and food has been widely studied. This study examined the damage induced by the Kwkt and Pikt, two zymocins produced by Kluyeromyces wickerhamii and Wickerhanomyces anomalus, respectively, with antimicrobial activity against Brettanomyces/Dekkera wine-spoilage yeast. METHODS AND RESULTS The physiological and biochemical characterization of both of these proteins revealed that only Pikt showed a strict relationship between β-glucosidase activity and killer activity. The minimum inhibitory concentrations and minimum fungicidal concentrations of Kwkt and Pikt showed inhibitory activities against Brettanomyces/Dekkera yeast. Cytofluorimetric evaluation of cell death was based on both cell membrane permeability and cell metabolism, using fluorescence techniques under increasing zymocin levels over different incubation times. The antimicrobial actions of Kwkt and Pikt were also compared with the mode of action of sulphur dioxide. In this last case, the induction of the viable but noncultivable (VBNC) state was confirmed, with the consequent recovery of Brettanomyces yeast after medium replacement. In contrast, Kwkt and Pikt caused irreversible death of these yeast, without recovery of sensitive cells. CONCLUSIONS Kwkt and Pikt could be proposed as fungistatic or fungicide biocontrol agents in winemaking to control the colonization and development of Brettanomyces/Dekkera yeasts. SIGNIFICANCE AND IMPACT OF THE STUDY These data support the potential use of zymocins to reduce wine contamination as an alternative to sulphur dioxide that act on sensitive cells. Differently from sulphur dioxide, that could induce a reversible VBNC state, Kwkt and Pikt determine the irreversible damage on sensitive yeasts, ensuring the complete control of spoilage Brettanomyces yeast.
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kluyveromyces wickerhamii killer toxin purification and activity towards brettanomyces Dekkera yeasts in grape must
Fems Microbiology Letters, 2011Co-Authors: Francesca Comitini, Maurizio CianiAbstract:Brettanomyces/Dekkera yeasts have been identified as part of the grape yeast flora. They are well known for colonizing the cellar environmental and spoiling wines, causing haze, turbidity and strong off-flavours in wines and enhancing the volatile acidity. As the general practices applied to combat Brettanomyces/Dekkera yeasts are not particularly appropriate during wine ageing and storage, a biological alternative to curtailing their growth would be welcomed in winemaking. In this study, we investigated the Kluyveromyces wickerhamii killer toxin (Kwkt) that is active against Brettanomyces/Dekkera spoilage yeasts. Purification procedures allowed the identification of Kwkt as a protein with an apparent molecular mass of 72 kDa and without any glycosyl residue. Interestingly, purified Kwkt has fungicidal effects at low concentrations under the physicochemical conditions of winemaking. The addition of 40 and 80 mg L−1 purified Kwkt showed efficient antispoilage effects, controlling both growth and metabolic activity of sensitive spoilage yeasts. At these two killer toxin concentrations, compounds known to contribute to the ‘Brett’ character of wines, such as ethyl phenols, were not produced. Thus, purified Kwkt appears to be a suitable biological strategy to control Brettanomyces/Dekkera yeasts during fermentation, wine ageing and storage.
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Kluyveromyces wickerhamii killer toxin: purification and activity towards Brettanomyces/Dekkera yeasts in grape must
FEMS microbiology letters, 2011Co-Authors: Francesca Comitini, Maurizio CianiAbstract:Brettanomyces/Dekkera yeasts have been identified as part of the grape yeast flora. They are well known for colonizing the cellar environmental and spoiling wines, causing haze, turbidity and strong off-flavours in wines and enhancing the volatile acidity. As the general practices applied to combat Brettanomyces/Dekkera yeasts are not particularly appropriate during wine ageing and storage, a biological alternative to curtailing their growth would be welcomed in winemaking. In this study, we investigated the Kluyveromyces wickerhamii killer toxin (Kwkt) that is active against Brettanomyces/Dekkera spoilage yeasts. Purification procedures allowed the identification of Kwkt as a protein with an apparent molecular mass of 72 kDa and without any glycosyl residue. Interestingly, purified Kwkt has fungicidal effects at low concentrations under the physicochemical conditions of winemaking. The addition of 40 and 80 mg L−1 purified Kwkt showed efficient antispoilage effects, controlling both growth and metabolic activity of sensitive spoilage yeasts. At these two killer toxin concentrations, compounds known to contribute to the ‘Brett’ character of wines, such as ethyl phenols, were not produced. Thus, purified Kwkt appears to be a suitable biological strategy to control Brettanomyces/Dekkera yeasts during fermentation, wine ageing and storage.
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pichia anomala and kluyveromyces wickerhamii killer toxins as new tools against Dekkera brettanomyces spoilage yeasts
Fems Microbiology Letters, 2004Co-Authors: Francesca Comitini, Laura Pepe, Ilaria Maria Mannazzu, Maurizio CianiAbstract:Two yeast killer toxins active on spoilage yeasts belonging to the genus Dekkera/Brettanomyces are here described for the first time. The two toxins produced by Pichia anomala (DBVPG 3003) and Kluyveromyces wickerhamii (DBVPG 6077), and named Pikt and Kwkt, respectively, differ for molecular weight and biochemical properties. Interestingly, the fungicidal effect exerted by Pikt and Kwkt against Dekkera bruxellensis is stable for at least 10 days in wine. Thus, a potential application for the two toxins as antimicrobial agents active on Dekkera/Brettanomyces during wine ageing and storage can be hypothesised.
José António Couto - One of the best experts on this subject based on the ideXlab platform.
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Survival and metabolism of hydroxycinnamic acids by Dekkera bruxellensis in monovarietal wines
Food microbiology, 2020Co-Authors: José António Couto, Francisco M. Campos, Adriana Nunes De ,lima, R. MagalhãesAbstract:Abstract Volatile phenols in wines are responsible for unpleasant aromas, which negatively affect the quality of the wine. These compounds are produced from the metabolism of hydroxycinnamic acids, mainly by the yeasts Brettanomyces/Dekkera. Relevant data, potentially useful to support decisions on how to manage the risk of contamination of wines by Brettanomyces/Dekkera, according to the grape varieties used in the vinification, is important to the wine industry. Therefore, the aim of this work was to evaluate the survival and the metabolism of hydroxycinnamic acids by Dekkera bruxellensis in monovarietal wines. Yeast growth and survival were monitored in fifteen wines, five from each of the grape varieties Touriga Nacional, Cabernet Sauvignon and Syrah, inoculated with a strain of D. bruxellensis. Yeast culturable populations of 107 CFU mL−1 were reduced to undetectable numbers in 24 h in all wines. Plate counts of 104–106 CFU mL−1 were, however, detected after 48 h in most of Touriga Nacional and Cabernet Sauvignon wines and later in Syrah. Viability measurement by flow cytometry showed that a significant part of the populations was in a viable but non-culturable state (VBNC). The time required for the recovery of the culturable state was dependent on the wine, being longer on Syrah wines. Besides the production of ethylphenols, the metabolism of hydroxycinnamic acids by VBNC cells led to the accumulation of vinylphenols at relatively high levels, independently of the grape variety. The flow cytometry methodology showed a higher survival capacity of D. bruxellensis in Touriga Nacional wines, which corroborates with the higher amounts of volatile phenols found on this variety.
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The antimicrobial action of chitosan against the wine spoilage yeasts Brettanomyces/Dekkera
Journal of Chitin and Chitosan Science, 2013Co-Authors: Delfim Ferreira, Diana Moreira, Eduardo M. Costa, Sara Silva, Manuela Pintado, José António CoutoAbstract:Yeasts of the genera Dekkera and Brettanomyces are well known to be involved in the production of volatile phenols in wines imparting aroma defects that may affect wine quality. The monitoring and control of these organisms is of major importance for wine producers. This study aimed to evaluate the effect of chitosan, a natural polysaccharide, on the survival of Brettanomyces/Dekkera and on some physicochemical aspects of wine (pH value, colour intensity and hue, anthocyanin content and antioxidant capacity). Minimum inhibitory concentration (MIC) and minimum lethal concentration (MLC) values were determined for 8 strains of Brettanomyces/Dekkera by the broth microdilution technique. The results show that chitosan inhibits the growth of Brettanomyces/Dekkera at concentrations ranging from 0.20 to 0.50 mg/ml, depending on the molecular weight of the chitosan molecules and on the assayed strain. The low molecular weight (LMW) chitosan presented the smaller MIC values. Time-kill assays performed in wine added of LMW chitosan revealed reduction of yeast cell viability over time. Furthermore, chitosan affected some physicochemical characteristics of wine, particularly the hue and colour intensity. Relevant data, potentially useful for the establishment of regimes comprising the use of chitosan for the control of Dekkera/Brettanomyces yeasts in wine, is presented.N/
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thermal inactivation of the wine spoilage yeasts Dekkera brettanomyces
International Journal of Food Microbiology, 2005Co-Authors: José António Couto, Filipe Neves, Francisco M. Campos, Tim HoggAbstract:The heat resistance of three strains of Dekkera/Brettanomyces (Dekkera anomala PYCC 5,153, Dekkera bruxellensis PYCC 4,801 and Dekkera/Brettanomyces 093) was evaluated at different temperatures between 32.5 and 55 degrees C. Thermal inactivation tests were performed in tartrate buffer solution (pH 4.0) and in wines. In the studies employing buffer as the heating menstruum, measurable thermal inactivation began only at temperatures of 50 degrees C. When heating was performed in wine, significant inactivation begins at 35 degrees C. Subsequent thermal inactivation tests were performed in buffer at various levels of pH, ethanol concentration, and various phenolic acids. Results from experiments in buffer with added ethanol suggest that the greater heat sensitivity shown in wines can be largely attributed to ethanol, although potentiation of this effect might be due to the phenolic content, particularly from ferulic acid. In the range of pH values tested (2.5-4.5), this factor had no influence in the heat inactivation kinetics. Relevant data, in the form of D and Z values calculated in the various environments, potentially useful for the establishment of regimes of thermal control of Dekkera/Brettanomyces yeasts in wine and contaminated equipment is presented.
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Thermal inactivation of the wine spoilage yeasts Dekkera/Brettanomyces.
International journal of food microbiology, 2005Co-Authors: José António Couto, Filipe Neves, Francisco M. Campos, Tim HoggAbstract:Abstract The heat resistance of three strains of Dekkera/Brettanomyces ( Dekkera anomala PYCC 5153, Dekkera bruxellensis PYCC 4801 and Dekkera/Brettanomyces 093) was evaluated at different temperatures between 32.5 and 55 °C. Thermal inactivation tests were performed in tartrate buffer solution (pH 4.0) and in wines. In the studies employing buffer as the heating menstruum, measurable thermal inactivation began only at temperatures of 50 °C. When heating was performed in wine, significant inactivation begins at 35 °C. Subsequent thermal inactivation tests were performed in buffer at various levels of pH, ethanol concentration, and various phenolic acids. Results from experiments in buffer with added ethanol suggest that the greater heat sensitivity shown in wines can be largely attributed to ethanol, although potentiation of this effect might be due to the phenolic content, particularly from ferulic acid. In the range of pH values tested (2.5–4.5), this factor had no influence in the heat inactivation kinetics. Relevant data, in the form of D and Z values calculated in the various environments, potentially useful for the establishment of regimes of thermal control of Dekkera/Brettanomyces yeasts in wine and contaminated equipment is presented.
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Thermal inactivation of the wine spoilage yeasts Dekkera/Brettanomyces.
International journal of food microbiology, 2005Co-Authors: José António Couto, Filipe Neves, Francisco M. Campos, Tim HoggAbstract:The heat resistance of three strains of Dekkera/Brettanomyces (Dekkera anomala PYCC 5,153, Dekkera bruxellensis PYCC 4,801 and Dekkera/Brettanomyces 093) was evaluated at different temperatures between 32.5 and 55 degrees C. Thermal inactivation tests were performed in tartrate buffer solution (pH 4.0) and in wines. In the studies employing buffer as the heating menstruum, measurable thermal inactivation began only at temperatures of 50 degrees C. When heating was performed in wine, significant inactivation begins at 35 degrees C. Subsequent thermal inactivation tests were performed in buffer at various levels of pH, ethanol concentration, and various phenolic acids. Results from experiments in buffer with added ethanol suggest that the greater heat sensitivity shown in wines can be largely attributed to ethanol, although potentiation of this effect might be due to the phenolic content, particularly from ferulic acid. In the range of pH values tested (2.5-4.5), this factor had no influence in the heat inactivation kinetics. Relevant data, in the form of D and Z values calculated in the various environments, potentially useful for the establishment of regimes of thermal control of Dekkera/Brettanomyces yeasts in wine and contaminated equipment is presented.
Paul R. Grbin - One of the best experts on this subject based on the ideXlab platform.
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Inhibitory effect of hydroxycinnamic acids on Dekkera spp.
Applied Microbiology and Biotechnology, 2010Co-Authors: Paul R. Grbin, Victoria Harris, Christopher M. Ford, Vladimir JiranekAbstract:Simple phenolic components of wine, hydroxycinnamic acids (HCAs) are known to have antimicrobial properties. This study sought to determine the potential of ferulic acid as an antifungal agent for the control of Dekkera . Growth was inhibited by all HCAs examined in this study, with ferulic acid being the most potent at all concentrations. In the presence of ethanol, the inhibitory effects of ferulic acid were amplified. Scanning electron microscopy images reveal cellular damage upon exposure to ferulic acid. Thus, manipulation of ferulic acid concentrations could be of industrial significance for control of Dekkera and may be the basis for differences in susceptibility of wines to Dekkera spoilage.
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Survey of enzyme activity responsible for phenolic off-flavour production by Dekkera and Brettanomyces yeast
Applied microbiology and biotechnology, 2008Co-Authors: Victoria Harris, Christopher M. Ford, Vladimir Jiranek, Paul R. GrbinAbstract:Volatile phenols are produced by Dekkera yeasts and are of organoleptic importance in alcoholic beverages. The key compound in this respect is 4-ethylphenol, responsible for the medicinal and phenolic aromas in spoiled wines. The microbial synthesis of volatile phenols is thought to occur in two steps, beginning with naturally occurring hydroxycinnamic acids (HCAs). The enzyme phenolic acid decarboxylase (PAD) converts HCAs to vinyl derivatives, which are the substrates of a second enzyme, postulated to be a vinylphenol reductase (VPR), whose activity results in the formation of ethylphenols. Here, both steps of the pathway are investigated, using cell extracts from a number of Dekkera and Brettanomyces species. Dekkera species catabolise ferulic, caffeic and p-coumaric acids and possess inducible enzymes with similar pH and temperature optima. Brettanomyces does not decarboxylate HCAs but does metabolise vinylphenols. Dekkera species form ethylphenols but the VPR enzyme appears to be highly unstable in cell extracts. A partial protein sequence for PAD was determined from Dekkera anomala and may indicate the presence of a novel enzyme in this genus.
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Dekkera and Brettanomyces growth and utilisation of hydroxycinnamic acids in synthetic media
Applied Microbiology and Biotechnology, 2008Co-Authors: Victoria Harris, Paul R. Grbin, Christopher M. Ford, Vladimir JiranekAbstract:Dekkera and Brettanomyces yeast are important spoilage organisms in a number of food and beverage products. Isolates of both genera were cultured in a defined medium and supplemented with hydroxycinnamic acids and vinylphenols to investigate their influence on growth and the formation of ethyl phenol derivatives. The growth rate of Brettanomyces species in the presence of acids was reduced, and no significant conversion to vinyl or ethyl derivatives was observed. The growth rate and substrate utilisation rates of Dekkera anomala and Dekkera bruxellensis yeast differed depending on strain and the acid precursor present. Growth of D. bruxellensis was slowed by the presence of ferulic acid with the addition of 1 mM ferulic acid completely inhibiting growth. This study provides an insight into the spoilage potential of these organisms and possible control strategies involving hydroxycinnamic acids.
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mousy off flavour production in grape juice and wine by Dekkera and brettanomyces yeasts
Australian Journal of Grape and Wine Research, 2000Co-Authors: Paul R. Grbin, Paul A. HenschkeAbstract:The ability of four known species of Dekkera and Brettanomyces yeasts to produce mousy off-flavour in grape juice and wine was investigated for the first time. Using a sensory assessment technique the twelve type strains of Dekkera and Brettanomyces, representing four species, were found to grow and to be capable of producing mousy off-flavour in a grape juice medium; however, differences between strains were apparent. Four strains representing the two species of Dekkera (D. bruxellensis and D. anomala) known to be associated with the spoilage of wine and other fermented beverages were further investigated for mousy off-flavour production in a red and white wine supplemented with nutrients. D. anomala and only one of the three D. bruxellensis strains tested grew in both wines and generally produced a moderate level of off-flavour, whereas the remaining two strains of D. bruxellensis, despite slowly losing viability (10- to 100-fold) over the 52-55 day period, produced detectable off-flavour. This work demonstrates the general ability of Dekkera and Brettanomyces yeasts to produce mousy off-flavour and confirms the importance of these yeasts for off-flavour production in grape juice and wine.
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Mousy off‐flavour production in grape juice and wine by Dekkera and Brettanomyces yeasts
Australian Journal of Grape and Wine Research, 2000Co-Authors: Paul R. Grbin, Paul A. HenschkeAbstract:The ability of four known species of Dekkera and Brettanomyces yeasts to produce mousy off-flavour in grape juice and wine was investigated for the first time. Using a sensory assessment technique the twelve type strains of Dekkera and Brettanomyces, representing four species, were found to grow and to be capable of producing mousy off-flavour in a grape juice medium; however, differences between strains were apparent. Four strains representing the two species of Dekkera (D. bruxellensis and D. anomala) known to be associated with the spoilage of wine and other fermented beverages were further investigated for mousy off-flavour production in a red and white wine supplemented with nutrients. D. anomala and only one of the three D. bruxellensis strains tested grew in both wines and generally produced a moderate level of off-flavour, whereas the remaining two strains of D. bruxellensis, despite slowly losing viability (10- to 100-fold) over the 52-55 day period, produced detectable off-flavour. This work demonstrates the general ability of Dekkera and Brettanomyces yeasts to produce mousy off-flavour and confirms the importance of these yeasts for off-flavour production in grape juice and wine.
Virgilio Loureiro - One of the best experts on this subject based on the ideXlab platform.
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Identification of yeasts isolated from wine-related environments and capable of producing 4-ethylphenol
Food Microbiology, 2003Co-Authors: L Dias, S. Dias, T. Sancho, H. Stender, Amparo Querol, Manuel Malfeito-ferreira, Virgilio LoureiroAbstract:The ability to produce 4-ethylphenol from the substrate p-coumaric acid in synthetic media was evaluated for several yeast species associated with wine production. Molar conversion rates as high as 90% were found by only Dekkera bruxellensis, D. anomala and by some unidentified strains isolated from wine-related environments. Other unidentified strains produced traces of 4-ethylphenol. All unidentified strains showed the same cultural characteristics as D. bruxellensis when grown on DBDM (Dekkera/Brettanomyces differential medium) agar. The determination of long-chain fatty acid compositions and the utilization of peptide nucleic acid (PNA) probes specific for D. bruxellensis showed that the unidentified strains did not belong to this species. Further identification, by restriction pattern generated from PCR-amplification of the 5.8S rRNA gene and the two internal transcribed spacers (ITS), assigned the unidentified strains to Candida cantarelli, C. wickerhamii, Debaryomyces hansenii, Kluyveromyces lactis and Pichia guilliermondii. However, only some strains of P. guilliermondii were capable of converting p-coumaric acid into 4-ethylphenol with efficiencies close to those observed in D. bruxellensis and D. anomala.
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Development and use of a new medium to detect yeasts of the genera Dekkera/Brettanomyces.
Journal of Applied Microbiology, 2001Co-Authors: N. Rodrigues, S. Pereira-da-silva, G Goncalves, Manuel Malfeito-ferreira, Virgilio LoureiroAbstract:AIMS: The objectives of this work were to develop a selective and/or differential medium able to efficiently recover Dekkera/Brettanomyces sp. from wine-related environments and to determine the relationship between these yeasts and the 4-ethylphenol content in a wide range of wines. METHODS AND RESULTS: The selectivity of the developed medium was provided by the addition of ethanol, as single carbon source, and cycloheximide. The inclusion of bromocresol green evidenced acid-producing strains. The inclusion of p-coumaric acid, substrate for the production of 4-ethylphenol, enabled the differentiation by smell of Dekkera/Brettanomyces sp. from all other yeast species growing in the medium. The medium was used either by plating after membrane filtration or by the Most Probable Number (MPN) technique. In 29 white and 88 red randomly collected wines, these yeasts were found only in red wines at levels up to 2500 MPN ml-1, but constituted less than 1% of the total microbial flora. In red wines, 84% showed detectable amounts of 4-ethylphenol up to 4430 microg l-1 while 28% of the white wines showed detectable levels up to 403 microg l-1. CONCLUSION: The use of the medium proposed in this work evidenced the presence of low relative populations of Dekkera/Brettanomyces sp. even in wines contaminated by fast-growing yeasts and moulds. SIGNIFICANCE AND IMPACT OF THE STUDY: Further ecological studies on Dekkera/Brettanomyces sp. should take into account the use of highly specific culture media in order to establish their true occurrence in nature.