Cerevisiae Yeast Research Articles

Impact of Encapsulated Saccharomyces cerevisiae Yeasts on the Chemical and Sensory Profiles of Sparkling Cider Produced by the Champenoise Method

The cider market has been significantly expanding and gaining momentum in Eastern Europe. As such, the aim of this study was to obtain sparkling cider via the Champenoise method using two Romanian apple varieties (Topaz and Red Topaz) alongside the employment of two fermentations. Four yeast strains were used in the first fermentation, while encapsulated Saccharomyces cerevisiae was used in the second fermentation. The resulting cider was subjected to a comprehensive investigation to quantitatively determine the carbohydrates, organic acids, volatile and phenolic compounds, and amino acids from all the cider samples. A trained panel evaluated the sensory profile of the samples, and a chemometric analysis was used to interpret the data. Secondary fermentation increased the accumulation of malic acid and lactic acid, as well as the volatile profile complexity. The total polyphenol content in the sparkling cider samples increased by almost 20% in the S. cerevisiae sample and over 217% in the P. kluyveri + S. cerevisiae sample compared to the base cider. Additionally, studying the production and consumption trends of sparkling cider offers valuable insights for both producers and consumers. By understanding consumer preferences and refining production techniques, the industry can deliver higher-quality products that better align with market demands.

Reduction of Ferric Chloride in Yeast Growth Media, by Sugars and Aluminum

Iron compounds can be used in antimicrobial applications by exploiting the toxicity of divalent iron to living organisms due to the Fenton reaction. In this study, the growth inhibitory effects of ferrous sulfate FeSO4·7H2O and ferric chloride FeCl3·6H2O were observed on Metschnikowia clade and Saccharomyces cerevisiae yeast cells. The relatively high amount of reduced Fe3+ to Fe2+ in the growth medium determined by Mössbauer spectroscopy may contribute to the antimicrobial activity of ferric chloride. In order to test the reducing ability of sugars in the growth media of yeasts, the reaction of ferric chloride FeCl3·6H2O with sugars was investigated. In mixtures of FeCl3·6H2O and fructose, approximately two thirds of Fe3+ can be reduced to Fe2+. When the mixture of FeCl3·6H2O and fructose is placed on the surface of aluminum foil, an iron film is formed on the surface of the aluminum due to the reduction by both fructose and aluminum. The relative amount of Fe3+ which was reduced to Fe0 reached 68%.

Species-wide quantitative transcriptomes and proteomes reveal distinct genetic control of gene expression variation in yeast

Gene expression varies between individuals and corresponds to a key step linking genotypes to phenotypes. However, our knowledge regarding the species-wide genetic control of protein abundance, including its dependency on transcript levels, is very limited. Here, we have determined quantitative proteomes of a large population of 942 diverse natural Saccharomyces cerevisiae yeast isolates. We found that mRNA and protein abundances are weakly correlated at the population gene level. While the protein coexpression network recapitulates major biological functions, differential expression patterns reveal proteomic signatures related to specific populations. Comprehensive genetic association analyses highlight that genetic variants associated with variation in protein (pQTL) and transcript (eQTL) levels poorly overlap (3%). Our results demonstrate that transcriptome and proteome are governed by distinct genetic bases, likely explained by protein turnover. It also highlights the importance of integrating these different levels of gene expression to better understand the genotype-phenotype relationship.

Virtually identical does not mean exactly identical: Discrepancy in energy metabolism between glucose and fructose fermentation influences the reproductive potential of yeast cells

The physiological efficiency of cells largely depends on the possibility of metabolic adaptations to changing conditions, especially on the availability of nutrients. Central carbon metabolism has an essential role in cellular function. In most cells is based on glucose, which is the primary energy source, provides the carbon skeleton for the biosynthesis of important cell macromolecules, and acts as a signaling molecule. The metabolic flux between pathways of carbon metabolism such as glycolysis, pentose phosphate pathway, and mitochondrial oxidative phosphorylation is dynamically adjusted by specific cellular economics responding to extracellular conditions and intracellular demands. Using Saccharomyces cerevisiae yeast cells and potentially similar fermentable carbon sources i.e. glucose and fructose we analyzed the parameters concerning the metabolic status of the cells and connected with them alteration in cell reproductive potential. Those parameters were related to the specific metabolic network: the hexose uptake - glycolysis and activity of the cAMP/PKA pathway - pentose phosphate pathway and biosynthetic capacities - the oxidative respiration and energy generation. The results showed that yeast cells growing in a fructose medium slightly increased metabolism redirection toward respiratory activity, which decreased pentose phosphate pathway activity and cellular biosynthetic capabilities. These differences between the fermentative metabolism of glucose and fructose, lead to long-term effects, manifested by changes in the maximum reproductive potential of cells.

Effect of Live and Fragmented Saccharomyces cerevisiae in the Feed of Pigs Challenged with Mycoplasma hyopneumoniae.

Currently, the responsible use of antimicrobials in pigs has allowed the continuous development of alternatives to these antimicrobials. In this study, we describe the impact of treatments with two probiotics, one based on live Saccharomyces cerevisiae (S. cerevisiae) and another based on fragmented S. cerevisiae (beta-glucans), that were administered to piglets at birth and at prechallenge with Mycoplasma hyopneumoniae. Thirty-two pigs were divided into four groups of eight animals each. The animals had free access to water and food. The groups were as follows: Group A, untreated negative control; Group B, inoculated by nebulization with M. hyopneumoniae positive control; Group C, first treated with disintegrated S. cerevisiae (disintegrated Sc) and inoculated by nebulization with M. hyopneumoniae; and Group D, treated with live S. cerevisiae yeast (live Sc) and inoculated by nebulization with M. hyopneumoniae. In a previous study, we found that on Days 1 and 21 of blood sampling, nine proinflammatory cytokines were secreted, and an increase in their secretion occurred for only five of them: TNF-α, INF-α, INF-γ, IL-10, and IL-12 p40. The results of the clinical evolution, the degree of pneumonic lesions, and the productive parameters of treated Groups C and D suggest that S. cerevisiae has an immunomodulatory effect in chronic proliferative M. hyopneumoniae pneumonia characterized by delayed hypersensitivity, which depends on the alteration or modulation of the respiratory immune response. The data presented in this study showed that S. cerevisiae contributed to the innate resistance of infected pigs.

Acetic Fermentation of Cagaita Pulp: Technological and Chemical Characteristics

The Brazilian Cerrado region has a rich plant diversity, with fruits that have peculiar and unique sensory characteristics. For these reasons, using these fruits for biotechnological production is a promising alternative, mainly to protect this biome from deforestation and degradation. The production of fermented acetic acid is an option to add value to native fruits and offer the market beverages with better nutritional quality and bioactive compounds. This work aimed to characterize fruits and to develop cagaita (Eugenia dysenterica DC.) acetic fermented beverage. The fruits were subjected to physical-chemical analyses in the first part. Subsequently, different treatments for fermentation were tested using two types of enzymes (amylase and pectinase), two subspecies of Saccharomyces cerevisiae yeast (UFLA CA11 and thermoresistant LNF Angel), and the chaptalization of the must with sucrose (16 °Brix). Alcoholic fermentation was carried out in an incubator with temperature control at 34 ± 1 °C. The pH, total soluble solids, titratable acidity, alcohol content, and density of the fermented products were monitored daily. The chaptalized must with amylase addition and thermoresistant yeast had the best performance during alcoholic fermentation, demonstrating that thermoresistant yeast is an economically advantageous and efficient alternative for the cagaita juice fermentation process. Subsequently, acetic fermentation was carried out using the slow method. Heat-resistant yeast without added enzymes was used to produce cagaita acetic fermented beverages within the parameters of the Brazilian legislation. Furthermore, phenolic compounds and antioxidant activity in the final product were observed. The work demonstrated the possibility of using cagaita fruits in biotechnological processes to produce new food products.

Synergistic Effect of a Combination of Proteasome and Ribonucleotide Reductase Inhibitors in a Biochemical Model of the Yeast Saccharomyces cerevisiae and a Glioblastoma Cell Line.

Proteasome inhibitors are used in the therapy of several cancers, and clinical trials are underway for their use in the treatment of glioblastoma (GBM). However, GBM becomes resistant to chemotherapy relatively rapidly. Recently, the overexpression of ribonucleotide reductase (RNR) genes was found to mediate therapy resistance in GBM. The use of combinations of chemotherapeutic agents is considered a promising direction in cancer therapy. The present work aimed to evaluate the efficacy of the combination of proteasome and RNR inhibitors in yeast and GBM cell models. We have shown that impaired proteasome function results in increased levels of RNR subunits and increased enzyme activity in yeast. Co-administration of the proteasome inhibitor bortezomib and the RNR inhibitor hydroxyurea was found to significantly reduce the growth rate of S. cerevisiae yeast. Accordingly, the combination of bortezomib and another RNR inhibitor gemcitabine reduced the survival of DBTRG-05MG compared to the HEK293 cell line. Thus, yeast can be used as a simple model to evaluate the efficacy of combinations of proteasome and RNR inhibitors.

The Role of the RPD3 Complex of Saccharomyces cerevisiae Yeast in the Activation of UV-Induced Expression of RNR Complex Genes

Reparative chromatin assembly is an important step in maintaining the stability of the genome. Proper chromatin assembly is provided by histone chaperones. Violation of the function of these proteins can lead to the development of various forms of cancer and to a number of hereditary diseases in humans. One of the key processes in the reparative assembly of chromatin is acetylation and deacetylation of histones, complexes NuB4 and RPD3. Results presented in this work demonstrate that inactivation of Rpd3 and Sin3 subunits of the RPD3 complex blocks super activation of RNR3 gene. The phenotypes of rpd3Δ and sin3Δ mutants differ due to different activation of Rad53 kinase in these mutants, which may be due to deacetylation of Rad53 by Rpd3 deacetylase. Our findings revealed that the contribution of deacetylation of Rad53 kinase makes a significant contribution to the regulation hyperactivation RNR complex after UV irradiation. In addition, this work provides indirect evidence that the Him1 protein may participate as a histone chaperone in chromatin repair assembly.

Foliar urea applications to apple trees increase yeast assimilable nitrogen, amino acids, and flavor volatiles in fruit and hard cider

Volatile compounds are a crucial component of hard apple (Malus ✕domestica Borkh.) cider aroma, flavor, and consequent marketability. Amino acids are used by Saccharomyces cerevisiae yeast in the production of volatiles and their precursors. This study hypothesized that foliar applications of nitrogen to apple trees would elevate the concentration of amino acids in the fruit, thus increasing the concentration of sensorially distinguishable aromatic volatiles in cider. In this experiment, urea foliar fertilizer was applied to ‘Ellis Bitter’ and ‘Harry Masters Jersey’ apple trees to create Control (0 applications), Low (3 weekly applications), and High (5 weekly applications) treatments. Total leaf nitrogen increased with the number of foliar urea applications, demonstrating plant uptake. The total fruit yield and fruit efficiency (total harvested fruit mass relative to trunk cross-sectional area) did not differ among treatments within the same cultivar. Similarly, fruit maturity, size, total phenolics, pH, and soluble solids concentration did not differ among treatments. Yeast assimilable nitrogen (YAN) and amino acids in the juice increased with the number of foliar urea applications, as did fermentation rates. Relative to the Control, the High treatment had 130% greater YAN in ‘Ellis Bitter’ and 145% in ‘Harry Masters Jersey’. Over 90% of the YAN in all juice samples was composed of primary amino nitrogen (PAN), and the majority of the PAN among all treatments was asparagine. Ester and fatty acid content in hard ciders increased with the number of urea applications; however, higher alcohols showed a mixed relationship with the number of applications in the cultivar ‘Ellis Bitter’. Aroma and flavor differences among treatments were discernible by triangle discrimination test panelists; however, the specific sensory differences were not easily identifiable with untrained panelists. This study demonstrated that late season foliar urea applications to apples trees can increase juice YAN and aromatic compounds in finished cider.

Sustainable energy enhancement strategy from Chlorella vulgaris microalgae biomass resource

ABSTRACT Growing demand for renewable and sustainable energy sources has prompted research into bioethanol production as a viable alternative to hydrocarbon fuel for automobile engines. Based on their high carbohydrate content, Chlorella vulgaris microalgae were chosen for this study as a feasible biomass for bioethanol synthesis. After conducting microwave-based acid hydrolysis with varying acid concentrations of sulfuric acid (H2SO4) for 1–15 min, this study found that 3% H2SO4 for 5 min yielded the highest yield of reducing sugar (6.77 g/L). In this work, the RSM approach of central composite design (CCD) was utilized for modeling and optimization of ethanol fermentation and the MATLAB Simulink approach was employed for the simulation of ethanol fermentation. This study compared the effects of using Saccharomyces cerevisiae yeast for fermentation at different fermentation times (12 to 48 h), temperatures (28 to 32°C), and size of inoculum (0.5–1.5 g/L). Based on the actual and predicted results, the best conditions for fermentation were 36 h of time, 30°C of temperature, and 1.5 g/L of inoculum size. This gave the maximum ethanol concentration of 3.31 g/L. Furthermore, the RSM method provides minimum error and maximum R2 value results for ethanol production compared to MATLAB simulation prediction (MSP). In addition, residue biomass from biofuel production is evaluated for its suitability for a further form of biofuel production. This research explores the opportunities for zero-waste biomass utilization in the development of biofuels.

Transcriptional Analysis of Mixed-Culture Fermentation of Lachancea thermotolerans and Saccharomyces cerevisiae for Natural Fruity Sour Beer

Increasingly high interest in yeast–yeast interactions in mixed-culture fermentation is seen along with beer consumers’ demands driving both market growth and requests for biotechnological solutions that can provide better sensory characteristics. In this study, Lachancea thermotolerans and Saccharomyces cerevisiae with a cell population ratio of 10:1 were inoculated for sour beer fermentation while the process conditions within the brewing industry remained unchanged. With L. thermotolerans producing lactic acid (1.5–1.8 g/L) and bringing down the pH to 3.3–3.4 whilst adding no foreign flavors herein, this study revealed a new natural, fruity sour beer with a soft, sour taste. In this study, the double-yeast mixed-culture fermentation produced more flavor substances than a single-culture process, and plenty of isobutyl acetate and isoamyl acetate enhanced the fruit aroma and balanced the sour beer with a refreshing taste. While playing a positive role in improving the beer’s quality, the double-yeast mixed-culture fermentation developed in this study helps to offer an alternative mass production solution for producing sour beer with the processes better controlled and the fermentation time reduced. The stress responses of the L. thermotolerans during the fermentation were revealed by integrating RNA sequencing (RNA-Seq) and metabolite data. Given that the metabolic flux distribution of the S. cerevisiae during the fermentation differed from that of the non-Saccharomyces yeasts, transcriptional analysis of non-Saccharomyces yeast and S. cerevisiae could be suitable in helping to develop strategies to modulate the transcriptional responses of specific genes that are associated with the aroma compounds released by S. cerevisiae and non-Saccharomyces yeasts. In the case of some non-Saccharomyces yeast species/strains, the diversion of alcoholic fermentation and the formation of a great number of secondary compounds may, in part, account for the low ethanol yield.

Residual brewer’s Saccharomyces cerevisiae yeasts as biofertilizers in horticultural seedlings: towards a sustainable industry and agriculture

The food industry generates substantial amounts of organic waste often underutilized within the system. Craft beer production, experiencing global rapid expansion, contributes to this waste stream with byproducts such as spent grain, trub, and yeast. Many craft beer industries discharge yeast residue directly into public water bodies. In recent years, yeasts have garnered attention for their potential to enhance plant growth and contribute to sustainable agriculture. This study focuses on characterizing Saccharomyces cerevisiae yeast collected at the end of the craft beer fermentation process. Biomass characterization was conducted, and the yeast’s effect on lettuce and tomato seeds and seedlings was evaluated at four concentrations (105, 106, 107, and 108 cells mL−1) in sterile substrate. After 28 days, plant height, leaf number, fresh and dry weights of both aboveground and root parts, as well as chlorophyll content, were analyzed. The most effective concentration (107 cells mL−1) was applied to tomato seedlings in sterile substrate, compared with a commercial organic fertilizer. After 21 days, growth parameters were assessed. The study demonstrated that increasing yeast doses up to 108 cells mL−1 positively affects seed germination and seedling development. Notably, a dose of 107 cells mL−1 proved effective for application in seedlings as an organic amendment and substitute for commercial products. This integrated approach showcases the potential of yeasts in sustainable agriculture, utilizing byproducts from the food industry to enhance crop performance and mitigate environmental pollution.

Kinetic Study of Fig Syrup Fermentation by Genetically Modified Saccharomyces cerevisiae Yeast Strains: A Physicochemical Approach to the Yeast Strain Life Cycle

Reversed-flow gas chromatography (R.F.G.C.) was employed to assess the impact of genetic modification on Saccharomyces cerevisiae yeast strains during the process of alcoholic fermentation, utilizing fig syrup. Multiple fermentations were carried out at various temperatures to evaluate the influence of genetic modifications on yeast strain efficiency. The study involved a wild-type yeast strain, W303, as a control and two genetically modified strains, W_M4_533 and W_M4_558, sharing the same genetic background as the wild type. Notably, the genetic modifications in the Msn4p transcription factor involved the substitution of serine residues with alanine at positions 533 and 558, resulting in the development of psychrophilic or ethanol-resistant strains. Utilizing the R.F.G.C. method enabled the differentiation of the duration of alcoholic fermentation phases, providing insights correlated to the yeast cell life cycle. The values of rate constants (k) for each phase, conducted with both wild-type and genetically modified cells using RFGC, aligned with the existing literature. Additionally, the calculation of activation energies for distinct phases revealed lower values for genetically modified strains compared to wild-type strains. This decrease in activation energies suggests enhanced efficiency in the alcoholic fermentation process for the genetically modified strains.

Fermentation Kinetic and Alpha-Amylase Inhibition Studies of Mao Wine Fermented by Three Commercial Saccharomyces cerevisiae Yeasts

Mao wine is produced from mao (Antidesma thwaitesianum) and is a local beverage promoting Sakon Nakhon province, Thailand. Understanding the fermentation process is necessary in order to enhance the quality of mao wine products. This study aims to examine the kinetics of mao wine fermentation using 3 commercial types of Saccharomyces cerevisiae yeasts, namely Lalvin 71B, Lalvin RC212 and Lalvin K1-V1116, with an initial pH of 3.4, a sweetness of 22 % Brix and a yeast concentration of 0.4 g L–1 in controlled conditions at 25 °C for 10 days. The results revealed that the kinetic models, including logistic, Luedeking-Piret and modified Luedeking-Piret equations, are appropriate for analyzing the kinetics of yeast growth, alcohol production and reducing sugar, respectively. Lalvin K1-V1116 yeast yielded the highest capacity for alcohol production (~113 g L–1), sugar-to-alcohol conversion (45 % conversion), and product efficiency (88 %), indicating its suitability for mao wine production. Furthermore, the investigation of the alpha-amylase inhibitory activity revealed that the IC50 values of mao wine samples were 2.88 - 4.78 mg mL–1, which were roughly 410 - 680 times greater than those of acarbose. These findings revealed the low efficacy of mao wine in inhibiting alpha-amylase activity. Nevertheless, a decrease in the level of inhibition may result in a decreased likelihood of side effects or undesirable reactions. This treatment is especially beneficial for people who have medication sensitivities. Additional research is required in order to substantiate its applicability in the management of type 2 diabetes. HIGHLIGHTS Mao wines were produced by 3 commercial cerevisiae yeast strains Lalvin K1-V1116 yeast exhibits the highest capacity in converting sugar to alcohol Lalvin K1-V1116 is the most suitable yeast for making mao wine The chosen kinetic models are appropriate for kinetic studies of fermentation process The efficacy of Mao wine in inhibiting the activity of alpha-amylase is quite low GRAPHICAL ABSTRACT

Adsorption of Zearalenone by Aureobasidium pullulans Autolyzed Biomass Preparation and Its Detoxification Properties in Cultures of Saccharomyces cerevisiae Yeast.

Different preventive strategies are needed to minimize the intake risks of mycotoxins, including zearalenone (ZEN). The aim of this study was to determine the ZEN adsorption ability of an autolyzed biomass preparation of polymorphic yeast Aureobasidium pullulans A.p.-3. The evaluation of the antitoxic properties of the preparation was also performed in relation to Saccharomyces cerevisiae yeast (ATCC 2366, ATCC 7090 and ATCC 9763) used as a model cell exposed to a toxic ZEN dose. The preparation at a dose of 5 mg/mL showed the adsorption of ZEN present in model systems at concentrations between 1 μg/mL to 100 μg/mL. The highest degree of adsorption was established for ZEN concentrations of 1 μg/mL and 5 μg/mL, becoming limited at higher doses of the toxin. Based on the Langmuir model of adsorption isotherms, the predicted maximum ZEN adsorption was approx. 190 µg/mL, regardless of pH. The growth of three strains of S. cerevisiae yeast cells in the medium with ZEN at concentrations within the range of 1.56 μg/mL-100 μg/mL was analyzed to determine the minimum inhibitory concentration. The growth of all tested strains was especially limited by high doses of ZEN, i.e., 50 and 100 μg/mL. The protective effect of the tested preparation was noted in relation to yeast cells exposed to toxic 100 μg/mL ZEN doses. The highest yeast cell growth (app. 36% percentage) was noted for a S. cerevisiae ATCC 9763 strain compared to the medium with ZEN but without preparation. More detailed tests determining the antitoxic mechanisms of the A. pullulans preparation are planned in the future, including cell culture bioassays and animal digestive tract models.

The Effect of Molasses Concentration on the Growth of Yeast Saccharomyces Cereviceae in Making Single Cell Proteins the Effect of the concentrate on of Waste Molasses on the Growth of Yeast Saccharomyces Cereviceae in the Making of Single Cell Proteins

The aim of the research was to determine the optimal molasses concentration for the growth of Saccharomyces Cereviciae yeast and the protein content of Saccharomyces cerevisiae yeast in making PST. This research used an experimental method with a quantitative approach and used a Completely Randomized Design (CRD) with 5 treatments and 3 replications. The concentrations in this study were 10%, 15%, 20%, 25% molasses and control. The results obtained showed that the protein levels obtained ranged from 13-47%. Apart from that, the highest specific growth rate (SGR) and protein productivity were found in the M1 treatment with 10% molasses.

Effect of Fermentation Conditions (Dilution Ratio, Medium pH, Total Soluble Solids, and Saccharomyces cerevisiae Yeast Ratio) on the Ability to Ferment Cider from Tamarillo (Solanum betaceum) Fruit

Tamarillo (Solanum betaceum) is a nutrition-rich product containing antioxidant components and preventive properties against cancer risk. However, there is currently a scarcity of research on processing techniques to diversify products and extend the preservation time of the active compounds in tamarillo. In this study, we focused on developing a cider processing procedure from tamarillo by fermentation with Saccharomyces cerevisiae (Angel RV002). Fermentation conditions, such as the dilution ratio (66 : 34–34 : 66%, w/w), medium pH (3.5–5), total soluble solids (TSS 10–26°Brix), and yeast ratio (0.6–1.2 g/L) were investigated. Ethanol concentration, pH, TSS, titratable acidity, total sugar content, and reducing sugar content were evaluated from day 0 to day 5 of fermentation. At a 50 : 50 (%, w/w) dilution ratio of the tamarillo juice with water, pH 4.5, TSS of 22°Brix, and the addition of yeast 0.6 g/L to the fermentation process, the ethanol concentration reached 7.54±0.11 (%, v/v) after 4 days of fermentation. Additionally, the product maintained a moderately low pH (pH 4.16). The final product exhibited a high sugar content and dissolved nutrients. The results of this study are expected to serve as a basis for the production of tamarillo cider, contributing to the diversification of the product, enhancing the value of tamarillo, and promoting economic development in the region of cultivation.

Effects of Live Saccharomyces cerevisiae Yeast Administration in Periparturient Dairy Cows

Dairy cows face several challenges during the transition period, and the administration of live yeast might be useful to mitigate this stressful condition. In the current study, the effects of live yeast administration on milk production, feed intake, and metabolic and inflammatory conditions were evaluated. Multiparous Holstein cows were enrolled in this randomized controlled trial and received either a control diet (CTR, n = 14) or the control diet plus 4 g/d of live Saccharomyces cerevisiae yeast (LSC, n = 14) from −21 to 56 days relative to calving. Dry matter intake, milk yield and composition, and rumination time were monitored daily. Blood samples were collected at −21, −7, 3, 14, 28, 42, and 56 days relative to calving to evaluate the metabolic profile. Fecal samples were collected at 56 days relative to calving to measure volatile fatty acids and feed digestibility. No differences between groups were observed in dry matter intake. Compared with CTR, rumination time was lower in LSC in after calving. Although there were no differences in milk components between groups, LSC had greater milk yield in the last three weeks of the study than CTR. No differences were observed in inflammatory markers or other plasma metabolites, except for β-hydroxybutyrate, which was higher in LSC, and reactive oxygen metabolites (ROMs), which were lower in LSC. Overall, these outcomes suggest that live yeast supplementation had some positive effects on milk yield and oxidative status.

Applications of diastatic Saccharomyces cerevisiae in brewing, distilling and biofuel production

Why was the work done: Diastatic variants of Saccharomyces cerevisiae are unusual in producing an extracellular glucoamylase which enables the breakdown of starch to fermentable sugars. Diastatic S. cerevisiae has long been viewed negatively as a contaminant of especially beer packaged in cans or bottles. However, this view is being reconsidered due to the opportunities that diastatic strains present for niche fermented products and distillation applications. What are the main findings: This review highlights the utilisation of diastatic S. cerevisiae for its flavour potential, and processing applications in the brewing, distilling, and biofuel industries. Further, genetic differences are compared with non-diastatic strains of S. cerevisiae, together with commonly employed and emerging methods of detection. Why is the work important: Diastatic yeast strains can be used to create flavour profiles that resemble traditional beverages and can be used to achieve fermentation with higher attenuation. This offers greater fermentation efficiency in, for example, the development of low-calorie beers. Additionally, the ability of diastatic strains of S. cerevisiae to convert non-fermentable oligosaccharides to fermentable sugars enables applications that range from novel beverages using unusual raw materials to more efficient distillation and biofuel production. The negative attributes that are associated with diastatic S. cerevisiae yeasts can be managed through co-inoculation or hybridisation with standard strains.

Translation variation across genetic backgrounds reveals a post-transcriptional buffering signature in yeast.

Gene expression is known to vary among individuals, and this variability can impact the phenotypic diversity observed in natural populations. While the transcriptome and proteome have been extensively studied, little is known about the translation process itself. Here, we therefore performed ribosome and transcriptomic profiling on a genetically and ecologically diverse set of natural isolates of the Saccharomyces cerevisiae yeast. Interestingly, we found that the Euclidean distances between each profile and the expression fold changes in each pairwise isolate comparison were higher at the transcriptomic level. This observation clearly indicates that the transcriptional variation observed in the different isolates is buffered through a phenomenon known as post-transcriptional buffering at the translation level. Furthermore, this phenomenon seemed to have a specific signature by preferentially affecting essential genes as well as genes involved in complex-forming proteins, and low transcribed genes. We also explored the translation of the S. cerevisiae pangenome and found that the accessory genes related to introgression events displayed similar transcription and translation levels as the core genome. By contrast, genes acquired through horizontal gene transfer events tended to be less efficiently translated. Together, our results highlight both the extent and signature of the post-transcriptional buffering.