Papers by Claudine Charpentier
Journal of Industrial …, 2002
As important as the blend of base wines before bottling, one of the most important steps in the c... more As important as the blend of base wines before bottling, one of the most important steps in the champagne-making process is the long ageing on lees. Two yeast strains of Saccharomyces cerevisiae MC001 and MC002, used in champagne wine production, were allowed to autolyse. After 8 days of autolysis, active dry yeasts adapted to wine released 1.7-to 1.8-fold more nitrogen compounds than nonadapted active dry yeast. The nitrogen content (total, proteins, peptides and amino) present in autolysates was measured for yeasts adapted to wine. The composition of free amino acids and amino acids constituting peptides showed no difference between the two strains of yeast used. Studies of intracellular proteolytic activity and release of peptides showed no correlation between these two phenomena. These results indicate that yeasts adapted to wine give results similar to those that occur in wine during ageing.
FEMS Microbiology Letters, 2001
Pichia membranifaciens strain FY-101, isolated from grape skins, was found to be antagonistic to ... more Pichia membranifaciens strain FY-101, isolated from grape skins, was found to be antagonistic to Botrytis cinerea, the causal organism of the grey mould disease of the grapevine. When grown together on solid as well as liquid media, the yeast brings about the inhibition of this parasitic fungus, coagulation and leakage of its cytoplasm, and suppression of its ability to produce the characteristic grey mould symptoms on the grapevine plantlets. In vitro experiments confirm that this yeast can be used as a biological control organism against B. cinerea. An account of the molecular characterisation of P. membranifaciens (complete sequence of the ITS region of its ribosomal DNA, GenBank accession No. AF 270935), as well as the interaction between B. cinerea and the yeast, are given here. ß
Wine biological aging is a wine making process used to produce specific beverages in several coun... more Wine biological aging is a wine making process used to produce specific beverages in several countries in Europe, including Spain, Italy, France, and Hungary. This process involves the formation of a velum at the surface of the wine. Here, we present the first large scale comparison of all European flor strains involved in this process. We inferred the population structure of these European flor strains from their microsatellite genotype diversity and analyzed their ploidy. We show that almost all of these flor strains belong to the same cluster and are diploid, except for a few Spanish strains. Comparison of the array hybridization profile of six flor strains originating from these four countries, with that of three wine strains did not reveal any large segmental amplification. Nonetheless, some genes, including YKL221W/MCH2 and YKL222C, were amplified in the genome of four out of six flor strains. Finally, we correlated ICR1 ncRNA and FLO11 polymorphisms with flor yeast population structure, and associate the presence of wild type ICR1 and a long Flo11p with thin velum formation in a cluster of Jura strains. These results provide new insight into the diversity of flor yeast and show that combinations of different adaptive changes can lead to an increase of hydrophobicity and affect velum formation.
Applied Microbiology and Biotechnology, 1986
Flocculation of Kluyveromyces bulgaricus and Saccharomyces uvarum occurred when these yeasts were... more Flocculation of Kluyveromyces bulgaricus and Saccharomyces uvarum occurred when these yeasts were grown in a peptone glucose medium enriched with calcium ions. K. bulgaricus and S. uvarum flocculated at the beginning and at the end, respectively, of the exponential growth phase. After growth, both yeasts were washed with an EDTA solution, flocculated again in an acetate buffer, and optimum flocculation was obtained at pH 4.5 in the presence of 3.75 mM Ca + +. K. bulgaricus flocculation was irreversibly suppressed by incubation at 80°C for 6 min. S. uvarum needed an incubation at 100°C for 20 rain to be irreversibly deflocculated. For both yeasts, flocculation stability depended on the presence of sugars. Mannose, mannose 6P and oligosaccharides bearing a mannose in a terminal non-reducing position reversed flocculation of S. uvarum, while galactose, galactose 6P and oligosaccharides bearing a galactose in a terminal nonreducing position reversed flocculation of K. bulgaricus. It is suggested that sugars specifically reverse flocculation because cell-to-cell aggregation of these yeasts is a lectin-carbohydrate-linked mechanism; not any sugar is capable of deflocculating any yeast, but the mechanism is specific.
Antonie van Leeuwenhoek, 2009
Fifty-four Saccharomyces cerevisiae strains were isolated from Jura ''Vin Jaune'' velum and chara... more Fifty-four Saccharomyces cerevisiae strains were isolated from Jura ''Vin Jaune'' velum and characterized by conventional physiological and molecular tests including ITS RFLP and sequence analysis, karyotyping and inter delta typing. ITS RFLP and sequence revealed a specific group of related strains different from the specific profile of Sherry flor yeast caused by a 24 bp deletion in the ITS1 region described by Esteve-Zarzoso et al. (Antonie Van Leeuwenhoek 85:151-158, 2004). Interdelta typing, the most discriminative method, revealed a high diversity of Jura flor yeast strains and gathered strains in clusters unequally shared between the northern and southern part of the Jura vineyard. The assessment of phenotypic diversity among the isolated strains was investigated for three wine metabolites (ethanal, acetic acid, and sotolon) from micro scale velum tests. Except at an early stage of ageing, the production of these metabolites was not correlated to the five genetic groups obtained by interdelta typing, but correlated to the cellar where strains had been isolated. The different strains isolated in a cellar produced mostly one type of velum (thin or thick, grey or white); but thin and grey velums, recognized as responsible for high quality wines, were obtained more frequently for one of the five groups of delta genotypes.
PLoS ONE, 2014
Wine biological aging is a wine making process used to produce specific beverages in several coun... more Wine biological aging is a wine making process used to produce specific beverages in several countries in Europe, including Spain, Italy, France, and Hungary. This process involves the formation of a velum at the surface of the wine. Here, we present the first large scale comparison of all European flor strains involved in this process. We inferred the population structure of these European flor strains from their microsatellite genotype diversity and analyzed their ploidy. We show that almost all of these flor strains belong to the same cluster and are diploid, except for a few Spanish strains. Comparison of the array hybridization profile of six flor strains originating from these four countries, with that of three wine strains did not reveal any large segmental amplification. Nonetheless, some genes, including YKL221W/MCH2 and YKL222C, were amplified in the genome of four out of six flor strains. Finally, we correlated ICR1 ncRNA and FLO11 polymorphisms with flor yeast population structure, and associate the presence of wild type ICR1 and a long Flo11p with thin velum formation in a cluster of Jura strains. These results provide new insight into the diversity of flor yeast and show that combinations of different adaptive changes can lead to an increase of hydrophobicity and affect velum formation.
Uploads
Papers by Claudine Charpentier