Brewer's Yeast Research Articles

Revaluation of Waste Yeast from Beer Production

Brewing yeast is an important waste product from beer production. The valorification of slurry yeast mainly consists of separation of vitamins and important nitrogen compounds. The hops compounds, one of the most important raw materials in beer technology are removed beforehand valorification. The prenylflavonoids compounds from hops are important bioactive compounds that can be revaluation with proper technology. Revaluation of prenylflavonoids from waste yeast into dietary supplement, identification and quantification of xanthohumol by HPLC method. Waste yeast from brewery pilot plant of USAMV Cluj Napoca it was dried by atomization and the powder was analyzed on xanthohumol content by HPLC method. For quantification a calibration curve it was used. The process of drying by atomisation lead to a powder product. It was used malt dextrin powder for stabilisation. The final product it was encapsulated. The xanthohumol content of powdered yeast it was 1.94 µg/ml. In conclusion the slurry yeast from beer production it is an important source of prenylflavonoids compounds.

Comparison of assimilation of fermentable sugars in wort by the immobilized yeast in alginate gel and the free yeast in high gravity brewing

In this work, the assimilation of different fermentable sugars by the immobilized yeast in alginate gel and the free yeast under high gravity brewing conditions was investigated and compared. Both immobilized and free yeast utilized glucose, fructose, sucrose and maltose in wort from the beginning of the fermentation. Maltotriose uptake of the fixed cells was also observed during the first hours of fermentation while the free cells only started assimilating maltotriose after the first 48 h. High osmotic pressure at the start of the fermentation changed cellular morphology and that could decelerate the maltotriose uptake of the free yeast.

Self-cloning brewing yeast: a new dimension in beverage production

Since the mid-1990s, biotechnology has advanced, and there has been an increased focus on using genetically modified yeast in the production of fermented beverages and the manufacturing of bioethanol. Yeast is the primary microorganism for fermented beverages such as beer, wine and sake. However, existing individual strains will not completely fulfill future demands for an efficient and high-quality fermentation. In this case, several research groups have been working on genetic modifications of yeast to create an up-to-date application. Genetically modified organisms (GMO) such as yeast, crops and plants in the food and beverage production are not desired by the consumer. A possible solution to overcome the consumer distaste of products labeled as containing GMO could be the application of self-cloning yeasts. Thus, connotated, the modification of the genome occurs without heterologous DNA. This review is an overview of current research regarding the use of self-cloning yeast in brewing, wine making, baked goods and sake production. The main focus of this paper concerns the possibilities of promoter usage and the construction of self-cloning yeast and the monitoring of self-cloning yeast.

Bio-assisted synthesis of mesoporous Li3V2(PO4)3 for high performance lithium-ion batteries

The mesoporous biocarbon coated Li3V2(PO4)3 (MBC-LVP) cathode material is synthesized by a biotemplate-assisted sol–gel reaction process using low-cost beer waste brewing yeasts (BWBYs) as both structural template and biocarbon source. The structure and electrochemical performances of MBC-LVP were investigated using Raman spectra, thermogravimetric measurements (TGA), adsorption–desorption isotherms and pore-size-distribution curves, X-ray diffraction (XRD), transmission electron microscope (TEM and HRTEM), and electrochemical methods. The results show that the MBC-LVP synthesized at 750°C has a hierarchical nanostructure, which consist of Li3V2(PO4)3 crystal nanoparticles and amorphous biocarbons network (11.5%) with hierarchical mesoporous structures (slit shape mesopores, open wormlike mesopores and plugged mesopores). This hierarchical nanostructure facilitates electron and lithium ion diffusion. The MBC-LVP electrode has high discharge capacity (about 205mAhg−1) at a current density of 0.2C in the voltage region of 3.0–4.8V and the diffusion coefficient of Li+-ions determined by CV and EIS is higher than those of olivine LiFePO4. We have revealed the formation mechanism of MBC-LVP, the possible lithium pathways in the MBC-LVP and established a relation between the structure and the ionic and electronic transport properties.

Effects of Nitrogen Composition on Fermentation Performance of Brewer's Yeast and the Absorption of Peptides with Different Molecular Weights

Four kinds of worts with different nitrogen compositions were used to examine their effects on fermentation performance of brewer's yeast. The absorption pattern of peptides with different molecular weights (Mw) in yeast cells during wort fermentation was also investigated. Results showed that both the nitrogen composition and level had significant impacts on the yeast biomass accumulation, ethanol production, and free amino nitrogen and sugars consumption rates. Worts supplemented with wheat gluten hydrolysates increased 11.5% of the biomass, 5.9% of fermentability, and 0.6% of ethanol content and decreased 25.6% of residual sugar content during wort fermentation. Moreover, yeast cells assimilated peptides with various Mw differently during fermentation. Peptides with Mw below 1 kDa decreased quickly, and the rate of assimilation was more than 50% at the end of fermentation, while those with Mw above 10 kDa almost could not be assimilated by yeast. All these results further indicated that the level and composition of wort nitrogen had significant impacts on the growth and fermentation performances of brewer's yeast, and peptides with Mw below 1 kDa were one of preferred nitrogen sources for brewer's yeast.

The growth behavior of the model eukaryotic yeast Saccharomyces cerevisiae in microgravity

Saccharomyces cerevisiae is an eukaryotic model organism that has been used for space biology research. Microgravity is a tool to study yeast mechanobiology by removing the gravitational force on the cells. Yeast cells possess mechanosensors that can sense mechanical forces. The cells transduce a mechanical stimulus into a specific cellular response by activating intracellular signaling pathways that can ultimately lead to an altered function. Microgravity is sensed by yeast cells as a stress condition and several mitogen-activated protein kinases (MAPK) signaling pathways are activated, including the cell wall integrity (CWI)/protein kinase C (PKC), the high osmolarity glycerol (HOG) and the target of rapamycin (TOR) pathways. One of the indicators of morphological changes is an increase at random bud scar profile. Microgravity influences on the growth rate of yeast cells have been observed. The colony growth rate of the agar invasive S. cerevisiae �1278b strain was reduced as well as its agar invasiveness. Post-flight growth experiments of a brewer's top yeast strain showed an increase in G2/M and a decrease in Sub-G1 cell population; an increased viability, a decreased lipid peroxidation level, increased glycogen content, and changes in carbohydrate metabolic enzyme activities were also observed. Using the S. cerevisiae BY4741 deletion collection, genes that provide a survival advantage in space, were identified in a batch growth experiment; no difference in growth rate was observed. Freeze-dried strains showed significant changes in the cell wall thickness. Spaceflight unique gene expression changes were observed in stress response element (STRE) genes with transcription regulation involving Sfp1 (which is involved in the TOR pathway) and Msn4. Some of the components of the ribosome biogenesis (which is under the control of Sfp1) as well as components of the proteasome were down regulated in microgravity. Recent results indicate that imposes a microgravity stress on the cells, which has the characteristics of an osmotic stress. Cellular energy is directed towards protective measures such as cell wall biosynthesis (CWI pathway activation) and the production of compounds (glycerol, trehalose) that increase the osmotolerancy (HOG pathway).

Physiological tests for yeast brewery cells immobilized on modified chamotte carrier

In this study yeast cell physiological activity was assessed on the basis of the in situ activity of two important enzymes, succinate dehydrogenase and pyruvate decarboxylase. FUN1 dye bioconversion and cellular ATP content were also taken as important indicators of yeast cell activity. The study was conducted on six brewing yeast strains, which were either free cells or immobilized on a chamotte carrier. The experimental data obtained indicate clearly that, in most cases, the immobilized cells showed lower enzyme activity than free cells from analogous cultures. Pyruvate decarboxylase activity in immobilized cells was higher than in planktonic cell populations only in the case of the Saccharomyces pastorianus 680 strain. However, in a comparative assessment of the fermentation process, conducted with the use of free and immobilized cells, much more favorable dynamics and carbon dioxide productivity were observed in immobilized cells, especially in the case of brewing lager yeast strains. This may explain the higher total cell density per volume unit of the fermented medium and the improved resistance of immobilized cells to environmental changes.

New perspectives in the treatment of hidradenitis suppurativa: Surgery and brewer's yeast–exclusion diet

Hidradenitis suppurativa (HS), or acne inversa, is a chronic inflammatory skin disease characterized by abscesses, fistulating sinus tracts, and scarring. The exact pathogenesis of this disease remains unclear. We present our experience with HS and a possible cause of the disease and offer a surgical and clinical treatment that allows for disease resolution. We studied 12 patients who presented with axillary and perineal fistulas and underwent surgical excision (repaired by skin grafts or healing by secondary intention) or localized treatments followed by diet modification. All patients were found to have a specific immunology IgG reaction to brewer's yeast and wheat and were put on a controlled brewer's yeast-free diet for 12 months and followed monthly. The diet demonstrated immediate stabilization of their clinical symptoms, and the skin lesions regressed over the 12-month treatment period. Similarly, all the patients demonstrated an immediate recurrence of skin lesions following accidental or voluntary consumption of beer or other foods containing brewer's yeast or wheat. The patients also demonstrated a return of their quality of life and activities, including the reestablishment of sexual activity in the patients with inguinal and perigenital lesions. The results of the investigation suggested that the patients had severe reactions to brewer's yeast. Surgery followed by the elimination of the foods containing or made with the yeast resulted in a rapid stabilization of the dermatologic manifestation and a slow, but complete, regression of the skin lesions within a year. Despite the small number of patients in our study, our study could provide the basis for extensive and multicentric studies in order to better investigate this disabling and rare disease.

Preparation and characteristics of beta-glucan concentrate from brewer's yeast as the additive substance in foods

The brewer¢s yeast was used for preparation of concentrate with content of β-glucan. Hot water extraction (100°C, 5 hours) and subsequently an alkaline extraction of sediment using 1 M NaOH at 90°C for 1 hour were used. β-glucan concentrate containing 59,15 % of β-glucan had good functional properties (water binding capacity 13,34 g water/1 g concentrate, fat binding capacity 6,86 g fat/1 g concentrate) and indicated biological action too. At concentration of 2 mg/ml DMSO (dimethylsulfoxid) was viability of murine L1210 leukemic cells reduced to 76.15 %. When observing the antioxidant activity it was identified, that the lipid peroxidation in linoleic acid samples was decreased during the presence of β-glucan concentrate. These results and good sensory properties like a bright colour and the pleasant taste and smell indicate, that prepared β-glucan concentrate has a potential to be used to improve the health – beneficial substances in the foods.

Relationship between ethanol and oxidative stress in laboratory and brewing yeast strains

Ethanol is a chemical stress factor that inhibits cellular growth and determines metabolic changes leading to reduction of cell viability during fermentation and yeast storage. To determine the effect of time, temperature and ethanol during storage of brewing yeasts we have monitored viability of cells stored for 72 h, at 6 °C or 12 °C, in the presence of various ethanol concentrations. Under the conditions tested, 6 °C is the most favourable temperature to store brewing yeast creams emphasizing the importance of a tight temperature control in the storage vessels. Because W210 is less resistant to storage in the presence of ethanol than W34/70, the optimal storage parameters obtained under our laboratory conditions vary significantly. The ale strain is sensitive to storage under ethanol concentrations higher than 5% (v/v) for more than 48 h at 6 °C whereas at the same temperature the lager strain tolerates ethanol up to 7.5% (v/v) for 72 h. Also, the viability assays indicate that the antioxidant protein Yap1 is an important factor to storage resistance of BY4741 laboratory strain. To investigate the molecular mechanisms underlying tolerance of brewing yeast strains to ethanol, we have performed phenotypic analysis, localization studies and have monitored the activation of antioxidant and protection genes as well as the intracellular contents of glycogen and trehalose. Overall, our data suggest that the ale strain W210 has a defective antioxidant defence system and that ethanol may induce the antioxidant defences as well as glycogen and trehalose protection mechanisms in laboratory and brewing yeast strains.

Extreme resistance to weak-acid preservatives in the spoilage yeast Zygosaccharomyces bailii

Weak-acid preservatives, such as sorbic acid and acetic acid, are used in many low pH foods to prevent spoilage by fungi. The spoilage yeast Zygosaccharomyces bailii is notorious for its extreme resistance to preservatives and ability to grow in excess of legally-permitted concentrations of preservatives. Extreme resistance was confirmed in 38 strains of Z. bailii to several weak-acid preservatives. Using the brewing yeast Saccharomyces cerevisiae as a control, tests showed that Z. bailii was ~3-fold more resistant to a variety of weak-acids but was not more resistant to alcohols, aldehydes, esters, ethers, ketones, or hydrophilic chelating acids. The weak acids were chemically very diverse in structure, making it improbable that the universal resistance was caused by degradation or metabolism. Examination of Z. bailii cell populations showed that extreme resistance to sorbic acid, benzoic acid and acetic acid was limited to a few cells within the population, numbers decreasing with concentration of weak acid to <1 in 1000. Re-inoculation of resistant sub-populations into weak-acid-containing media showed that all cells now possessed extreme resistance. Resistant sub-populations grown in any weak-acid preservative also showed ~100% cross-resistance to other weak-acid preservatives. Tests using 14C-acetic acid showed that weak-acid accumulation was much lower in the resistant sub-populations. Acid accumulation is caused by acid dissociation in the higher pH of the cytoplasm. Tests on intracellular pH (pHi) in the resistant sub-population showed that the pH was much lower, ~ pH5.6, than in the sensitive bulk population. The hypothesis is proposed that extreme resistance to weak-acid preservatives in Z. bailii is due to population heterogeneity, with a small proportion of cells having a lower intracellular pH. This reduces the level of accumulation of any weak acid in the cytoplasm, thus conferring resistance to all weak acids, but not to other inhibitors.

Incidence and Characterization of Petites Isolated from Lager Brewing Yeast Saccharomyces cerevisiae Populations

Repeated reuse or “serial repitching” of yeast between successive fermentations exposes brewing yeast cells to a number of biological, chemical, and physical stresses. It is generally accepted that...

Impact of Storage Temperature on Lager Brewing Yeast Viability, Glycogen, Trehalose, and Fatty Acid Content

Impact of Storage Temperature on Lager Brewing Yeast Viability, Glycogen, Trehalose, and Fatty Acid Content

Effect of Carboxymethyl Cellulose and Alginate Coating Combined with Brewer Yeast on Postharvest Grape Preservation

The effect of carboxymethyl cellulose and alginate coating combined with brewer yeast on postharvest grape preservation was investigated. The postharvest grapes were coated with 2% of alginate and 3% of carboxymethyl cellulose combined with1.5×109 CFU/mL of brewer yeast. The combined treatment samples showed good sensory character on day 13 compared with control samples or only coated samples. The increase of weight loss and decrease of total soluble solids of combined treatment grapes were restrained. Furthermore, the protective enzymes including superoxide dismutase, peroxidase, and catalase of combined treatment sample showed higher activities. Accordingly, the increase of malonaldehyde content was also restrained and more vitamin C was preserved in combined treatment samples. At day 13, the weight loss rate and the total soluble solids of grape treated with coating + yeast were 23.6% lower and 20.6% higher than those of control samples, respectively. Coating grapes with 2% of alginate and 3% of carboxymethyl cellulose combined with brewer yeast of1.5×109 CFU/mL was a well-proven method to preserve postharvest grapes.

Transcription ofα-glucoside transport and metabolism genes in the hybrid brewing yeastSaccharomyces pastorianuswith respect to gene provenance and fermentation temperature

The hybrid lager yeast Saccharomyces pastorianus (S. cerevisiae × S. eubayanus) contains several genes encoding proteins responsible for the uptake and metabolism of maltose and maltotriose. In many cases the genes occur as orthologues, that is, the S. cerevisiae gene exists along with the S. eubayanus gene. Prior to formation of the hybrid, these genes existed in organisms, which had been separated for tens of millions of years and were expected to show some level of genetic and functional differentiation. In this study, oligonucleotide probes were designed for TRAC analysis of transcription of the S. cerevisiae and S. eubayanus orthologues of AGT1, MALx1, MALx2 and MALx3 as well as the S. cerevisiae-derived MPH2/3 genes within the S. pastorianus genome. Specificity of probes was validated using mRNA from S. cerevisiae and from S. eubayanus. Probes were used to analyse gene expression during 15°P wort fermentations conducted at different temperatures (10–20°C). As well as differential expression of different genes, differential expression of orthologues was also observed during fermentation. The differences suggest that, where two forms of the gene exist, either one will dominate (as with AGT1) or expression will be staggered (MALx2), possibly to maximize transport and for efficient degradation of sugars. Copyright © 2013 The Institute of Brewing & Distilling.

Digestibility and bioavailability of phosphorus from spray-dried yeasts in the diet of starting pigs (15-30 kg)

Two experiments were carried out to determine the bioavailability of phosphorus in two spray-dried yeasts - sugarcane yeast (SCY), and sugarcane yeast + brewer's yeast (SCBY) - in starting pigs, by comparing different methods (Apparent Digestibility Coefficient of Phosphorus - ADCP; True Digestibility Coefficient of Phosphorus - TDCP; slope ratio; and standard curve). In experiment I, a digestibility assay were carried out using 30 cross breed pig with initial weigh of 22.69 ± 4.24kg, allotted in a completely randomized design. The mean ADCP and TDCP values were 62.68 and 64.15% for SCY and 77.01 and 79.33% for SCBY. ADCP and TDCP for SCBY were higher (P&lt;0.05) than the values for SCY. In Experiment II, a growth test was conducted, 56 crossbred piglets, were utilized, with initial live weight of 15.11 ± 3.43kg, allotted in a completely randomized design, with seven treatments, four replications, and two pigs per experimental unit. The treatments consisted of a basal diet without supplementation with P and the same diet including supplementation with two levels of P (0.053% and 0.105%) from dicalcium phosphate, SCY and SCBY. The relative bioavailability mean value of 57.23% for SCY and 91.96% for SCBY, corresponding to 0.30% and 0.40% of available phosphorus, respectively.

Improving the biocontrol potential of entomopathogenic nematodes against Mamestra brassicae : effect of spray application technique, adjuvants and an attractant

Steinernema carpocapsae Weiser, an entomopathogenic nematode (EPN), is a potential biological control agent for the cabbage moth (Mamestra brassicae L.). This research aimed to identify a suitable spray application technique, and to determine whether yeast extract added to an EPN spray has an attracting and/or a feeding stimulant effect on M. brassicae. The biological control capabilities of EPN against this pest were examined in the field. Good coverage of the underside of cauliflower leaves, the habitat of young instar larvae (L1-L4) of M. brassicae was obtained using different spray boom configurations with vertical extensions that carried underleaf spraying nozzles. One of the configurations was selected for field testing with an EPN spray. Brewer's yeast extract stimulated larval feeding on leaves, and increased the mortality of these larvae when exposed to EPN. The field trial showed that a spray application with S. carpocapsae, Addit and xanthan gum can effectively lower the numbers of cabbage heads damaged by M. brassicae. Brewer's yeast extract did not significantly increase this field performance of EPN. Steinernema carpocapsae, applied with an appropriate spray technique, can be used within biological control schemes as part of a resistance management programme for Bt.

Brewer's Yeast as a New Source of Palmitoleic Acid—Analysis of Triacylglycerols by LC–MS

AbstractWe identified both fatty acids and TAG in waste yeast from seven breweries employing both top and bottom fermentation. Brewer′s yeast was found to contain FA exhibiting a broad range of acyl chain lengths, with a high proportion of the nutritionally and biotechnologically important palmitoleic acid. Analysis of FA by GC–MS and of TAG by LC–MS with APCI provided information on the type of brewer′s yeast and technology of fermentation. The composition of TAG containing major FA such as palmitic, palmitoleic and oleic acid was found to depend not only on the type of yeast strain, i.e. Saccharomycespastorianus or S. cerevisiae, but also on brewing fermentation process, i.e. top versus bottom fermentation. Top and bottom yeast can readily be distinguished by the ratios of some regioisomers of TAG since, e.g., the ratio of regioisomers PoOPo and PoPoO is always &gt;1 in top fermenting yeast and &lt;1 in bottom yeast. The ratios can thus be used as markers for determining the yeast type and beer‐producing technology in a given brewery.

Physiological state of reused brewing yeast

In brewing, yeast may be reused many times. A number of yeast repitchings differs significantly among the breweries. Adjusting the number of times a strain may be serially repitched is of great importance for quality and consistency of final products. The fermentative and physiological characteristics of the yeast culture used in successive laboratory scale fermentations were determined. Yeast physiological state was assessed by the measurement of the levels of intracellular carbohydrates. In our investigation there were not any detectable changes in yeast capacity to ferment. No significant variation in the production of flavour compounds was found either. However, intracellular glycogen and trehalose contents were dependant on the yeast strain, generation number and wort gravity. Nevertheless, an alteration in the yeast physiological condition during serial repitchings occurred in a different mode than in previous studies confirming that the impact of serial repitchings is strain and medium dependent to a large extent. &amp;nbsp;

Quality of royal jelly produced by Africanized honeybees fed a supplemented diet

This study was carried out to evaluate the effect of artificial supplements prepared with soybean protein isolate, brewer's yeast, mixture of soybean protein isolate with brewer's yeast, linseed oil, palm oil, and a mixture of linseed oil with palm oil on the physicochemical and microbiological composition of royal jelly produced by Africanized honey bee colonies. Considering these results, providing supplements for Africanized honeybee colonies subjected to royal jelly production can help and strengthen the technological development of the Brazilian beekeeping industry increasing its consumption in the national market. This research presents values of royal jelly a little different from those established by the Brazilian legislation. This fact shows that is important to discuss or change the official method for royal jelly analysis. The characterization of physicochemical and microbiological parameters is important in order to standardize fresh, frozen, and lyophilized royal jelly produced by Africanized honeybees.