Yeast interactions and wine flavour.

Saccharomyces cerevisiae-Oenococcus oeni interactions in wine: current knowledge and perspectives.

Malolactic fermentation (MLF) is a secondary wine fermentation conducted by lactic acid bacteria (LAB). This fermentation is important in winemaking as it deacidifies the wine, it contributes to microbial stability and lastly it contributes to wine aroma through the production of metabolites. Oenococcus oeni is the main species used in commercially available starter culture currently, but research has indicated that different Lactobacillus species also partake in MLF and this has shifted the focus in the MLF field to evaluate the potential of lactobacilli as starter cultures for the future. There are 17 different species of Lactobacillus associated with winemaking either being associated with the grapes/beginning of alcoholic fermentation or the MLF and wine. Lactobacillus associated with wine is mainly facultative or obligatory heterofermentative and can withstand the harsh wine conditions such as high ethanol levels, low pH and temperatures and sulphur dioxide. Wine lactobacilli contain the malolactic enzyme encoding gene, but sequence homology shows that it clusters separate from O. oeni. Lactobacillus also possesses more enzyme encoding genes compared to O. oeni, important for the production of wine aroma compounds such as glycosidase, protease, esterase, phenolic acid decarboxylase and citrate lyase. Another characteristic associated with wine lactobacilli is the production of bacteriocins, especially plantaricins which would enable them to combat spoilage LAB. All these characteristics, together with their ability to conduct MLF just as efficiently as O. oeni, make them suitable for a new generation of MLF starter cultures.

Lactobacillus : the Next Generation of Malolactic Fermentation Starter Cultures—an Overview

Most fermented products are generated by a mixture of microbes. These microbial consortia perform various biological activities responsible for the nutritional, hygienic, and aromatic qualities of the product. Wine is no exception. Substantial yeast and bacterial biodiversity is observed on grapes, and in both must and wine. The diverse microorganisms present interact throughout the winemaking process. The interactions modulate the hygienic and sensorial properties of the wine. Many studies have been conducted to elucidate the nature of these interactions, with the aim of establishing better control of the two fermentations occurring during wine processing. However, wine is a very complex medium making such studies difficult. In this review, we present the current state of research on microbial interactions in wines. We consider the different kinds of interactions between different microorganisms together with the consequences of these interactions. We underline the major challenges to obtaining a better understanding of how microbes interact. Finally, strategies and methodologies that may help unravel microbe interactions in wine are suggested.

Wine microbiome: A dynamic world of microbial interactions

The Commercial and Community Significance of Yeasts in Food and Beverage Production.- Taxonomic and Ecological Diversity of Food and Beverage Yeasts.- Molecular Methods to Identify and Characterize Yeasts in Foods and Beverages.- Yeast Ecological Interactions. Yeast'Yeast, Yeast'Bacteria, Yeast'Fungi Interactions and Yeasts as Biocontrol Agents.- Physiological and Molecular Responses of Yeasts to the Environment.- Molecular Mechanisms Involved in the Adaptive Evolution of Industrial Yeasts.- Principles and Applications of Genomics and Proteomics in the Analysis of Industrial Yeast Strains.- Carbohydrate Metabolism.- Yeasts as Biocatalysts.- Production of Antioxidants, Aromas, Colours, Flavours, and Vitamins by Yeasts.- Food and Beverage Spoilage Yeasts.- The Public Health and Probiotic Significance of Yeasts in Foods and Beverages.- The Development of Superior Yeast Strains for the Food and Beverage Industries: Challenges, Opportunities and Potential Benefits.

Yeasts in food and beverages

Substances with antibacterial activity were recovered from the extracellular medium and from the acidified cell extract of Saccharomyces cerevisiae R107 by binding onto a cation exchanger. The fraction eluted with NaOH contained two different antibacterial factors, one with the characteristics of lysozyme, the other apparently a small protein with a similar high pI. Die Isolierung von zwei bakteriziden, kationischen Proteinen aus Saccharomyces cerevisiae , die Bakterien des Saureabbaus hemmen Substanzen mit bakterizider Wirkung wurden sowohl aus dem Kultursubstrat als auch aus angesauertem Zellextrakt von Saccharomyces cerevisiae Rl07 mit Hilfe von Kationenaustauscher isoliert. Die mit NaOH eluierte Fraktion enthielt zwei unterschiedliche bakterizide Substanzen, eine mit Lysozymeigenschaften, die andere, ein kleines Protein, mit ahnlich hohem isoelektrischen Punkt.

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R. Eschenbruch

Papers

The isolation from Saccharomyces cerevisiae of two antibacterial cationic proteins that inhibit malolactic bacteria