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Papers by Jean-Luc Legras
Molecular ecology, Jan 6, 2015
The domestication of the wine yeast S. cerevisiae is thought to be contemporary with the developm... more The domestication of the wine yeast S. cerevisiae is thought to be contemporary with the development and expansion of viticulture along the Mediterranean basin. Until now, the unavailability of wild lineages prevented the identification of the closest wild relatives of wine yeasts. Here, we enlarge the collection of natural lineages and employ whole genome data of oak-associated wild isolates to study a balanced number of anthropic and natural S. cerevisiae strains. We identified industrial variants and new geographically delimited populations, including a novel Mediterranean oak population. This population is the closest relative of the wine lineage as shown by a weak population structure and further supported by genome-wide population analyses. A coalescent model considering partial isolation with asymmetrical migration, mostly from the wild group into the Wine group, and population growth, was found to be best supported by the data. Importantly, divergence time estimates between ...
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International Journal of Food Microbiology, 2015
In South-West of Burkina Faso, palm wine is produced by spontaneous fermentation of the sap from ... more In South-West of Burkina Faso, palm wine is produced by spontaneous fermentation of the sap from a specific palm tree Borassus akeassii and plays an important role in people's lives. Saccharomyces cerevisiae is the main agent of this alcoholic fermentation but little is known about the diversity of the isolates from palm. In this work, 39 Saccharomyces cerevisiae strains were isolated from palm wine samples collected from 14 sites in Burkina Faso, as well as 7 isolates obtained from sorghum beer (Dolo) from 3 distant sites. Their diversity was analyzed at 12 microsatellite loci, and compared to the genotypes obtained for other African yeast populations isolated from Cocoa hulks from Ghana, sorghum beer from Ivory Coast, palm wine from Djibouti Republic, and to our database of strains from miscellaneous origins (bread, beer, wine, sake, oaks…). The ploidy of these strains has been assessed as well by flow cytometry. Our results show that B. akeassii palm wine contains a specific yeast population of diploid strains, different from Dolo produced in the same area and from other palm wine strains from Ivory Coast, Nigeria, or Djibouti Republic. In contrast, Dolo strains appeared as a group of related and mainly tetraploid strains despite being isolated from different countries.
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Journal of industrial microbiology & biotechnology, 2015
The deliberate inoculation of yeast strains isolated from food matrices such as wine or bread, co... more The deliberate inoculation of yeast strains isolated from food matrices such as wine or bread, could allow the transfer of novel properties to beer. In this work, the feasibility of the use of baker's yeast strains as starters for craft beer production has been evaluated at laboratory and brewery scale. Nine out of 12 Saccharomyces cerevisiae strains isolated from artisanal sourdoughs metabolized 2 % maltose, glucose and trehalose and showed growth rates and cell populations higher than those of the brewer's strain Safbrew-S33. Analysis of allelic variation at 12 microsatellite loci clustered seven baker's strains and Safbrew-S33 in the main group of bread isolates. Chemical analyses of beers produced at a brewery scale showed significant differences among the beers produced with the baker's strain S38 or Safbrew-S33, while no significant differences were observed when S38 or the brewer's strain Safbrew-F2 was used for re-fermentation. The sensory profile of beer...
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Journal of Basic Microbiology, 1989
Abstract Besides its nitrile hydratase and wide spectrum amidase activities, the Brevibacterium s... more Abstract Besides its nitrile hydratase and wide spectrum amidase activities, the Brevibacterium sp. R312 strain also possesses a constitutive β-glucosidase. Its optimum pH is 6. The enzyme was purified by fractionation precipitation with ammonium sulfate followed by chromatographic elutions on Q-Sepharose Fast Flow, Sephadex G-200 and Phenyl Superose. The resulting purification was 1960 folds for a 6% yield. The molecular weight of this enzyme was estimated at 180,000. It contains two identical sub-units. The pI is 5.5. ...
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The enzymatic breakdown of two cyanoglucosides (linamarine and prunassine) was studied in a strai... more The enzymatic breakdown of two cyanoglucosides (linamarine and prunassine) was studied in a strain of Brevibacterium sp. A review is provided of data on the structure, biosynthesis and breakdown of nitrilated compounds in living systems. The biosynthesis of beta-glucosidase is described, as well as the general properties of this enzyme. A study is included of the enzymatic systems responsible for the breakdown of cyanoglucosides in Brevibacterium sp. R312 (beta-glucosidase, nitrile hydratase and amidase), in order to ...
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Revue française d'oenologie, 2011
Résumé/Abstract Saccharomyces cerevisiae est utilisée depuis des millénaires dans la vinification... more Résumé/Abstract Saccharomyces cerevisiae est utilisée depuis des millénaires dans la vinification. Les souches œnologiques présentent des traits particuliers qui résultent d'une double sélection par l'environnement œnologique et par l'homme. Afin de décrypter les mécanismes qui participent à ces processus d'évolution, nous avons séquence le génome de la souche œnologique EC1118. Cette analyse a révélé les particularités de ce génome, en particulier l'existence de plusieurs régions de gènes acquises par transfert horizontal d' ...
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Proceedings of the National Academy of Sciences, 2009
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PLoS ONE, 2011
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Antonie van Leeuwenhoek, Jan 1, 2009
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Molecular …, Jan 1, 2007
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BMC Genomics, 2012
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PLoS ONE, 2014
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Food Microbiology, 2013
Geraniol produced by grape is the main precursor of terpenols which play a key role in the floral... more Geraniol produced by grape is the main precursor of terpenols which play a key role in the floral aroma of white wines. We investigated the fate of geraniol during wine fermentation by Saccharomyces cerevisiae. The volatile compounds produced during fermentation of a medium enriched with geraniol were extracted by Stir-bar sorptive extraction and analysed by GC-MS. We were able to detect and quantify geranyl acetate but also citronellyl- and neryl-acetate. The presence of these compounds partly explains the disparition of geraniol. The amounts of terpenyl esters are strain dependant. We demonstrated both by gene overexpression and gene-deletion the involvement of ATF1 enzyme but not ATF2 in the acetylation of terpenols. The affinity of ATF1 enzyme for several terpenols and for isoamyl alcohol was compared. We also demonstrated that OYE2 is the enzyme involved in geraniol to citronellol reduction. Fermenting strain deleted from OYE2 gene produces far less citronellol than wild type strain. Moreover lab strain over-expressing OYE2 allows 87% geraniol to citronellol reduction in bioconversion experiment compared to about 50% conversion with control strain.
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FEMS Yeast Research, 2007
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Molecular Ecology, 2007
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Molecular ecology, Jan 6, 2015
The domestication of the wine yeast S. cerevisiae is thought to be contemporary with the developm... more The domestication of the wine yeast S. cerevisiae is thought to be contemporary with the development and expansion of viticulture along the Mediterranean basin. Until now, the unavailability of wild lineages prevented the identification of the closest wild relatives of wine yeasts. Here, we enlarge the collection of natural lineages and employ whole genome data of oak-associated wild isolates to study a balanced number of anthropic and natural S. cerevisiae strains. We identified industrial variants and new geographically delimited populations, including a novel Mediterranean oak population. This population is the closest relative of the wine lineage as shown by a weak population structure and further supported by genome-wide population analyses. A coalescent model considering partial isolation with asymmetrical migration, mostly from the wild group into the Wine group, and population growth, was found to be best supported by the data. Importantly, divergence time estimates between ...
Bookmarks Related papers MentionsView impact
International Journal of Food Microbiology, 2015
In South-West of Burkina Faso, palm wine is produced by spontaneous fermentation of the sap from ... more In South-West of Burkina Faso, palm wine is produced by spontaneous fermentation of the sap from a specific palm tree Borassus akeassii and plays an important role in people's lives. Saccharomyces cerevisiae is the main agent of this alcoholic fermentation but little is known about the diversity of the isolates from palm. In this work, 39 Saccharomyces cerevisiae strains were isolated from palm wine samples collected from 14 sites in Burkina Faso, as well as 7 isolates obtained from sorghum beer (Dolo) from 3 distant sites. Their diversity was analyzed at 12 microsatellite loci, and compared to the genotypes obtained for other African yeast populations isolated from Cocoa hulks from Ghana, sorghum beer from Ivory Coast, palm wine from Djibouti Republic, and to our database of strains from miscellaneous origins (bread, beer, wine, sake, oaks…). The ploidy of these strains has been assessed as well by flow cytometry. Our results show that B. akeassii palm wine contains a specific yeast population of diploid strains, different from Dolo produced in the same area and from other palm wine strains from Ivory Coast, Nigeria, or Djibouti Republic. In contrast, Dolo strains appeared as a group of related and mainly tetraploid strains despite being isolated from different countries.
Bookmarks Related papers MentionsView impact
Journal of industrial microbiology & biotechnology, 2015
The deliberate inoculation of yeast strains isolated from food matrices such as wine or bread, co... more The deliberate inoculation of yeast strains isolated from food matrices such as wine or bread, could allow the transfer of novel properties to beer. In this work, the feasibility of the use of baker's yeast strains as starters for craft beer production has been evaluated at laboratory and brewery scale. Nine out of 12 Saccharomyces cerevisiae strains isolated from artisanal sourdoughs metabolized 2 % maltose, glucose and trehalose and showed growth rates and cell populations higher than those of the brewer's strain Safbrew-S33. Analysis of allelic variation at 12 microsatellite loci clustered seven baker's strains and Safbrew-S33 in the main group of bread isolates. Chemical analyses of beers produced at a brewery scale showed significant differences among the beers produced with the baker's strain S38 or Safbrew-S33, while no significant differences were observed when S38 or the brewer's strain Safbrew-F2 was used for re-fermentation. The sensory profile of beer...
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Journal of Basic Microbiology, 1989
Abstract Besides its nitrile hydratase and wide spectrum amidase activities, the Brevibacterium s... more Abstract Besides its nitrile hydratase and wide spectrum amidase activities, the Brevibacterium sp. R312 strain also possesses a constitutive β-glucosidase. Its optimum pH is 6. The enzyme was purified by fractionation precipitation with ammonium sulfate followed by chromatographic elutions on Q-Sepharose Fast Flow, Sephadex G-200 and Phenyl Superose. The resulting purification was 1960 folds for a 6% yield. The molecular weight of this enzyme was estimated at 180,000. It contains two identical sub-units. The pI is 5.5. ...
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The enzymatic breakdown of two cyanoglucosides (linamarine and prunassine) was studied in a strai... more The enzymatic breakdown of two cyanoglucosides (linamarine and prunassine) was studied in a strain of Brevibacterium sp. A review is provided of data on the structure, biosynthesis and breakdown of nitrilated compounds in living systems. The biosynthesis of beta-glucosidase is described, as well as the general properties of this enzyme. A study is included of the enzymatic systems responsible for the breakdown of cyanoglucosides in Brevibacterium sp. R312 (beta-glucosidase, nitrile hydratase and amidase), in order to ...
Bookmarks Related papers MentionsView impact
Revue française d'oenologie, 2011
Résumé/Abstract Saccharomyces cerevisiae est utilisée depuis des millénaires dans la vinification... more Résumé/Abstract Saccharomyces cerevisiae est utilisée depuis des millénaires dans la vinification. Les souches œnologiques présentent des traits particuliers qui résultent d'une double sélection par l'environnement œnologique et par l'homme. Afin de décrypter les mécanismes qui participent à ces processus d'évolution, nous avons séquence le génome de la souche œnologique EC1118. Cette analyse a révélé les particularités de ce génome, en particulier l'existence de plusieurs régions de gènes acquises par transfert horizontal d' ...
Bookmarks Related papers MentionsView impact
Proceedings of the National Academy of Sciences, 2009
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PLoS ONE, 2011
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Antonie van Leeuwenhoek, Jan 1, 2009
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Antonie van Leeuwenhoek, 2009
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Molecular …, Jan 1, 2007
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BMC Genomics, 2012
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PLoS ONE, 2014
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Food Microbiology, 2013
Geraniol produced by grape is the main precursor of terpenols which play a key role in the floral... more Geraniol produced by grape is the main precursor of terpenols which play a key role in the floral aroma of white wines. We investigated the fate of geraniol during wine fermentation by Saccharomyces cerevisiae. The volatile compounds produced during fermentation of a medium enriched with geraniol were extracted by Stir-bar sorptive extraction and analysed by GC-MS. We were able to detect and quantify geranyl acetate but also citronellyl- and neryl-acetate. The presence of these compounds partly explains the disparition of geraniol. The amounts of terpenyl esters are strain dependant. We demonstrated both by gene overexpression and gene-deletion the involvement of ATF1 enzyme but not ATF2 in the acetylation of terpenols. The affinity of ATF1 enzyme for several terpenols and for isoamyl alcohol was compared. We also demonstrated that OYE2 is the enzyme involved in geraniol to citronellol reduction. Fermenting strain deleted from OYE2 gene produces far less citronellol than wild type strain. Moreover lab strain over-expressing OYE2 allows 87% geraniol to citronellol reduction in bioconversion experiment compared to about 50% conversion with control strain.
Bookmarks Related papers MentionsView impact
FEMS Yeast Research, 2007
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Molecular Ecology, 2007
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