Project description:Oenococcus oeni is the main lactic acid bacterium that carries out the malolactic fermentation in virtually all red wines and in some white and sparkling wines. O. oeni possesses an array of metabolic activities which can modify the taste and aromatic properties of wine. There is therefore industrial interest in the proteins involved in these metabolic pathways and related transport systems of this bacterium. In this work, we report the characterization of the O. oeni ATCC BAA-1163 proteome. Total and membrane protein preparations from O. oeni were standardized and analyzed by two-dimensional gel electrophoresis. Using tandem mass spectrometry we identified 226 different polypeptides corresponding to 155 unique proteins, which have been classified by their putative function and subjected to bioinformatics analysis.
Project description:The correct development of malolactic fermentation depends on the capacity of Oenococcus oeni to survive under harsh wine conditions. In this study it was characterized the transcriptomic response of O. oeni PSU-1 during the adaptation to wine-like medium (WLM). The period evaluated was from the inoculation into WLM (12% v/v pH 3.4) until the beginning of malolactic fermentation (8h after inoculation).
Project description:The yeast Saccharomyces cerevisiae is an important component of the wine fermentation process and determines various attributes of the final product. However, lactic acid bacteria (LAB) are also an integral part of the microflora of any fermenting must. Various wine microorganism engineering projects have been endeavoured in the past in order to change certain wine characteristics, namely aroma compound composition, ethanol concentration, levels of toxic/ allergenic compounds etc. Most of these projects focus on a specific gene or pathway, whereas our approach aims to understand the genetically complex traits responsible for these phenotypes in a systematic manner by implementing a transcriptomic analysis of yeast in mixed fermentations with the LAB O. oeni. Our aim is to investigate interactions between yeast and LAB on a gene expression level to identify targets for modification of yeast and O. oeni in a directed manner. Our goal was to identify the impact that the common wine microorganism O. oeni (malolactic bacteria) has on fermenting yeast cells on a gene expression level. To this end we co-inoculated the yeast and bacteria at the start of fermentation in a synthetic wine must, using yeast-only fermentations witout O. oeni as a control. Fermentations were carried out in synthetic wine must in triplicate for both the control S. cerevisiae VIN13 strain and the mixed fermentation of VIN13 and O. oeni (strain S5). Sampling of yeast for RNA extractions were performed at day 3 of fermentation, during the exponential growth phase of the yeast cells, and again at day 7 of fermentation, during the early stationary growth phase.
Project description:In this work, three O.oeni strians were inoculated, two of them were of our own collection (3P2 and 2T2) and the other one is the type strain 217T (=ATCC 23279) in WLM-12 to develop MLF in these conditions (Bordas et al, 2015). Basic fermentation characteristics were monitored, such as growth rate and biomass yield, as well as the respective transcriptome. This approach allowed a better understanding of metabolic adaptation and its association with specific genes expression profiles, likewise we were able to identify some biological process directly involved in the fermentation conditions such as pH or ethanol content.
Project description:Our study involves a transcriptomic approach to the analysis of industrial yeast metabolism. Historically, among the hundreds of yeast species, Saccharomyces cerevisiae has played an important role in scientific investigations and industrial applications, and it is universally acknowledged as one of the model systems for eukaryotic organisms. Yeast is also an important component of the wine fermentation process and determines various attributes of the final product. Our research takes a holistic approach to the improvement of industrial yeast strains by integrating large data sets from various yeast strains during fermentation. This means that analysis can be done in such a way as to co-evaluate several parameters simultaneously to identify points of interest and target genes for metabolic engineering. Eventually we hope to construct an accurate information matrix and a more complete cellular map for the fermenting yeast. This will enable accurate model-building for industrial yeast and facilitated the design of intelligent yeast improvement strategies which can be applied via traditional avenues of molecular biology. Experiment Overall Design: Five different Saccharomyces cerevisiae strains used in industrial winemaking processes were used in synthetic must (MS300) fermentations. All fermentations were carried out in triplicate, so each sample is represented by three completely independent biological repeats. Samples for microarray analysis were taken at three different time points during fermentation, representative of the exponential (day2), early stationary (day5) and late stationary (day14) growth stages.
Project description:The yeast Saccharomyces cerevisiae is an important component of the wine fermentation process and determines various attributes of the final product. However, lactic acid bacteria (LAB) are also an integral part of the microflora of any fermenting must. Various wine microorganism engineering projects have been endeavoured in the past in order to change certain wine characteristics, namely aroma compound composition, ethanol concentration, levels of toxic/ allergenic compounds etc. Most of these projects focus on a specific gene or pathway, whereas our approach aims to understand the genetically complex traits responsible for these phenotypes in a systematic manner by implementing a transcriptomic analysis of yeast in mixed fermentations with the LAB O. oeni. Our aim is to investigate interactions between yeast and LAB on a gene expression level to identify targets for modification of yeast and O. oeni in a directed manner. Our goal was to identify the impact that the common wine microorganism O. oeni (malolactic bacteria) has on fermenting yeast cells on a gene expression level. To this end we co-inoculated the yeast and bacteria at the start of fermentation in a synthetic wine must, using yeast-only fermentations witout O. oeni as a control.