Search results for " saccharomyces"
showing 10 items of 42 documents
Technological properties of Lactobacillus plantarum strains isolated from grape must fermentation
2016
Malolactic fermentation (MLF) is a secondary fermentation in wine that usually takes place during or at the end of alcoholic fermentation. Lactobacillus plantarum is able to conduct MLF (particularly under high pH conditions and in co-inoculation with yeasts) and some strains are commercially used as MLF starter cultures. Recent evidences suggest a further use of selected L. plantarum strains for the pre-alcoholic acidification of grape must. In this study, we have carried out an integrated (molecular, technological, and biotechnological) characterization of L. plantarum strains isolated from Apulian wines in order to combine the two protechnological features (MLF performances and must acid…
Starter cultures as biocontrol strategy to prevent Brettanomyces bruxellensis proliferation in wine
2017
Brettanomyces bruxellensis is a common and significant wine spoilage microorganism. B. bruxellensis strains generally detain the molecular basis to produce compounds that are detrimental for the organoleptic quality of the wine, including some classes of volatile phenols that derive from the sequential bioconversion of specific hydroxycinnamic acids such as ferulate and p-coumarate. Although B. bruxellensis can be detected at any stage of the winemaking process, it is typically isolated at the end of the alcoholic fermentation (AF), before the staring of the spontaneous malolactic fermentation (MLF) or during barrel aging. For this reason, the endemic diffusion of B. bruxellensis leads to c…
A Metagenomic-Based Approach for the Characterization of Bacterial Diversity Associated with Spontaneous Malolactic Fermentations in Wine
2019
This study reports the first application of a next generation sequencing (NGS) analysis. The analysis was designed to monitor the effect of the management of microbial resources associated with alcoholic fermentation on spontaneous malolactic consortium. Together with the analysis of 16S rRNA genes from the metagenome, we monitored the principal parameters linked to MLF (e.g., malic and lactic acid concentration, pH). We encompass seven dissimilar concrete practices to manage microorganisms associated with alcoholic fermentation: Un-inoculated must (UM), pied-de-cuve (PdC), Saccharomyces cerevisiae (SC), S. cerevisiae and Torulaspora delbrueckii co-inoculated and sequentially inoculated, as…
Use of autochthonous yeasts and bacteria in order to control Brettanomyces bruxellensis in wine
2017
Biocontrol strategies for the limitation of undesired microbial developments in foods and beverages represent a keystone toward the goal of more sustainable food systems. Brettanomyces bruxellensis is a wine spoilage microorganism that produces several compounds that are detrimental for the organoleptic quality of the wine, including some classes of volatile phenols. To control the proliferation of this yeast, sulfur dioxide is commonly employed, but the efficiency of this compound depends on the B. bruxellensis strain; and it is subject to wine composition and may induce the entrance in a viable, but nonculturable state of yeasts. Moreover, it can also elicit allergic reactions in humans. …
Evolution of yeast populations during different biodynamic winemaking processes
2016
This work was performed to evaluate the evolution of indigenous yeasts during wine productions carried out following the principles of biodynamic agriculture. Five trials were designed with different technological interventions consisting of the addition of nitrogen (in the form of ammonium salt), thiamine salt, oxygen, and pied de cuvee at varying concentrations. Yeasts were estimated by haemocytometer chamber and plate counts and identified by sequencing of the D1/D2 domain of the 26S rRNA gene. The isolates identified as Saccharomyces cerevisiae were found to dominate must fermentations and were genetically differentiated by interdelta sequence analysis (ISA). Several non-Saccharomyces s…
A method to discriminate between the Candida stellata and Saccharomyces cerevisiae in mixed fermentation on WLD and lysine agar media
2016
This paper presents a simple method to distinguish between Candida stellata and Saccharomyces cerevisiae yeasts during microbiological analyses. The method is based on differential yeast growth on a medium containing cycloheximide and a medium containing lysine as only nitrogen source (lysine agar). The cycloheximide resistance of 45 yeast strains belonging to Candida stellata, Hanseniaspora uvarum, Hanseniaspora guilliermondii, Metschnikowia pulcherrima, Torulaspora delbrueckii, Zygosaccharomyces bailii, Kluyveromyces thermotolerans and Zygoascus hellenicus, and 14 strains of Saccharomyces cerevisiae and Saccharomyces bayanus on WL nutrient agar, was assayed. Cycloheximide resistance is ch…
The Wine: typicality or mere diversity? The effect of spontaneous fermentations and biotic factors on the characteristics of wine
2016
Abstract Wine is probably one of the main fermented beverages for which the recognition of the “territoriality” is fundamental for its appreciation. The sensory profile of wine is significantly affected by microbial activities, and indigenous microorganisms may significantly contribute to the expression of wine typicality. The microbial ecology of wines is complex and includes several species and strains of yeasts, bacteria and molds. Several works showed the positive effects of spontaneous fermentations on the quality of wine as a consequence of the growth of different species and/or strains together at high levels. Furthermore, a new style of “natural” winemaking is gaining importance, si…
Wine yeast sirtuins and Gcn5p control aging and metabolism in a natural growth medium.
2012
Grape juice fermentation by wine yeast is an interesting model to understand aging under conditions closer to those in nature. Grape juice is rich in sugars and, unlike laboratory conditions, the limiting factor for yeast growth is nitrogen. We tested the effect of deleting sirtuins and several acetyltransferases to find that the role of many of these proteins during grape juice fermentation is the opposite to that under standard laboratory aging conditions using synthetic complete media. For instance, . SIR2 deletion extends maximum chronological lifespan in wine yeasts grown under laboratory conditions, but shortens it in winemaking. Deletions of sirtuin . HST2 and acetyltransferase . GCN…
Evolution of microbiological and chemical parameters during red wine making with extended post-fermentation maceration.
2014
Abstract The aim of the present work was to investigate the microbiological, chemical, and sensory characteristics of red wine subjected to post-fermentation maceration that was extended to 90 days. For this purpose, the ‘Aglianico di Taurasi’ grape was used as a case study. The total yeast concentration increased until day 40 of maceration and decreased thereafter, whereas the concentration of lactic acid bacteria slightly increased. Dekkera/Brettanomyces spp. and acetic acid bacteria were not detected. The yeast community was composed of Saccharomyces cerevisiae, Zygosaccharomyces bisporus, Metschnikowia pulcherrima, Hanseniaspora guilliermondii, Hanseniaspora uvarum, Pichia guilliermondi…
Cell volume homeostatically controls the rDNA repeat copy number and rRNA synthesis rate in yeast
2021
[Abstract] The adjustment of transcription and translation rates to the changing needs of cells is of utmost importance for their fitness and survival. We have previously shown that the global transcription rate for RNA polymerase II in budding yeast Saccharomyces cerevisiae is regulated in relation to cell volume. Total mRNA concentration is constant with cell volume since global RNApol II-dependent nascent transcription rate (nTR) also keeps constant but mRNA stability increases with cell size. In this paper, we focus on the case of rRNA and RNA polymerase I. Contrarily to that found for RNA pol II, we detected that RNA polymerase I nTR increases proportionally to genome copies and cell s…