Quantitative study of interactions between Saccharomyces cerevisiae and Oenococcus oeni strains

This study examines the interactions that occur between Saccharomyces cerevisiae and Oenococcus oeni strains during the process of winemaking. Various yeast/bacteria pairs were studied by applying a sequential fermentation strategy which simulated the natural winemaking process. First, four yeast strains were tested in the presence of one bacterial strain leading to the inhibition of the bacterial component. The extent of inhibition varied widely from one pair to another and closely depended on the specific yeast strain chosen. Inhibition was correlated to weak bacterial growth rather than a reduction in the bacterial malolactic activity. Three of the four yeast strains were then grown with another bacteria strain. Contrary to the first results, this led to the bacterial stimulation, thus highlighting the importance of the bacteria strain. The biochemical profile of the four yeast fermented media exhibited slight variations in ethanol, SO2 and fatty acids produced as well as assimilable consumed nitrogen. These parameters were not the only factors responsible for the malolactic fermentation inhibition observed with the first bacteria strain. The stimulation of the second has not been reported before in such conditions and remains unexplained

Impact of the co-culture of Saccharomyces cerevisiae–Oenococcus oenion malolactic fermentation and partial characterization of a yeast-derived inhibitory peptidic fraction

The present study was aimed to evaluate the impact of the co-culture on the output of malolactic fermentation and to further investigate the reasons of the antagonism exerted by yeasts towards bacteria during sequential cultures. The Saccharomyces cerevisiae D strain/Oenococcus oeni X strain combination was tested by applying both sequential culture and co-culture strategies. This pair was chosen amongst others because the malolactic fermentation was particularly difficult to realize during the sequential culture. During this traditional procedure, malolactic fermentation started when alcoholic fermentation was achieved. For the co-culture, both fermentations were conducted together by inoculating yeasts and bacteria into a membrane bioreactor at the same time. Results obtained during the sequential culture and compared to a bacterial control medium, showed that the inhibition exerted by S. cerevisiae D strain in term of decrease of the malic acid consumption rate was mainly due to ethanol (75%) and to a peptidic fraction (25%) having an MW between 5 and 10 kDa. 0.4 g l-1 of L-malic acid was consumed in this case while 3.7 g l-1 was consumed when the co-culturewas applied. In addition, therewas no risk of increased volatile acidity during the co-culture. Therefore, the co-culture strategy was considered effective for malolactic fermentation with the yeast/bacteria pair studied

Etude des interactions entre Saccharomyces cerevisiae et Oenococcus oeni : impact sur la réalisation de la fermentation malolactique en cultures séquentielles et mixtes

Pour une bonne maîtrise de la fermentation malolactique (FML) en vinification, il est important d’étudier les différents types d’interactions pouvant exister entre les souches de Saccharomyces cerevisiae et d’Oenococcus oeni, d’identifier les phénomènes et les molécules qui en sont responsables et de définir la façon pertinente de gérer le procédé notamment pour l’inoculation de ces souches. Dans ce travail, nous avons testé plusieurs couples levure-bactérie en appliquant deux stratégies d’inoculation différentes : cultures séquentielles et co-cultures, dans des milieux synthétiques liquides simulant les milieux naturels. Pour les cultures séquentielles, les bactéries lactiques ont été ensemencées à la fin de la fermentation alcoolique alors que pour les cultures mixtes les levures et les bactéries ont été ensemencées simultanément. La réalisation des cultures séquentielles a permis de quantifier l’inhibition ou la stimulation de la FML en fonction des souches sélectionnées dans un couple. Nous avons pu mettre en évidence que l’inhibition de la FML peut être en partie due à des peptides inhibiteurs, piste peu exploitée jusqu'à présent. La caractérisation partielle de deux peptides inhibiteurs synthétisés par deux souches de levure a pu être réalisée. Cet effet inhibiteur se rajoute à celui de certaines molécules inhibitrices déjà connues. Comme alternative aux cultures séquentielles, des cultures mixtes de certains couples ont été réalisées dans un bioréacteur à membrane, outil d’étude dont l’avantage est de séparer physiquement les souches tout en permettant l’homogénéisation du milieu. Pour certains couples, la co-inoculation a pu améliorer le rendement de la FML sans risque de déviation. Les résultats montrent que le choix du couple levure-bactérie est un critère très important dans la réussite de la FML. La réalisation de la co-culture peut être intéressante pour certains couples. En revanche une interaction positive a pu être observée pour d’autres couples dans le cas de cultures séquentielles. Cette stratégie classique peut alors être conservée. ABSTRACT : A good control of malolactic fermentation (MLF) during vinification, implies first to study the different kinds of interactions which may occur between Saccharomyces cerevisiae and Oenococcus oeni strains, second to identify the molecules responsible of these interactions and third to define the pertinent way of running the process notably in what concerns the inoculation of these strains. In this work, we have tested several yeast-bacteria couples by applying two different inoculation strategies: the sequential fermentation and the co-culture, using synthetic liquid media which composition simulates natural ones. While during the sequential fermentations, the lactic acid bacteria were inoculated at the end of the alcoholic fermentation; both yeasts and bacteria were inoculated simultaneously during the co-culture. The sequential fermentations allowed us to quantify the inhibition or stimulation of the MLF depending on the choice of the strains within a couple. We have also showed that the inhibition of MLF can be partially due to inhibitory peptides in addition to some classical inhibitory molecules already described. The partial characterization of two inhibitory peptides synthesized by two yeast strains was carried out in this work. This factor has not been intensively investigated till now. As an alternative for sequential fermentations, co-cultures of certain couples were carried out in a membrane bioreactor which advantage was to keep the strains physically separated while the medium was homogenous. For certain couples, the co-culture strategy improved the MLF output without a risk of deviation. Results show that the choice of a yeast-bacteria couple constitutes an important criterion for the success of MLF. The co-culture can be interesting for certain couples. However, a positive interaction was observed with other couples in the case of sequential fermentation. Therefore, this classical strategy has to be maintained

Impact of inhibitory peptides released by Saccharomyces cerevisiae BDX on the malolactic fermentation performed by Oenococcus oeni Vitilactic F

A previous study has shown that the malolactic fermentation (MLF) was inhibited during sequential fermentations performed with the pair Saccharomyces cerevisiae BDX/Oenococcus oeni Vitilactic F in synthetic grape juices. A yeast peptidic fraction with an apparent MW of 5-10kDa was involved in the inhibition. In the present study, the MLF was also inhibited in Cabernet Sauvignon and Syrah wines. The inhibition due to the peptidic fraction was maintained despite high phenolic contents. Kinetic studies showed that the peptidic fraction was gradually released during the alcoholic fermentation (AF). Its highest anti-MLF effect was reached when isolated from late stages of the AF stationary phase. The peptidic fraction was tested in vitro on cell-free bacterial cytosolic extracts containing the malolactic enzyme in a pH range between 3.5 and 6.7. Results showed that it was able to directly inhibit the malolactic enzyme activity with an increasing inhibitory kinetic correlated to the AF time at which it was collected

Evolution of Polyphenols during Syrah Grapes Maceration: Time versus Temperature Effect

The effect of maceration time and temperature on the phenolic compounds of Syrah grape musts was studied. Pre-fermentation cold (10 °C) and heat maceration (60, 70 and 80 °C) were applied and compared to traditional maceration (control, 25 °C). The macerations were monitored and the kinetic profile of the maceration was studied by taking samples at 0, 2, 4, 8, 24 and 48 h. The results showed that heat treatment had the most significant effect on the extraction of total polyphenol. A significant loss of anthocyanin content was observed when the maceration was extended beyond eight hours at high temperatures, while longer maceration times seemed to favor the extraction of tannins. A principal component analysis showed that independently of the vinification technique, and for the same grape varieties, different winegrowing regions and harvest years affected the phenolic composition of the grape ski

Analysis of the impact of fining agents types, oenological tannins and mannoproteins and their concentrations on the phenolic composition of red wine

This paper aimed to evaluate and analyze the effect of five fining agents, commercial tannins and mannoproteins on the pigment, color and tannins composition of a Cabernet Sauvignon red wine. The wines were analyzed 2 d after treatment and immediately after separation of sedimentation. Color was evaluated by spectrophotometry and polyphenols were analyzed by spectrophotometry and HPLC-DAD. The results showed that all treatments affected the phenolic contents of the wine. The most remarkable effects on phenolic composition were produced by bentonite and Polyvinylpolypyrrolidone (PvPP) + potassium caseinate which significantly decreased anthocyanins and tannins concentrations, respectively. The use of vegetable protein and gelatin has a less impact on the color and phenolic contents of red wines. The antioxidant activity was little affected by treatments except the addition of tannins that increased it. Principal components analysis demonstrates the importance of a low concentration of agents for high total polyphenol levels

Identification of multiple-derived peptides produced by Saccharomyces cerevisiae involved in malolactic fermentation inhibition

An oenological strain of Saccharomyces cerevisiae was previously shown to produce a 5–10 kDa peptidic fraction responsible for the inhibition of malolactic fermentation (MLF). In the present study, we aim to further purify the anti-MLF peptides of this fraction. The yeast fermented synthetic grape juice medium was fractionated by ammonium sulfate precipitation combined with ultrafiltration. The 5–10 kDa fraction recovered at a saturation degree of 60%–80% was the only fraction that inhibited both the bacterial growth and the malate consumption in vivo. It also inhibited the malolactic enzyme activity in vitro at a pH range between 3.5 and 6.7. Therefore, it was purified by both anion and cation exchange chromatography. The eluates that inhibited the malolactic enzyme activity in vitro were migrated on Tricine SDS-PAGE and the protein bands were excised and sequenced by LC-MS/MS. The sequencing revealed nine peptides originating from eight proteins of S. cerevisiae. Two GAPDH cationic fragments of 0.9 and 1.373 kDa having a pI of 10.5 and 11 respectively, Wtm2p and Utr2p anionic fragments of 2.42 kDa with a pI of 3.5 and 4 respectively were thought to contribute the most to the MLF inhibitio

Étude des interactions entre Saccharomyces cerevisiae et Oenococcus oeni (impact sur la réalisation de la fermentation malolactique en cultures séquentielles et mixtes)

Pour une bonne maîtrise de la fermentation malolactique (FML) en vinification, il est important d étudier les différents types d interactions pouvant exister entre les souches de Saccharomyces cerevisiae et d Oenococcus oeni, d identifier les phénomènes et les molécules qui en sont responsables et de définir la façon pertinente de gérer le procédé notamment pour l inoculation de ces souches. Dans ce travail, nous avons testé plusieurs couples levure-bactérie en appliquant deux stratégies d inoculation différentes : cultures séquentielles et co-cultures, dans des milieux synthétiques liquides simulant les milieux naturels. Pour les cultures séquentielles, les bactéries lactiques ont été ensemencées à la fin de la fermentation alcoolique alors que pour les cultures mixtes les levures et les bactéries ont été ensemencées simultanément. La réalisation des cultures séquentielles a permis de quantifier l inhibition ou la stimulation de la FML en fonction des souches sélectionnées dans un couple. Nous avons pu mettre en évidence que l inhibition de la FML peut être en partie due à des peptides inhibiteurs, piste peu exploitée jusqu'à présent. La caractérisation partielle de deux peptides inhibiteurs synthétisés par deux souches de levure a pu être réalisée. Cet effet inhibiteur se rajoute à celui de certaines molécules inhibitrices déjà connues. Comme alternative aux cultures séquentielles, des cultures mixtes de certains couples ont été réalisées dans un bioréacteur à membrane, outil d étude dont l avantage est de séparer physiquement les souches tout en permettant l homogénéisation du milieu. Pour certains couples, la co-inoculation a pu améliorer le rendement de la FML sans risque de déviation. Les résultats montrent que le choix du couple levure-bactérie est un critère très important dans la réussite de la FML. La réalisation de la co-culture peut être intéressante pour certains couples. En revanche une interaction positive a pu être observée pour d autres couples dans le cas de cultures séquentielles. Cette stratégie classique peut alors être conservée.A good control of malolactic fermentation (MLF) during vinification, implies first to study the different kinds of interactions which may occur between Saccharomyces cerevisiae and Oenococcus oeni strains, second to identify the molecules responsible of these interactions and third to define the pertinent way of running the process notably in what concerns the inoculation of these strains. In this work, we have tested several yeast-bacteria couples by applying two different inoculation strategies: the sequential fermentation and the co-culture, using synthetic liquid media which composition simulates natural ones. While during the sequential fermentations, the lactic acid bacteria were inoculated at the end of the alcoholic fermentation; both yeasts and bacteria were inoculated simultaneously during the co-culture. The sequential fermentations allowed us to quantify the inhibition or stimulation of the MLF depending on the choice of the strains within a couple. We have also showed that the inhibition of MLF can be partially due to inhibitory peptides in addition to some classical inhibitory molecules already described. The partial characterization of two inhibitory peptides synthesized by two yeast strains was carried out in this work. This factor has not been intensively investigated till now. As an alternative for sequential fermentations, co-cultures of certain couples were carried out in a membrane bioreactor which advantage was to keep the strains physically separated while the medium was homogenous. For certain couples, the co-culture strategy improved the MLF output without a risk of deviation. Results show that the choice of a yeast-bacteria couple constitutes an important criterion for the success of MLF. The co-culture can be interesting for certain couples. However, a positive interaction was observed with other couples in the case of sequential fermentation. Therefore, this classical strategy has to be maintained.TOULOUSE-ENSIACET (315552325) / SudocSudocFranceF