Search results for "Malolactic Fermentation"
showing 8 items of 78 documents
Exoenzymes of Wine Microorganisms
2008
The production of wine from grape juice is predominantly the result of enzymatic reactions. The enzymes originate from the grape itself, from epiphytic fungi like Botrytis cinerea colonizing the grape surface and finally from yeasts and bacteria growing in the must until termination of alcoholic fermentation. Especially nonSaccharomyces yeasts, also called “wild” yeasts, belonging to the genera Kloeckera, Candida, Debaryomyces, Rhodotorula, Pichia, Zygosaccharomyces, Hanseniaspora, Kluyveromyces, and Metschnikowia produce and secrete several enzymes (esterases, glycosidases, lipases, glucanases, proteases, cellulases, etc.) to the periplasmatic space and the medium where they may interact w…
Yeast-Bacteria Coinoculation
2019
Abstract Yeasts and lactic acid bacteria (LAB) coinoculation is the simultaneous, or close in time inoculation, of both types of microorganisms in winemaking. Coinoculation has been used mainly to early accomplish malolactic fermentation (MLF), employing generally the couples Oenococcus oeni/Saccharomyces cerevisiae and Lactobacillus plantarum/S. cerevisiae. Early completion of MLF decreases the overall vinification time, reduces the microbial spoilage risk, and even prevents the biogenic amines synthesis. LAB/yeasts coinoculation could be also used to increase the acidity of wines when inoculated in grape must, using sugar to synthesize lactic acid and producing ethanol diminution. Coinocu…
Application of MALDI-TOF-MS and nested SAPD-PCR for discrimination ofOenococcus oeniisolates at the strain level
2015
Oenococcus oeni is the most important lactic acid bacterium during vinification and is frequently used as a commercial starter culture for malolactic fermentation. Since different strains exhibit a high heterogeneity concerning wine-related physiological characteristics, reliable methods for their differentiation at the strain level are needed, especially for the development of starter cultures. Microbial identification by using matrix-assisted laser desorption ionization time-of-flight mass spectrometry (MALDI-TOF-MS) has increased over the last few years. In the present study, we used MALDI-TOF-MS for the differentiation of 11 O. oeni isolates originating from 5 different wine-growing reg…
2-Oxoglutarate decarboxylase ofLeuconostoc oenos
1990
InLeuconostoc oenos, the typical organism of the malolactic fermentation of wine, a 2-oxoglutarate decarboxylase was detected. This inducible enzyme decarboxylates 2-oxoglutarate but not pyruvate. The resulting succinaldehydate is rapidly reduced to 4-hydroxybutyrate or oxidized to succinate in further reactions. 2-Oxoglutarate decarboxylase is thiamin-diphosphate-dependent; the pH optimum is at 5.3 and theK m value for 2-oxoglutarate is 1.8 mmol/L.
Influence of fatty acids on the growth of wine microorganisms Saccharomyces cerevisiae and Oenococcus oeni
1998
The effects of fatty acids, extracted during prefermentation grape skin-contact on Saccharomyces cerevisiae and Oenococcus oeni, were studied. The influence of skin-contact on total fatty acid content was evaluated both in Chardonnay must and in synthetic medium. Prior to alcoholic fermentation, the skin-contact contributes to a large enrichment of long-chain fatty acids (C 16 to C 18:3 ). These results induced a positive effect on yeast growth and particularly on cell viability. In the skin-contact fermented media, levels of C 12 and especially C 10 are lower and macromolecules content higher than in controls. This production of extracellular mannoproteins and the reduction of medium-chain…
Lactic Acid Bacteria in Spanish Red Rose and White Musts and Wines under Cellar Conditions
1992
The dynamics of the lactic acid bacterial (LAB) population in different cellars, fermentation conditions and musts were analyzed. The number of LAB in fresh musts diminished quickly in the first few days, but an increase of these bacteria occurred during the later stages of the alcoholic fermentation. The species found in fresh musts were Lactobacillus plantarum, L. hilgardii, L. brevis, L. confusus, and Leuc. onostoc paramesenteroides. At the end of fermentation only L. hilgardii, Leuc. oenos and L. fructivorans were isolated. The API 50 CHL system was not useful to identify strains of Leuc. oenos species. All the isolated strains degraded malic acid in synthetic medium but only two strain…
Chemical Transfers Occurring Through
2019
Chardonnay wine malolactic fermentations were carried out to evaluate the chemical transfers occurring at the wood/wine interface in the presence of two different bacterial lifestyles. To do this, Oenococcus oeni was inoculated into must and wine in its planktonic and biofilm lifestyles, whether adhering or not to oak chips, leading to three distinct enological conditions: (i) post-alcoholic fermentation inoculation in wine in the absence of oak chips, (ii) post-alcoholic fermentation inoculation in wine in the presence of oak chips, and (iii) co-inoculation of both Saccharomyces cerevisiae and O. oeni directly in Chardonnay musts in the presence of oak chips. Classical microbiological and …
Regulation of hdc expression and HDC activity by enological factors in lactic acid bacteria.
2008
Aims: The aim of this work was to study the influence of enological factors on the histidine decarboxylase gene (hdc) expression and on histidine decarboxylase enzyme (HDC) activity in Lactobacillus hilgardii, Pediococcus parvulus and Oenococcus oeni. Methods and Results: Cell extracts and whole cells were used. Glucose, fructose, malic acid and citric acid diminished the hdc expression. Ethanol did not increase hdc expression or activity in cells, but increased HDC activity. Temperature and pH had effect on the activity of HDC but not on hdc expression. Tartaric acid and l-lactic acid, and sulphur dioxide (SO2) had no effect on enzyme synthesis and activity. Bacterial species differ in t…