Does Fungal Chitosan Leave Noticeable Traces in Treated Wines?

The use of fungal chitosan as an antiseptic in wine appears as a promising alternative to sulfur dioxide for the elimination of sensitive strains. Nevertheless, its utilization raises the question, "how are the treated wines different from the untreated ones?" Chitosan treatment residues were sought in the oligosaccharide and polysaccharide fractions and among 224 low MW ions (<1800 g·mol) in several wines by using liquid chromatography (size exclusion HPLC or LC-MS) and GC-MS. Standard oenological parameters were also examined as well as possible sensory modifications by a panel of tasters composed of experts and non-experts.

Effect of abiotic and biotic factors on Brettanomyces bruxellensis bioadhesion properties.

Biofilms are central to microbial life because of the advantage that this mode of life provides, whereas the planktonic form is considered to be transient in the environment. During the winemaking process, grape must and wines host a wide diversity of microorganisms able to grow in biofilm. This is the case of Brettanomyces bruxellensis considered the most harmful spoilage yeast, due to its negative sensory effect on wine and its ability to colonise stressful environments.

Application of white wine lees for promoting lactic acid bacteria growth and malolactic fermentation in wine.

In the context of ecological transition, the use of wine by-products for industrial applications is a major challenge. Wine lees, the second wine by-product in terms of quantity, represent a source of nutrients that can be used for stimulating the growth of microorganisms. Here, white wine lees were used as a stimulating agent for the growth of wine lactic acid bacteria (LAB) and to promote wine malolactic fermentation (MLF) driven out by Oenococcus oeni.

Alcoholic fermentation drives the selection of Oenococcus oeni strains in wine but not in cider.

Oenococcus oeni is the predominant lactic acid bacteria species in wine and cider, where it performs the malolactic fermentation (MLF). The O. oeni strains analyzed to date form four major genetic lineages named phylogroups A, B, C and D.

High intraspecific variation of the cell surface physico-chemical and bioadhesion properties in Brettanomyces bruxellensis.

Brettanomyces bruxellensis is the most damaging spoilage yeast in the wine industry because of its negative impact on the wine organoleptic qualities. The strain persistence in cellars over several years associated with recurrent wine contamination suggest specific properties to persist and survive in the environment through bioadhesion phenomena. In this work, the physico-chemical surface properties, morphology and ability to adhere to stainless steel were studied both on synthetic medium and on wine.

Evaluating the influence of operational parameters of pulsed light on wine related yeasts: focus on inter- and intra-specific variability sensitivity.

In oenology, there is a growing demand by consumers for wines produced with less inputs (such as sulphite, frequently used for microbial control). Emerging control methods for managing microorganisms in wine are widely studied. In this study, the efficiency of pulsed light (PL) treatment was investigated.

Assessment of chitosan antimicrobial effect on wine microbes.

Chitosan is an active highly charged polysaccharide that has initially been developed in oenology to eliminate the spoilage yeast B. bruxellensis. However, different forms of chitosan exist, some complying with EU regulation for their use in wines, others not.

Brettanomyces bruxellensis: Overview of the genetic and phenotypic diversity of an anthropized yeast.

Human-associated microorganisms are ideal models to study the impact of environmental changes on species evolution and adaptation because of their small genome, short generation time, and their colonization of contrasting and ever-changing ecological niches. The yeast Brettanomyces bruxellensis is a good example of organism facing anthropogenic-driven selective pressures. It is associated with fermentation processes in which it can be considered either as a spoiler (e.

Wine yeast species show strong inter- and intra-specific variability in their sensitivity to ultraviolet radiation.

While the trend in winemaking is toward reducing the inputs and especially sulphites utilization, emerging technologies for the preservation of wine is a relevant topic for the industry. Amongst yeast spoilage in wine, Brettanomyces bruxellensis is undoubtedly the most feared. In this study, UV-C treatment is investigated.

Reliability of MALDI-TOF mass spectrometry to identify oral isolates of Streptococcus salivarius and Lactobacillus spp.

Objective: The aim of this study is to evaluate the performance of MALDI-TOF mass spectrometry in identifying bacteria isolated in the oral cavity known to be of probiotic interest.

Design: We evaluated Bruker MALDI Biotyper for the identification of 92 clinical oral isolates of probiotic interest (31 Streptococcus salivarius and 61 Lactobacillus spp.) by comparing direct colony method with on-plate formic acid extraction.

+ Displays Variable Susceptibility to Chitosan Treatment in Wine.

is the main spoilage microbial agent in red wines. The use of fungal chitosan has been authorized since 2009 as a curative treatment to eliminate this yeast in conventional wines and in 2018 in organic wines. As this species is known to exhibit great genetic and phenotypic diversity, we examined whether all the strains responded the same way to chitosan treatment.

Carbohydrate composition of red wines during early aging and incidence on spoilage by Brettanomyces bruxellensis.

Wine is generally considered as hostile medium in which spoilage microbes have to manage with many abiotic factors among which low nutrient content. Wines elaborated in 8 wineries were sampled during the first summer of aging over two consecutive vintages, and analysed for carbohydrate composition. This revealed the systematic presence of many carbohydrates including those useful for the spoilage yeast Brettanomyces bruxellensis.

Influence of must yeast-assimilable nitrogen content on fruity aroma variation during malolactic fermentation in red wine.

This study assessed the impact of must yeast-assimilable nitrogen (YAN) content and lactic acid bacteria (LAB) strains used for malolactic fermentation (MLF) on the formation of substituted esters, as well as the corresponding precursors (substituted acids), to investigate the modulation of fruity expression in red wines. In microvinification experiments, a Merlot must was fermented with an initial YAN content of 111 mg/L, or supplemented up to 165 and 220 mg/L. Two Oenococcus oeni LAB strains were used for MLF.

Brettanomyces bruxellensis phenotypic diversity, tolerance to wine stress and wine spoilage ability.

Brettanomyces bruxellensis is a yeast species found in many fermented matrices. A high level of genetic diversity prevails in this species and was recently connected with tolerance to sulfur dioxide, the main preservative used in wine. We therefore examine other phenotypes that may modulate the ability of the species to spoil wine, in a selection of representative strains.

Brettanomyces bruxellensis wine isolates show high geographical dispersal and long persistence in cellars.

Brettanomyces bruxellensis is the main wine spoiler yeast all over the world, yet the structure of the populations associated with winemaking remains elusive. In this work, we considered 1411 wine isolates from 21 countries that were genotyped using twelve microsatellite markers. We confirmed that B.

Correction for Rosa et al., "Draft Genome Sequence of the (syn., ) Type Strain CBS 9494".

[This corrects the article DOI: 10.1128/MRA.00872-18.

Draft Genome Sequence of the Candida zemplinina (syn., Starmerella bacillaris) Type Strain CBS 9494 [corrected].

Starmerella bacillaris is an ascomycetous yeast ubiquitously present in grapes and fermenting grape musts. In this report, we present the draft genome sequence of the S. bacillaris type strain CBS 9494, isolated from sweet botrytized wines, which will contribute to the study of this genetically heterogeneous wine yeast species.

Exopolysaccharide Biosynthesis, a Tool to Improve Malolactic Starter Performance.

is the lactic acid bacterium that most commonly drives malolactic fermentation (MLF) in wine. Though the importance of MLF in terms of wine microbial stability and sensory improvement is well established, it remains a winemaking step not so easy to control. displays many adaptation tools to resist the harsh wine conditions which explain its natural dominance at this stage of winemaking.

Combined effect of the Saccharomyces cerevisiae lag phase and the non-Saccharomyces consortium to enhance wine fruitiness and complexity.

Non-Saccharomyces (NS) species that are either naturally present in grape must or added in mixed fermentation with S. cerevisiae may impact the wine's chemical composition and sensory properties. NS yeasts are prevailing during prefermentation and early stages of alcoholic fermentation.

Molecular Cloning, Expression and Characterization of Oenococcus oeni Priming Glycosyltransferases.

Oenococcus oeni is the main bacterial species that drives malolactic fermentation in wine. Most O. oeni strains produce capsular exopolysaccharides (EPS) that may contribute to protect them in the wine hostile environment.

Hanseniaspora uvarum from Winemaking Environments Show Spatial and Temporal Genetic Clustering.

Hanseniaspora uvarum is one of the most abundant yeast species found on grapes and in grape must, at least before the onset of alcoholic fermentation (AF) which is usually performed by Saccharomyces species. The aim of this study was to characterize the genetic and phenotypic variability within the H. uvarum species.

A new method for monitoring the extracellular proteolytic activity of wine yeasts during alcoholic fermentation of grape must.

The existing methods for testing proteolytic activity are time consuming, quite difficult to perform, and do not allow real-time monitoring. Proteases have attracted considerable interest in winemaking and some yeast species naturally present in grape must, such as Metschnikowia pulcherrima, are capable of expressing this activity. In this study, a new test is proposed for measuring proteolytic activity directly in fermenting grape must, using azocasein, a chromogenic substrate.

The yeast Starmerella bacillaris (synonym Candida zemplinina) shows high genetic diversity in winemaking environments.

The yeast Candida zemplinina (Starmerella bacillaris) is frequently isolated from grape and wine environments. Its enological use in mixed fermentation with Saccharomyces cerevisiae has been extensively investigated these last few years, and several interesting features including low ethanol production, fructophily, glycerol and other metabolites production, have been described. In addition, molecular tools allowing the characterization of yeast populations have been developed, both at the inter- and intraspecific levels.

Development of microsatellite markers for the rapid and reliable genotyping of Brettanomyces bruxellensis at strain level.

Although many yeasts are useful for food production and beverage, some species may cause spoilage with important economic loss. This is the case of Dekkera/Brettanomyces bruxellensis, a contaminant species that is mainly associated with fermented beverages (wine, beer, cider and traditional drinks). To better control Brettanomyces spoilage, rapid and reliable genotyping methods are necessary to determine the origins of the spoilage, to assess the effectiveness of preventive treatments and to develop new control strategies.