Fermentative and metabolic screening of candidate yeast strains hybridisable with Saccharomyces cerevisiae for beer production optimisation.

Yeast optimisation has been crucial in improving the quality and efficiency of beer production, one of the world's most widely consumed beverages. In this context, rare mating hybridisation is a promising technique for yeast optimization to generate novel and improved non-GMO strains. The limitation of this technique is the lack of knowledge and comparable data on yeast strains hybridisable to Saccharomyces cerevisiae, probably the most important yeast species in beer production.

Comparative genomics of infective Saccharomyces cerevisiae strains reveals their food origin.

Fungal infections are less studied than viral or bacterial infections and often more difficult to treat. Saccharomyces cerevisiae is usually identified as an innocuous human-friendly yeast; however, this yeast can be responsible for infections mainly in immunosuppressed individuals. S.

Identification and assessment of non-conventional yeasts in mixed fermentations for brewing bioflavored beer.

The increasing demand for more flavored and complex beers encourages the investigation of novel and non-conventional yeasts with the ability to provide a combination of bioflavoring and low ethanol yields. The present study identified 22 yeasts isolated from different brewing sources, including the fermentation by-products known as yeast sludges, and characterized a selection of strains to find the more suitable for the aforementioned aims. HPLC and GC-FID analysis of its brewing products were performed.

A novel aminotransferase gene and its regulator acquired in Saccharomyces by a horizontal gene transfer event.

Background: Horizontal gene transfer (HGT) is an evolutionary mechanism of adaptive importance, which has been deeply studied in wine S. cerevisiae strains, where those acquired genes conferred improved traits related to both transport and metabolism of the nutrients present in the grape must. However, little is known about HGT events that occurred in wild Saccharomyces yeasts and how they determine their phenotypes.

Characterization of kefir yeasts with antifungal capacity against Aspergillus species.

Kefir is a fermented probiotic drink obtained by placing kefir granules in a suitable substrate. The kefir granules are a consortium of bacteria and yeasts embedded in a exopolysaccharide matrix. The aim of this research was the isolation and identification of yeasts from kefir of different origin, the evaluation of their antifungal capacity against Aspergillus spp.

Adaptive evolution in the Saccharomyces kudriavzevii Aro4p promoted a reduced production of higher alcohols.

The use of unconventional yeast species in human-driven fermentations has attracted a lot of attention in the last few years. This tool allows the alcoholic beverage industries to solve problems related to climate change or the consumer demand for newer high-quality products. In this sense, one of the most attractive species is Saccharomyces kudriavzevii, which shows interesting fermentative traits such as the increased and diverse aroma compound production in wines.

The potential role of yeasts in the mitigation of health issues related to beer consumption.

Food consumption of healthier products has become an essential trend in the food sector. This is also the case in beer, a biochemical process of transformation performed by yeast cells. More and more studies proclaim the need to reduce ethanol content in alcoholic drinks, certainly the most important health issue of beer consumption.

Functional divergence in the proteins encoded by ARO80 from S. uvarum, S. kudriavzevii and S. cerevisiae explain differences in the aroma production during wine fermentation.

Phenylethanol (PE) and phenylethyl acetate (PEA) are commonly desired compounds in wine because of their rose-like aroma. The yeast S. cerevisiae produces the PE either through de novo biosynthesis by shikimate pathway followed by the Ehrlich pathway or the direct phenylalanine catabolism via Ehrlich pathway, and then converted into PEA.

Indirect Methods To Measure Unfolded Proteins In Living Cells Using Fluorescent Proteins.

In the study of the unfolded protein response pathway, it is essential to determine the amount of unfolded proteins that the cell is accumulating. Besides being essential it is one of the most challenging technique because of the difficulty to detect unfolded proteins without producing protein denaturation with the method itself. Thus, indirect methods became very useful as the use of fluorescent proteins.

Convergent adaptation of Saccharomyces uvarum to sulfite, an antimicrobial preservative widely used in human-driven fermentations.

Different species can find convergent solutions to adapt their genome to the same evolutionary constraints, although functional convergence promoted by chromosomal rearrangements in different species has not previously been found. In this work, we discovered that two domesticated yeast species, Saccharomyces cerevisiae, and Saccharomyces uvarum, acquired chromosomal rearrangements to convergently adapt to the presence of sulfite in fermentation environments. We found two new heterologous chromosomal translocations in fermentative strains of S.

A Multiphase Multiobjective Dynamic Genome-Scale Model Shows Different Redox Balancing among Yeast Species of the Genus in Fermentation.

Yeasts constitute over 1,500 species with great potential for biotechnology. Still, the yeast Saccharomyces cerevisiae dominates industrial applications, and many alternative physiological capabilities of lesser-known yeasts are not being fully exploited. While comparative genomics receives substantial attention, little is known about yeasts' metabolic specificity in batch cultures.

Metabolic differences between a wild and a wine strain of Saccharomyces cerevisiae during fermentation unveiled by multi-omic analysis.

Saccharomyces cerevisiae, a widespread yeast present both in the wild and in fermentative processes, like winemaking. During the colonization of these human-associated fermentative environments, certain strains of S. cerevisiae acquired differential adaptive traits that enhanced their physiological properties to cope with the challenges imposed by these new ecological niches.

Metabolome segregation of four strains of Saccharomyces cerevisiae, Saccharomyces uvarum and Saccharomyces kudriavzevii conducted under low temperature oenological conditions.

The monitoring of fermentation at low temperatures (12-15°C) is a current practice in the winery for retention and enhancement of the flavour volatile content of wines. Among Saccharomyces species, Saccharomyces uvarum and Saccharomyces kudriavzevii have revealed interesting industrial properties, including better adaptation at low temperatures. To gather deeper knowledge of the fermentative metabolism at a low temperature of these species together with S.

A time course metabolism comparison among Saccharomyces cerevisiae, S. uvarum and S. kudriavzevii species in wine fermentation.

In this study, we presented the first metabolome time course analysis performed among a set of S. uvarum, S. kudriavzevii and S.

Aroma production and fermentation performance of S. cerevisiae × S. kudriavzevii natural hybrids under cold oenological conditions.

This work aims to describe the wine fermentation characteristics of 23 natural S. cerevisiae × S. kudriavzevii hybrid yeasts related to fermentative environments isolated from different regions and their significance for the aroma spectra of the produced wines.

Aneuploidy and Ethanol Tolerance in .

Response to environmental stresses is a key factor for microbial organism growth. One of the major stresses for yeasts in fermentative environments is ethanol. is the most tolerant species in its genus, but intraspecific ethanol-tolerance variation exists.

Dominance of wine Saccharomyces cerevisiae strains over S. kudriavzevii in industrial fermentation competitions is related to an acceleration of nutrient uptake and utilization.

Grape must is a sugar-rich habitat for a complex microbiota which is replaced by Saccharomyces cerevisiae strains during the first fermentation stages. Interest on yeast competitive interactions has recently been propelled due to the use of alternative yeasts in the wine industry to respond to new market demands. The main issue resides in the persistence of these yeasts due to the specific competitive activity of S.

New Trends in the Uses of Yeasts in Oenology.

The most important factor in winemaking is the quality of the final product and the new trends in oenology are dictated by wine consumers and producers. Traditionally the red wine is the most consumed and more popular; however, in the last times, the wine companies try to attract other groups of populations, especially young people and women that prefer sweet, whites or rosé wines, very fruity and with low alcohol content. Besides the new trends in consumer preferences, there are also increased concerns on the effects of alcohol consumption on health and the effects of global climate change on grape ripening and wine composition producing wines with high alcohol content.

A comparison of the performance of natural hybrids Saccharomyces cerevisiae × Saccharomyces kudriavzevii at low temperatures reveals the crucial role of their S. kudriavzevii genomic contribution.

Fermentation performance at low temperature is a common approach to obtain wines with better aroma, and is critical in industrial applications. Natural hybrids S. cerevisiae × S.

Membrane fluidification by ethanol stress activates unfolded protein response in yeasts.

The toxic effect of ethanol is one of the most important handicaps for many biotechnological applications of yeasts, such as bioethanol production. Elucidation of ethanol stress response will help to improve yeast performance in biotechnological processes. In the yeast Saccharomyces cerevisiae, ethanol stress has been recently described as an activator of the unfolded protein response (UPR), a conserved intracellular signalling pathway that regulates the transcription of ER homoeostasis-related genes.

Transcriptomic analysis of x hybrids during low temperature winemaking.

Background: Although is the most frequently isolated species in wine fermentation, and the most studied species, other species and interspecific hybrids have greatly attracted the interest of researchers in this field in the last few years, given their potential to solve new winemaking industry challenges. x hybrids exhibit good fermentative capabilities at low temperatures, and produce wines with smaller alcohol quantities and larger glycerol quantities, which can be very useful to solve challenges in the winemaking industry such as the necessity to enhance the aroma profile.

Methods: In this study, we performed a transcriptomic study of x hybrids in low temperature winemaking conditions.

On the origins and industrial applications of Saccharomyces cerevisiae × Saccharomyces kudriavzevii hybrids.

Companies based on alcoholic fermentation products, such as wine, beer and biofuels, use yeasts to make their products. Each industrial process utilizes different media conditions, which differ in sugar content, the presence of inhibitors and fermentation temperature. Saccharomyces cerevisiae has traditionally been the main yeast responsible for most fermentation processes.

show low levels of traversal across human endothelial barrier .

:   is generally considered safe, and is involved in the production of many types of foods and dietary supplements. However, some isolates, which are genetically related to strains used in brewing and baking, have shown virulent traits, being able to produce infections in humans, mainly in immunodeficient patients. This can lead to systemic infections in humans.

RNAseq-based transcriptome comparison of Saccharomyces cerevisiae strains isolated from diverse fermentative environments.

Transcriptome analyses play a central role in unraveling the complexity of gene expression regulation in Saccharomyces cerevisiae. This species, one of the most important microorganisms for humans given its industrial applications, shows an astonishing degree of genetic and phenotypic variability among different strains adapted to specific environments. In order to gain novel insights into the Saccharomyces cerevisiae biology of strains adapted to different fermentative environments, we analyzed the whole transcriptome of three strains isolated from wine, flor wine or mezcal fermentations.