Brewer's Yeast Research Articles

Mannoproteins from inactivated whole cells of baker's and brewer's yeasts as functional food ingredients: Isolation and optimization.

Because of the structural multiplicity of yeast mannoproteins, they have shown a great interest as food ingredients for a wide range of applications. The yields and the structural properties of mannoproteins varied depending on the isolation methods and their sources (baker's and brewer's Saccharomyces cerevisiae yeasts). Noncovalently bound mannoproteins (6.5kDa) with a mannan/protein ratio of 0.63 and 2.78 were recovered upon the heat treatment of brewer's and baker's yeasts, respectively, whereas sodium dodecyl sulfate treatment led mainly to the release of nonglycosylated proteins. The highest yield of mannoproteins was achieved upon the enzymatic isolation with Zymolyase® from Arthrobacter luteus. The recovered covalently bound mannoproteins were characterized by a higher mannan/protein ratio (13.1 to 42.7) and a wider molecular weight distribution (5 to 10kDa; 10 to 100kDa; 100 to 400kDa). Predictive models were developed to understand and modulate the effects of isolation parameters on yield, the mannoproteins content, and the mannan/protein ratio. The enzyme concentration was the most significant parameter affecting the yield, whereas the reaction time was the most significant parameter affecting mannan/protein ratio. Comparison of predicted and experimental values validated the established predicted models for the isolation of well-defined mannoproteins from yeast for targeted food applications. PRACTICAL APPLICATION: The increasing demand for clean label health-promoting foods has fueled the development of highly functional ingredients that offer both techno-functionalities and health-promoting properties. This study reveals the efficiency of whole inactivated yeasts as sources of mannoproteins. Given the dependence of the techno-functional and health-promoting properties of mannoproteins on their molecular properties, the investigation of the effects of the yeast sources and the type of isolation methods on the structural properties of mannoproteins would allow the modulation of their properties. Furthermore, the developed predictive models for the enzymatic process are expected to enhance the isolation efficiency of mannoproteins with well-defined structures.

Inactivation kinetics of beer spoilage bacteria (Lactobacillus brevis, Lactobacillus casei, and Pediococcus damnosus) during acid washing of brewing yeast

This work aimed to estimate the inactivation kinetic parameters of four potential beer spoilage bacteria (Lactobacillus brevis DSM 6235, Lactobacillus casei ATCC 334, Pediococcus damnosus DSM 20289 and Pediococcus damnosus ATCC 29358) inoculated in brewing yeast submitted to acid washing with purposes of yeast recycle. The experiments were conducted at 4 °C in solutions with pH 1.5, pH 2, and pH 3 adjusted employing 85% phosphoric acid. The acid washing treatment of brewing yeasts in the most common pH used (pH 2.0) demanded almost 50 min for the first decimal reduction (δ) of L. brevis DSM 6235. Sensible strains to acid washing such as P. damnosus DSM 20289 demanded almost 70 min for 4 log reductions to be achieved. On the other hand, pH reduction of the acid washing from 2.0 to 1.5 allowed 4 log reduction of L. brevis DSM 6235) to be obtained in less than 50 min, without ruining brewer's yeast viability. Acid washing in pH 1.5 is a viable method for the inactivation of bacterial contaminants of brewing yeasts. Recycling of brewing yeasts through this approach may contribute to a more sustainable and environmental-friendly industry.

A feeling for the (micro)organism? Yeastiness, organism agnosticism and whole genome synthesis

Synthetic biologists attempt to apply engineering principles to biological systems. This involves treating organisms as “chassis” – neutral frames into which synthetic constructs can be inserted, rather than living entities with distinctive features. Here we focus on a particularly charismatic organism – Saccharomyces cerevisiae (brewer's yeast) – and the attempt to make a synthetic version of its genome. We argue that the “personality” of the yeast and the affective relationship scientists (and others) have to it, challenges the “organism agnosticism” of synthetic biology. This leads us to ask whether synthetic biologists have straightforwardly exploitative relationships to the organisms they work on. We connect this “feeling for the (micro)organism” to the activity of engineering whole genomes, rather than discrete genetic parts. We argue that this connection is significant because we are likely to see an escalation in attempts to synthesize complete genomes in the future, including the human genome.

Assessing Population Diversity of Brettanomyces Yeast Species and Identification of Strains for Brewing Applications.

Brettanomyces yeasts have gained popularity in many sectors of the biotechnological industry, specifically in the field of beer production, but also in wine and ethanol production. Their unique properties enable Brettanomyces to outcompete conventional brewer’s yeast in industrially relevant traits such as production of ethanol and pleasant flavors. Recent advances in next-generation sequencing (NGS) and high-throughput screening techniques have facilitated large population studies allowing the selection of appropriate yeast strains with improved traits. In order to get a better understanding of Brettanomyces species and its potential for beer production, we sequenced the whole genome of 84 strains, which we make available to the scientific community and carried out several in vitro assays for brewing-relevant properties. The collection includes isolates from different substrates and geographical origin. Additionally, we have included two of the oldest Carlsberg Research Laboratory isolates. In this study, we reveal the phylogenetic pattern of Brettanomyces species by comparing the predicted proteomes of each strain. Furthermore, we show that the Brettanomyces collection is well described using similarity in genomic organization, and that there is a direct correlation between genomic background and phenotypic characteristics. Particularly, genomic patterns affecting flavor production, maltose assimilation, beta-glucosidase activity, and phenolic off-flavor (POF) production are reported. This knowledge yields new insights into Brettanomyces population survival strategies, artificial selection pressure, and loss of carbon assimilation traits. On a species-specific level, we have identified for the first time a POF negative Brettanomyces anomalus strain, without the main spoilage character of Brettanomyces species. This strain (CRL-90) has lost DaPAD1, making it incapable of converting ferulic acid to 4-ethylguaiacol (4-EG) and 4-ethylphenol (4-EP). This loss of function makes CRL-90 a good candidate for the production of characteristic Brettanomyces flavors in beverages, without the contaminant increase in POF. Overall, this study displays the potential of exploring Brettanomyces yeast species biodiversity to find strains with relevant properties applicable to the brewing industry.

Effect of spent brewer's yeast β-D-glucan on properties of wheat flour dough and bread during chilled storage

Effect of spent brewer's yeast β-D-glucan incorporation (0.25–2.00%, w/w wheat flour) on the characteristics of wheat flour dough and bread during chilled storage at 4 °C for 8 days was investigated. The dough containing 0.75% yeast β-D-glucan had the highest strength, work of adhesion, and stickiness. The addition of yeast β-D-glucan up to 0.75% yielded the breads with an appearance comparable to the control bread (without yeast β-D-glucan). The staling of bread was retarded by the addition of yeast β-D-glucan up to 0.75% as evidenced by the higher retained moisture content and cohesiveness and the lower L* value and hardness of the bread crumb during chilled storage compared to the control and the 1.00–2.00% yeast β-D-glucan breads. The 0.75% yeast β-D-glucan bread exhibited the lowest melting enthalpy of retrograded starch (ΔHret), the lowest B-type- and total crystallinities, the least microstructure change of the crumb matrix, and the highest consumer acceptance after 4 days chilled storage. These results suggested that the incorporation of an appropriate amount of yeast β-D-glucan could improve the quality and shelf life of bread or other starch-based food products during chilled storage.

Определение рациональных параметров акустической обработки с целью активации пивных дрожжей

В бродильных производствах, в частности, в пивоварении актуальными являются задачи повышения бродильной активности дрожжей и/или интенсификация накопления их биомассы. Для ее решения в настоящее время предлагаются различные способы, одним из которых может быть предварительная обработка волновыми или полевыми воздействиями. Ранее в наших исследованиях была показана принципиальная возможность интенсификации развития дрожжевых популяций за счет предварительной обработки звуком слышимого диапазона. Данная статья посвящена изучению влияния параметров акустической обработки на такие характеристики процесса культивирования дрожжей, как прирост общего титра клеток, доля нежизнеспособных клеток, убыль веса среды культивирования. Определяли эффективность обработки засевных дрожжей Saccharomyces cerevisiae (Saflager W34/70) звуком слышимого диапазона, варьируя следующие параметры акустического воздействия: частоту звука, продолжительность обработки, амплитуду, расстояние от источника звука до обрабатываемого объекта (навески сухих дрожжей). Обработанными и необработанными звуком дрожжами засевали модельные среды (стерилизованные 5 %-ные растворы сахарозы) и вели культивирование при комнатной температуре без принудительного перемешивания в течение 4 сут. Сразу после засева и ежедневно в процессе культивирования определяли контролируемые показатели. На основании полученных результатов был сделан вывод о том, что предварительная акустическая обработка, проведенная в рациональных условиях, позволяет увеличить прирост общего титра дрожжевых клеток и степень утилизации компонентов питательной среды при сохранении процента нежизнеспособных клеток на уровне контроля. Это создало предпосылки для апробации предлагаемого способа активации пивных дрожжей в условиях, приближенных к производственным.

Modeling the inactivation of Lactobacillus brevis DSM 6235 and retaining the viability of brewing pitching yeast submitted to acid and chlorine washing.

This study aimed to model the inactivation of Lactobacillus brevis DSM 6235 while retaining the viability of yeasts during washing brewer's yeast with phosphoric acid and chlorine dioxide. The independent variables in the acid washing were pH (1-3) and temperature (1-9°C), whereas in the washing with chlorine dioxide, concentration (10-90mg/L) and temperature (5-25°C) were assessed. The predictive models obtained for the four response variables γLA, γCl (decimal reduction of L. brevis DSM 6235), Vf/V0LA, and Vf/V0Cl (brewer's yeast viability ratio) were found to have R2 > 0.80 and values of Fcalc > Freference. Then, the models were considered predictive and statistically significant (p < 0.10). Our results indicated that phosphoric acid and chlorine dioxide washing resulted in up to 7 and 6.4 (log CFU/mL) decimal reductions of L. brevis DSM 6235, respectively. On the other hand, the viability of the brewer's yeast ranged from 22.3 to 99.4%. L. brevis DSM 6235 inactivation was significantly influenced by parameters pH(Q) and T°C(Q) when phosphoric acid was applied, and by parameters mg/L(L), mg/L(Q), T°C(Q), and mg/L × T°C when ClO2 was applied. The validation of the models resulted in bias (γLA, 0.93/Vf/V0LA, 0.99 - γCl, 1.0/Vf/V0Cl, 0.99) and accuracy values (γLA, 1.12/Vf/V0LA, 1.01 - γCl, 1.08/Vf/V0Cl, 1.03). The results of this study indicate that it might be possible to decontaminate brewer's yeast through acid and chlorine dioxide washing while keeping its viability. This procedure will result in the reduction of costs and the lower generation of brewer's waste.

Novel Assessment Method of the Critical Parameters for Brewing Yeast Formulation as a Nutraceutical in Animal Diets

Brewing yeast biomasses may be converted into valuable products, including supplements for ruminant diets. This paper presents experimental data on a nutraceutical suspension formulation containing post-fermentation brewing yeasts and the brewing yeast strain, Saccharomyces pastorianus ssp. carlsbergensis W34/70, which was intended to be administered to ruminants. The brewing yeast biomass is a component of oral suspensions designed as dietary supplements that prevent digestive acidosis in ruminants. The brewing yeast strain W34/70 was cultivated using molasses (M) and glucose (G) as carbon sources and was lyophilized at different freezing temperatures (0�C, �10�C, �20�C, �30�C, and �40�C). The post-fermentation brewing yeast biomass was spray dried (AAY) and lyophilized (ALY). Both dried yeast biomasses were analyzed in terms of wettability using a contact angle (CA�) evaluation at the solid/liquid interface. Suspensions were subsequently formulated and tested. Their physical and aggregative stability was established in connection with controlled sedimentation and flocculation. The assays were performed following quality by design (QbD) principles. The critical process parameters (CPPs) corresponding to the technological process of yeast production, as well as the critical quality attributes (CQAs) for suspension formulations, were pointed out as preamble determinants when designing oral nutraceuticals destined to be included in ruminant diets.

Behavioural responses of Tribolium castaneum (Herbst) to different types of uninfested and infested feed.

Tribolium castaneum is one of the most economically important insects that damages stored products. The effects of several infested or uninfested raw feed materials (wheat bran, coarse wheat meal, corn feed flour), feed products (compound feed for pigs and for laying hens) and flour mixed with brewer's yeast on the food-searching behaviour of T. castaneum adults were studied in a total of 48 combinations. Preference and olfactometer tests revealed that all the tested uninfested and intraspecific infested substrates were significantly more attractive to T. castaneum than the control (represented by part of an arena or olfactometer arm without substrate). We determined that all infested substrates were 2-9 times more attractive than uninfested in the preference test, while in the olfactometer test, they were 3-8 times more attractive. In comparing the attractiveness of the infested and uninfested substrates, in both tests wheat bran was found to be the most attractive substrate to T. castaneum adults and coarse wheat meal the least. The results of the present study contribute to our knowledge of how raw feed materials and products influence the behaviour of T. castaneum and their susceptibility to infestation, and indicate the possible utilization of wheat bran in monitoring processes of T. castaneum in pest management programmes.

Anti-inflammatory, Analgesic and Antipyretic Properties of Ethanolic Extracts of Three Plants of Beninese’s Pharmacopoeia: Euphorbia hirta, Citrus aurantifolia and Heterotis rotundifolia

Background/Objective: Euphorbia hirta, Citrus aurantifolia and Heterotis rotundifolia are commonly used in Benin in the treatment of infectious diseases. The aim of this study is to evaluate the anti-inflammatory, analgesic and antipyretic properties of ethanolic extracts of these plants.&#x0D; Materials and Methods: The study was carried out on 30 wistar rats placed in 6 work lots. A positive control lot having received diclofenac and a negative control lot having received physiological water were used. The ethanolic extract of the plants was used at a dose of 200 mg / kg bw. The model of inflammatory edema of the rat paw induced by 2% formalin was used. Analgesic activity was assessed by the pain method induced by 3% acetic acid and the tail immersion method with wistar rats. The antipyretic effect was evaluated on pyrexia induced by brewer's yeast at 20% with wistar rats.&#x0D; Results: After injection of formalin to animals, inflammatory reaction was almost immediate with appearance of classic signs of acute local inflammation (Redness, pain, heat and edema) at the five experimental groups. This inflammatory reaction occurs in two phases. The first phase occurs between 0 and 2 hours after injection of phlogogenic agent and the second phase, initiated after two hours extending to the fifth hour and even beyond. Administration of these extracts prevents edema inflammatory and inhibition percentages of edema vary between 23.67% and 86.76% for the three extracts. These extracts have similar anti-inflammatory activity (p&gt; 0.05) to that of diclofenac at 50 mg/kg. Analgesic activity show that these extracts inhibit very significantly (p&lt;0.001) chemical pain induced by acetic acid and the highest inhibition percentage is 60.34% (Citrus aurantifolia). This percentage is like to that of acetylsalicylic acid (67.35%) administered at the same dose. Likewise, these extracts attenuate significantly (p &lt;0.05) thermal pain induced by tail immersion of each rat in hot water at 50°C. Indeed, these extracts, reduces very significantly (p &lt;0.001) pyrexia induced by 20% beer yeast suspension in rats and they have similar effect (p&gt; 0.05) to that of acetylsalicylic acid at the fourth hour.&#x0D; Conclusion: These results show that the plants studied have the pharmacological properties evaluated. These results justify the use of these plants in traditional medicine.

Co-fermentation Involving Saccharomyces cerevisiae and Lactobacillus Species Tolerant to Brewing-Related Stress Factors for Controlled and Rapid Production of Sour Beer.

Increasing popularity of sour beer urges the development of novel solutions for controlled fermentations both for fast acidification and consistency in product flavor and quality. One possible approach is the use of Saccharomyces cerevisiae in co-fermentation with Lactobacillus species, which produce lactic acid as a major end-product of carbohydrate catabolism. The ability of lactobacilli to ferment beer is determined by their capacity to sustain brewing-related stresses, including hop iso-α acids, low pH and ethanol. Here, we evaluated the tolerance of Lactobacillus brevis BSO464 and Lactobacillus buchneri CD034 to beer conditions and different fermentation strategies as well as their use in the brewing process in mixed fermentation with a brewer’s yeast, S. cerevisiae US-05. Results were compared with those obtained with a commercial Lactobacillus plantarum (WildBrewTM Sour Pitch), a strain commonly used for kettle souring. In pure cultures, the three strains showed varying susceptibility to stresses, with L. brevis being the most resistant and L. plantarum displaying the lowest stress tolerance. When in co-fermentation with S. cerevisiae, both L. plantarum and L. brevis were able to generate sour beer in as little as 21 days, and their presence positively influenced the composition of flavor-active compounds. Both sour beers were sensorially different from each other and from a reference beer fermented by S. cerevisiae alone. While the beer produced with L. plantarum had an increased intensity in fruity odor and dried fruit odor, the L. brevis beer had a higher total flavor intensity, acidic taste and astringency. Remarkably, the beer generated with L. brevis was perceived as comparable to a commercial sour beer in multiple sensory attributes. Taken together, this study demonstrates the feasibility of using L. brevis BSO464 and L. plantarum in co-fermentation with S. cerevisiae for controlled sour beer production with shortened production time.

Physiological Effects of Some Pollen Substitutes Diets on Caged Honey Bee Workers (Apis mellifera L.)

Nutritional value of four proteinaceous diets and their physiological effects on honey bee workers were evaluated under laboratory conditions. The tested diets were as follows: diet 1 – date (Phoenix dactylifera L.) syrup, skimmed milk powder and dried brewer's yeast, diet 2 – Fenugreek (Trigonella foenum-graecum L.), Turmeric (Curcuma longa L.) powders and dried brewer's yeast, diet 3 – chickpea (Cicer arietinum L.) flour, wheat germ and dried brewer's yeast and diet 4 - soybean meal, skimmed milk powder and dried brewer's yeast, beside a control group (bee bread). Caged Carniolan honey bee workers were used in the experiments. The consumption rate, workers longevity, development degree of hypopharyngeal glands (HPG), and weight of rectal contents were determined. The greatest consumption rate was recorded for the control group while the lowest one was recorded for diet 4. Feeding bees on diet 3 gave the longest longevity (LT50= 27.0 days) among the tested diets and as a second rank after bees in the control group (LT50 = 29.0 days) while diet 4 showed the lowest longevity (LT50 =20.5 days). The highest HPG development degree (3.78) was recorded for 9 days old bees in the control group, followed by diet 3 (3.24) while the lowest degree (2.14) was to diet 4. The weight of rectal contents of honey bee workers was 13.43, 16.03 and 16.12 mg/bee/3 days for diet 3, diet 1 and diet 2, respectively, suggesting the suitability of these diets to bees. In light of this study, diet 3 and 2 have the best physiological effects for bees with good nutritional values.

Antipyretic and antitumor effects of a purified polysaccharide from aerial parts of Tetrastigma hemsleyanum

Ethnopharmacological relevanceTetrastigma hemsleyanum Diels et Gilg (Sanyeqing) is traditionally used as a folk medicine for the treatments of inflammation, high fever, hepatitis and cancer, and can improve the immune function of the patient. It belongs to the family of Vitaceae, and is mainly distributed in southeast China (Yunnan province) and can be found in India (Andaman Islands), Myanmar, Thailand, Vietnam, Malaysia and Indonesia in the valleys with 1100–1300 m above the sea level. Aim of the studyThe present study aimed to characterize the chemical properties of a purified polysaccharide extracted from the aerial part of Tetrastigma hemsleyanum (SYQP) and investigate its antipyretic and antitumor effects in mice models. Materials and methodsWater-soluble crude polysaccharides from the aerial parts of Tetrastigma hemsleyanum were extracted and fractionated by DEAE and gel permeation chromatography. Homogeneity, molecular weight, monosaccharide composition, and FTIR analysis were performed to characterize the SYQP. Antipyretic effect of SYQP was examined using Brewer's yeast induced hyperthermia test. Antitumor effect was investigated using H22 tumor bearing mice. The serum cytokines were determined to evaluated the biological activities of SYQP. ResultsSYQP was composed of galacturonic acid (GalA), glucose (Glc), mannose (Man), arabinose (Ara), galactose (Gal), and rhamnose (Rha) with a molar ratio of 11.3:7.1:2.5:1.0:0.9:0.5 and it had an average molecular weight of 66.2 kDa. The oral administration of SYQP at 200 and 400 mg/kg could markedly suppress the hyperthermia of mice induced by Brewer's yeast and decrease the production of cytokines especially prostaglandin E2 (PGE2) in the serum of mice. SYQP inhibited the growth of H22 tumor in mice with inhibitory rate of 39.9% at the administration dose of 200 mg/kg and increased the production of cytokines such as tumor necrosis factor-alpha (TNF-a) and interferon γ (IFN-γ). Experimental results showed that the preventive administration of SYQP before lipopolysaccharide (LPS) reduced the high cytokine levels such as IL-6, IL-10 and IFN-γ, indicating that SYQP might act as a competitor with LPS to interact with toll like receptor 4 (TLR4), which further regulated the secretion of cytokines. ConclusionThe anti-inflammatory and antitumor activities of SYQP might be related to its regulation of host immune function by controlling the secretion of cytokines.

Low Lactic Acid-Producing Strain of Lachancea thermotolerans as a New Starter for Beer Production.

Growing consumer interest in new beer flavors is contributing to the application of innovative materials and non-Saccharomyces yeast in brewing. The goal of this study was to test the impact of the low lactic acid-producing Lachancea thermotolerans MN477031 strain on the process of fermenting beer wort, with two different concentrations of bitter compounds, and on the quality of the beer produced. Qualify factors were broadly analyzed, including ethanol content, apparent degree of fermentation, sugars, organic acids, free amino nitrogen, glycerol, volatile compounds, ions and so on. It was proven that the L. thermotolerans MN477031 strain demonstrated a high capacity for rapid initiation of wort fermentation, and a tolerance to hop-derived compounds. As a result, the alcohol content in beer from this method of production was approximately 20% lower, while the content of the real extract was significantly higher in comparison to commercial Safbrew T-58. This strain stands out from many strains of L. thermotolerans due to the low lactic acid production and only marginal influence on pH decrease compared to Saccharomyces cerevisiae. Therefore, the potential of MN477031 in the production of different types of beer (not only sour) is very high. The composition of volatile compounds in L. thermotolerans beer differs—not only in terms of the use of the strain, but also in hop variety.

Biological parameters of adult of Chrysoperla externa (Hagen, 1861) (Neuroptera: Chrysopidae) fed on Asteraceae pollen under laboratory conditions

The objective of this study was to evaluate the biological parameters and the preference of Artemisia tridentata Nutt (Asteraceae) industrial pollen grains and beer yeast by Ch. externa adults for a more suitable diet for laboratory rearing. To conduct the experiment, 105 adults of newly emerged Ch. externa were used. They were placed in PVC cages (10.0 cm high x 10.0 cm in diameter), closed with PVC plastic film, each cage contained two females and one male (2: 1), and each cage was placed on a diet, being they are: Artemisia pollen (A. tridentata), artemisia + honey pollen (mixed), beer yeast, beer yeast + honey (mixed), water, honey, artemisia pollen + honey (separated). The diets 2 (artemisia pollen + mixed honey), 3 (brewer's yeast) and 4 (brewer's yeast + mixed honey) were shown to be statistically good diets at 5% confidence, according to the results analyzed for the parameters fecundity, oviposition, oviposition, mean number of eggs/day and viability of eggs. As the other diets 1 (artemisia pollen), 5 (water), 6 (honey) and 7 (artemisia pollen + separated honey) did not obtain statistically results, because they had means zero or close to zero, so these treatments are not feasible for a rearing of Ch. externa in the laboratory.

Supplementation of brewer’s yeast slurry improves the performance of dairy cattle

Brewer's yeast slurry is the by-product of the beer processing industry which includes live cells of Saccharomyces cerevisiae. It is rich in high-quality protein, vitamins and minerals essential for the growth and well-being of animals. Moreover, Saccharomyces cerevisiae improves the growth of beneficial microflora in the rumen of ruminant animals. Sri Lanka is importing a large amount of milk and milk products to fulfill the demand of consumers. Lack of high-quality feed is one of the major concerns which hinders the dairy production in the country. Therefore, the purpose of this study was to investigate the effects of supplementing brewer's yeast slurry on the performance of dairy cattle in large scale production. In this study, 120 lactating cows were selected and divided into two groups as control and treatment considering their production, breed, and stage of lactation. The complete study period was 77 days. In the first period, the treatment group was fed with brewer's yeast slurry for 32 days. In the second period, which included 26 days both treatment and control groups were not fed brewer's yeast slurry. In the third period, the treatment group was fed brewer's yeast slurry for 19 days. Milk samples were collected daily and milk weight, fat content and density were measured. According to the results, milk production was significantly higher in the treatment group. Furthermore, supplementation of brewer's yeast slurry has improved the total solids and fat content of the milk.

Supplementation of brewer's yeast slurry improves the performance of dairy cattle

Supplementation of brewer's yeast slurry improves the performance of dairy cattle

Dietary supplementation of autolysed yeast enhances growth, liver functionality and intestinal morphology in African catfish

A feeding trial was conducted to evaluate the potential of dietary supplementation of autolysed brewer's yeast (AY) on African catfish. The catfish (22.5 ± 1.15 g/fish, 20 fish 33 L/tank) were fed with either of diets (390 g/kg crude protein, 140 g/kg lipid) supplemented with 0, 3, 6 or 10 g/kg AY (n = 3). After 49 days of feeding, the final body weight and metabolic growth rate of the catfish fed 3 g/kg AY (3‐AY) diet were higher than those fed the control diet (p .05) in intestinal perimeter ratio. However, an elevated (p < .05) abundance of goblet cells and intraepithelial leucocytes were found in the intestine of catfish fed 3, 6 and 10 g/kg AY diets, with the highest level of abundance recorded in the mid‐intestine of the catfish fed 3‐AY diet. The results suggest that dietary 3 g/kg autolysed brewer's yeast supplementation improves growth performance of African catfish without deleterious effect on liver functionality and gut morphology.

Spent brewer's yeast as an ingredient on the elaboration of cookies

Several studies have been conducted to find ways to use the spent yeast from brewery due to their high nutritional content (e.g., proteins, vitamins and minerals). Therefore, this study aimed to characterize the spent yeast from brewery and add it to cookies as an ingredient to valorize the waste from beer production. Spent yeast in its natural and autolysed form were characterized by physical-chemical analysis. Subsequently, formulations of cookies were developed with autolysed biomass (10% and 20%). These cookies were under physical-chemical and microbiological analysis. Finally, the cookies were submitted to the evaluation of acceptability as well. Brewer’s yeast is a potential source of protein, resulting in cookies with less carbohydrate content. The cookies without biomass has better acceptability, therefore, it is necessary to improve the formulations with spent yeast. However, it was noticed that brewer’s yeast has potential for its application in food and, its use as an ingredient on food formulations can be a way to valorize the residue from beer production.

Cellular mechanism for the improvement of multiple stress tolerance in brewer's yeast by potassium ion supplementation

SummaryThe ethanol fermentation efficiency was affected by multiple stress tolerance of yeast during brewing and bioethanol industry. The effect of KCl on the multiple stress tolerance of yeast cells was examined. Results showed that KCl addition significantly enhanced the tolerance of yeast cells to osmotic and ethanol stress, which correlated with the decreased membrane permeability, the increased intracellular ergosterol and ATP content, and the improved activity of complex II and complex III in yeast cells. Biomass and viability of yeast cells under osmotic and ethanol stress were increased significantly by KCl addition. Supplementation of 4 and 10 g L−1 KCl exhibited the best promotion activity for yeast cells present in medium with 500 g L−1 sucrose and 10% (v v−1) ethanol, respectively. These results suggested that exogenous potassium addition might be an effective strategy to improve yeast tolerance and fermentation efficiency during industrial very‐high‐gravity (VHG) fermentation.