Brewer's Yeast Research Articles

Silver triangular nanoplates as a colorimetric probe for sensing thiols: Characterization in the interaction with structurally related thiols of different functionality

Silver triangular nanoplates (AgTNPs) is a promising and still relatively poorly studied colorimetric probe for sensing various organic compounds. In particular, they undergo aggregation in presence of thiols due to strong interaction with SH-group. We performed characterization of label-free AgTNPs as a colorimetric probe in their interaction with thiols of different functionality. Aggregation of AgTNPs upon the action of thiols is manifested by a decrease of AgTNPs surface plasmon resonance (SPR) band and appearance of SPR band of AgTNPs aggregates in a long-wave region of a spectrum (700–800 nm). It can be used for sensitive spectrophotometric determination of thiols. Four thiols differing in their functional groups were tested. Limits of thiol detection in the selected optimal conditions increase in the series cysteamine < 2-mercaptoethanol < cysteine < 3-mercaptopropionic acid and come to 2, 3, 6, and 9 μg L−1, respectively. Selectivity of the method was evaluated by the example of cysteine. It was found that the determination does not interfere with 1000-fold amounts of inorganic ions and 3000-fold amounts of aminoacids. The method was applied to the determination of cysteine in a drug, brewer's yeast and a biologically active food supplement.

Survival of probiotic strain Lactobacillus paracasei L26 during co-fermentation with S. cerevisiae for the development of a novel beer beverage

Amidst the rising popularity of craft beers, it would be opportune to develop a novel, unfiltered and unpasteurized sour beer with high probiotic live counts. However, as beer typically contains hop iso-α-acids that prevent the growth and survival of probiotic lactic acid bacteria, the use of suitable fermentation strategies is crucial. The growth, and survival of the probiotic bacterium, Lactobacillus paracasei L26, were assessed during a 10-day co-fermentation period with a brewer's yeast, Saccharomyces cerevisiae S-04, in unhopped wort. Isomerized hop extract was added prior to storage of the beers at 25 °C and 5 °C. During co-fermentation in unhopped wort, L. paracasei L26 maintained high viable cell counts above 8 Log CFU/mL, indicating species compatibility with the yeast. The majority of fermentable sugars were attenuated by S. cerevisiae S-04, with a concomitant production of alcohols and esters. Significant amounts of lactic acid were produced by L. paracasei L26 (P < 0.05). During storage with added isomerized hop extract, maximal probiotic viability enhancing effects were observed in the presence of live S. cerevisiae S-04, in combination with refrigeration. The results suggest that beers could be a vehicle for probiotic delivery under appropriate conditions. This was the first study demonstrating the feasibility of utilizing probiotic lactobacilli as starter cultures in beer brewing.

Laboratory Evolution of a Saccharomyces cerevisiae × S. eubayanus Hybrid Under Simulated Lager-Brewing Conditions.

Saccharomyces pastorianus lager-brewing yeasts are domesticated hybrids of S. cerevisiae x S. eubayanus that display extensive inter-strain chromosome copy number variation and chromosomal recombinations. It is unclear to what extent such genome rearrangements are intrinsic to the domestication of hybrid brewing yeasts and whether they contribute to their industrial performance. Here, an allodiploid laboratory hybrid of S. cerevisiae and S. eubayanus was evolved for up to 418 generations on wort under simulated lager-brewing conditions in six independent sequential batch bioreactors. Characterization of 55 single-cell isolates from the evolved cultures showed large phenotypic diversity and whole-genome sequencing revealed a large array of mutations. Frequent loss of heterozygosity involved diverse, strain-specific chromosomal translocations, which differed from those observed in domesticated, aneuploid S. pastorianus brewing strains. In contrast to the extensive aneuploidy of domesticated S. pastorianus strains, the evolved isolates only showed limited (segmental) aneuploidy. Specific mutations could be linked to calcium-dependent flocculation, loss of maltotriose utilization and loss of mitochondrial activity, three industrially relevant traits that also occur in domesticated S. pastorianus strains. This study indicates that fast acquisition of extensive aneuploidy is not required for genetic adaptation of S. cerevisiae × S. eubayanus hybrids to brewing environments. In addition, this work demonstrates that, consistent with the diversity of brewing strains for maltotriose utilization, domestication under brewing conditions can result in loss of this industrially relevant trait. These observations have important implications for the design of strategies to improve industrial performance of novel laboratory-made hybrids.

Construction of industrial brewing yeast for fermentation under high temperature and high gravity condition

As a new beer fermentation technology, high temperature and high gravity fermentation has brought many benefits to brewery industry, but there are also a series of problems such as the decrease of yeast flocculation ability at the end of fermentation and the high concentration of higher alcohols. To increase yeast flocculation ability and reduce the production of higher alcohols in high temperature and high gravity fermentation of beer, BAT2 was replaced by the FLO5 expression cassette to obtain the mutant strain S6-BF2. Real-time quantitative PCR showed that the relative transcriptional level of FLO5 in S6-BF2 improved 17.8 times compared with that in S6. The flocculation ability of mutant S6-BF2 heightened by 63% compared to that of the original strain S6, and the concentration of higher alcohols decreased from 175.58 mg/L to 159.58 mg/L in high temperature and high gravity fermentation of beer. Moreover, the activity of mitochondrial branched-chain amino acid transferase was repressed, resulting in the production of higher alcohols of 142.13 mg/L, reduced by 18.4% compared to that of the original strain S6, meanwhile, the flocculation ability of mutant S6-BF2B1 kept unchanged compared to the mutant S6-BF2. The determination result of flavor compounds showed that the higher alcohols/ester ratio in beer was reasonable. This research has suggested an effective strategy for enhancing yeast flocculation ability and decreasing production of higher alcohols in high-temperature and high-gravity brewing.

Efficient fermentation of very high-gravity worts by brewer's yeast with wheat gluten hydrolysates and their ultrafiltration fractions supplementations

Very high-gravity (VHG) worts (24 °P) supplemented with wheat gluten hydrolysates (WGH) and their ultrafiltration fractions (Mw > 1 kDa and <1 kDa fractions) were used to evaluate their effects on physiological activity and ethanol fermentation of brewer's yeast. The results demonstrated that WGH and their ultrafiltration fractions supplementations could obviously improve the biomass and viability of yeast, and further enhance the sugar utilization and ethanol production under VHG fermentation. Supplementation with Mw < 1 kDa fraction exhibited the maximum biomass (6.90 g/L dry cell), sugar utilization (79.79%) and ethanol concentration (11.88%, v/v) during VHG fermentation. Meanwhile, the addition of Mw < 1 kDa fraction significantly decreased the plasma membrane permeability and intracellular reactive oxygen species (ROS) accumulation, and increased the mitochondrial membrane potential in cells during VHG fermentation. Moreover, Mw < 1 kDa fraction supplementation caused the highest accumulations of intracellular trehalose and glycerol, which were 12.10% and 31.22% higher than the control, respectively. These results illustrated that WGH (especially Mw < 1 kDa fraction) addition was an economic and efficient method to improve physiological activity and ethanol fermentation of brewer's yeast in VHG worts.

Utilization of brewing and malting by-products as carrier and raw materials in l-(+)-lactic acid production and feed application.

Application of agro-industrial by-products for the production of lactic acid was studied in this paper. Brewer's spent grain (BSG), malt rootlets (MR), brewer's yeast (BY), and soy lecithin (SL) were used as raw materials in L-(+)-LA fermentation by free and immobilized Lactobacillus rhamnosus ATCC 7469. The BSG, solid remains after BSG and MR hydrolysis (BSGMRSR), and MR were evaluated as carriers for batch and repeated batch fermentations with immobilized cells. During batch fermentations with immobilized cells, high cell viability (10 to 11logCFU/g) was achieved on all carriers. In batch fermentation with BSG as a carrier, the highest LA yield of 93.79% and volumetric productivity of 1.15g/L/h were obtained. Furthermore, very high LA yield (95.46%), volumetric productivity (1.98g/L/h) and L. rhamnosus viability (11.5logCFU/g) were achieved in repeated batch fermentations with the cells immobilized on this carrier. The immobilized cells showed high survival rate (94-95%) during exposure to simulated gut condition. Based on the analysis of BSGMRSR, and BY solid remains, and on in vitro evaluation of the probiotic characteristics of immobilized cells, it was observed that they could satisfy the recommendations for high-quality feed preparation.

Effect of supplementation with brewer's yeast hydrolysate on growth performance, nutrients digestibility, blood profiles and meat quality in growing to finishing pigs.

ObjectiveThis study was aimed to investigate the effects of brewer’s yeast hydrolysate (YH) on growth performance, nutrients digestibility, blood profiles and meat quality of growing pigs.MethodsA total of 200 growing pigs ([Landrace×Yorkshire]×Duroc) (initial body weight, 25.31±1.29 kg) were allotted to 5 treatments as follow: CON, basic diet; and YH treatment, CON+0.05%, 0.1%, 0.5%, and 1.0% of YH, respectively.ResultsOn wk 11, 16 and overall phase, pigs fed YH diet showed a linear improvement in average daily body gain and gain/feed (p<0.05). The pigs that received YH linearly increased the digestibility of dry matter, nitrogen, and energy on wk 11 and 16. The concentration of serum urea nitrogen was linearly increased in YH treatments on wk 16. However, the carcass weight, back fat and lean muscle percentage of pigs receiving YH had no significant change. Besides, no difference was observed in creatinine and total protein in the blood among treatments.ConclusionThe pigs fed a graded YH diet had improved growth performance and nutrient digestibility, meanwhile, the YH increased the serum urea nitrogen in the growing pigs.

Bioprospecting for brewers: Exploiting natural diversity for naturally diverse beers.

The burgeoning interest in archaic, traditional, and novel beer styles has coincided with a growing appreciation of the role of yeasts in determining beer character as well as a better understanding of the ecology and biogeography of yeasts. Multiple studies in recent years have highlighted the potential of wild Saccharomyces and non-Saccharomyces yeasts for production of beers with novel flavour profiles and other desirable properties. Yeasts isolated from spontaneously fermented beers as well as from other food systems (wine, bread, and kombucha) have shown promise for brewing application, and there is evidence that such cross-system transfers have occurred naturally in the past. We review here the available literature pertaining to the use of nonconventional yeasts in brewing, with a focus on the origins of these yeasts, including methods of isolation. Practical aspects of utilizing nondomesticated yeasts are discussed, and modern methods to facilitate discovery of yeasts with brewing potential are highlighted.

Use of high‐protein brewer’s yeast products in practical diets for the Pacific white shrimp Litopenaeus vannamei

Two 6-week growth trials and a digestibility trial were conducted to evaluate the effects of brewer's yeast in practical shrimp feeds. In the first growth trial, graded levels (0, 60, 120, 180 and 240 g/kg) of a brewer's yeast (BY50) were used to replace fishmeal and soybean meal, referred to as Diet DBY0, DBY6, DBY12, DBY18, DBY24 and Diet LFM0, LFM6, LFM12, DBY18 and LFM24, respectively. The results showed that there were no significant differences in final biomass, survival, protein retention efficiency and feed conversion ratio; however, limited differences in final weight and weight gain were shown in the FM replacement series. There was no significant difference on the growth performance in the SBM replacement series. The second growth trial was conducted with Diet DBY0, DBY12, DBY18, DBY24, LFM0 and a low-FM diet containing 20 g/kg of BY with 700g/kg (?) protein (Diet DBY70). Shrimp fed with Diet DBY0 exhibited significantly higher final mean weight and weight gain than those offered the Diet DBY24. Nutrient availability of BY50 and BY70 was similar to SBM and significantly higher than FM. Results indicated that 180–240 g/kg BY50 can be effectively used in shrimp diets as a replacement for FM, or up to 240 g/kg when replacing SBM.

Leveraging endogenous barley enzymes to turn lactose-containing dairy by-products into fermentable adjuncts for Saccharomyces cerevisiae-based ethanol fermentations

Acid whey, a by-product of strained yogurt production, represents a disposal challenge for the dairy industry. Utilization schemes are currently limited; however, acid whey contains valuable components that could be used to create value-added products. One potential scheme would be the fermentation of acid whey into an alcoholic beverage. Sour beers are gaining popularity and acid whey, which is sour to begin with, could provide a new product opportunity. However, the main sugar of acid whey, lactose, cannot be fermented by the traditional brewer's yeast, Saccharomyces cerevisiae. It has been reported that barley contains enzymes capable of hydrolyzing lactose to glucose and galactose, which are fermentable by S. cerevisiae. We investigated whether a barley-based mash resulted in detectable hydrolysis of lactose into sugars fermentable by S. cerevisiae. We demonstrated the ability to hydrolyze lactose in acid whey using a barley-based mash, resulting in the average release of 3.70 g/L of glucose. Additionally, the subsequent liquid was fermented by S. cerevisiae to an average ethanol concentration of 3.23% alcohol by volume. This work demonstrates the ability to hydrolyze the lactose in acid whey using barley and the opportunity to use acid whey as a fermentable sugar source in beer production.

Physiological Changes of Beer Brewer's Yeast During Serial Beer Fermentation

Serial repitching of beer brewer’s yeast plays an important role in the beer industry as an ineluctable economic factor. In this study, the viability and vitality changes, as well as strains’ anti-autolytic abilities during serial beer fermentation with typical ale and lager yeast strains, were investigated. While measuring the survival rate of yeast cells is not sufficient for evaluating and predicting the yeast fermentation capacity, physiological status determination of brewer’s yeast reflects the vitality and quality of yeast in serial beer fermentations. Accumulation of reactive oxygen species in yeast causes cell damage, leading to a decline in cell vitality and viability. Aged yeast cells, after several repitchings, can result in leakage of intracellular compounds into the fermented liquor. The lager yeast (Pilsner) examined, which harbors the partial genome from S. eubayanus, showed better robustness and higher activity than the ale yeast strain M79 examined, during serial fermentation. A holistic approach, including more indicators, should be applied in evaluating the fermentation performance of brewer’s yeast.

Growth performance of the edible mealworm species, Tenebrio molitor (Coleoptera: Tenebrionidae) on diets composed of brewer's yeast

Growth performance of the edible mealworm species, Tenebrio molitor (Coleoptera: Tenebrionidae) on diets composed of brewer's yeast

Saccharomyces: A Friend or Foe in ICU (A Case Report with Solution).

ABSTRACTSaccharomyces cerevisiae or boulardii, also known as baker's yeast or brewer's yeast, is normally a nonpathogenic microbe. It is commonly used as a probiotic to prevent antibiotic-associated diarrhea. We present a case of a 77-year-old woman with uncontrolled diabetes who developed Saccharomyces fungemia with use of Saccharomyces containing probiotic after 5 days of treatment. The probiotic was immediately discontinued. The indwelling central line was removed, she was started on amphotericin B and the fungemia resolved. This case report highlights this peculiar complication of probiotic use. We also find it important to increase the awareness amongst the healthcare providers about this likely risk while prescribing probiotics, especially for critically ill patients.How to cite this article: Gupta P, Singh YP, Taneja A. Saccharomyces: A Friend or Foe in ICU (A Case Report with Solution). Indian J Crit Care Med 2019;23(9):430–431.

Use of spent brewer's yeast in L-(+) lactic acid fermentation

Use of spent brewer's yeast in L-(+) lactic acid fermentation

A Study on the Quality Characteristics of Rice Beer Using Brewing Yeast isolated from Nuruk

A Study on the Quality Characteristics of Rice Beer Using Brewing Yeast isolated from Nuruk

Trace level voltammetric determination of Zn(II) in selected nutrition related samples by bismuth-oxychloride-multiwalled carbon nanotube composite based electrode

Bismuth-oxychloride-multiwalled carbon nanotube composite material was applied as surface modifier of glassy carbon electrode (BiOCl-MWCNT/GCE) for rapid and reliable trace level determination of Zn(II) in selected foodstuffs. The method development encompasses the optimization of electrode preparation including the transmission electron microscopic study of the modifier suspension, selection of the supporting electrolyte pH, the adjustment of the operation parameters of the SW-ASV measurements and the investigation of matrix effects. By the BiOCl-MWCNT/GCE recorded calibration curve showed an excellent linearity towards Zn reoxidation peak intensity in the concentration range from 2.50 to 80.0 μg L−1 with the calculated LOD of 0.75 μg L−1 which was associated with 120 s accumulation time and accumulation potential −1.40 V vs SCE in acetate buffer pH 4.5. A satisfactory repeatability expressed as relative standard deviation of 4.8% was obtained in the case of 10.0 μg L−1 Zn(II) in model solution. The Zn(II) reoxidation signal from BiOCl-MWCNT/GCE received by the optimized SW-ASV method was compared with those recorded with bare, classical bismuth-film, multiwalled carbon nanotubes and by in situ made advanced bismuth-film-MWCNTs working electrodes. The applicability of the proposed BiOCl-MWCNT/GCE based method was corroborated via measuring the target analyte in two nutrition related real samples: in a dietary supplement and in a brewer's yeast sample. Comparative flame atomic absorption spectrometric measurements verified the obtained results in the case of yeast sample.

Adaptation, chance, and history in experimental evolution reversals to unicellularity.

Evolution is often deemed irreversible. The evolution of complex traits that require many mutations makes their reversal unlikely. Even in simpler traits, reversals might become less likely as neutral or beneficial mutations, with deleterious effects in the ancestral context, become fixed in the novel background. This is especially true in changes that involve large reorganizations of the organism and its interactions with the environment. The evolution of multicellularity involves the reorganization of previously autonomous cells into a more complex organism; despite the complexity of this change, single cells have repeatedly evolved from multicellular ancestors. These repeated reversals to unicellularity undermine the generality of Dollo's law. In this article, we evaluated the dynamics of reversals to unicellularity from recently evolved multicellular phenotypes of the brewers yeast Saccharomyces cerevisae. Even though multicellularity in this system evolved recently, it involves the evolution of new levels of selection. Strong selective pressures against multicellularity lead to rapid reversibility to single cells in all of our replicate lines, whereas counterselection favoring multicellularity led to minimal reductions to the rates of reversal. History and chance played an important role in the tempo and mode of reversibility, highlighting the interplay of deterministic and stochastic events in evolutionary reversals.

Brewing and malting technology by‐products as raw materials in L‐(+)‐lactic acid fermentation

AbstractBACKGROUNDBrewer's spent grain (BSG), brewer's yeast (BY), malt rootlets (MR), and soy lecithin (SL) are valuable and abundant by‐products obtained from brewing, malting, and oil industry, respectively. L‐(+)‐lactic acid (LA) is organic acid that has a wide range of application. In this study hydrolysate obtained from BSG and MR mixture (BSGMR), was used in combination with SL and BY extract (BYE) in LA fermentation. The aim was to evaluate the effect and to optimize the addition of SL (0.1% and 0.2%) or BYE (10% and 20%) compared with Tween 80 (0.1%) and yeast extract (0.8%), in batch and fed‐batch LA fermentation.RESULTSUsing optimal SL and BYE concentrations (0.19% and 19.12%, respectively) obtained by response surface methodology (RSM), the highest LA concentration, yield, and volumetric productivity of 28.43 g L−1, 93.03%, and 1.04 g L−1 h−1, respectively, were achieved in batch fermentation, with further increase using fed‐batch fermentation (70.17 g L−1, 94.57%, and 1.22 g L−1 h−1, respectively).CONCLUSIONThe results achieved indicated that the combination of industrial by‐products, BSG, MR, SL, and BYE can be used as very suitable fermentation media for LA production, and that SL and BYE could be used as cheap replacements for Tween 80 and YE without decreasing fermentation efficiency. © 2018 Society of Chemical Industry

PSXVII-11 Effect of supplementation with brewer yeast hydrolysate on growth performance, blood profile, fecal score, fecal microbial, and rectal temperature in weanling pigs challenged with lipopolysaccharide.

PSXVII-11 Effect of supplementation with brewer yeast hydrolysate on growth performance, blood profile, fecal score, fecal microbial, and rectal temperature in weanling pigs challenged with lipopolysaccharide.

Brewing with malted barley or raw barley: what makes the difference in the processes?

Malted barley is the main source for fermentable sugars used by yeasts in the traditional brewing of beers but its use has been increasingly substituted by unmalted barley and other raw grain adjuncts in recent years. The incorporation of raw grains is mainly economically driven, with the added advantage of improved sustainability, by reducing reliance on the malting process and its associated cost. The use of raw grains however, especially in high proportion, requires modifications to the brewing process to accommodate the lack of malt enzymes and the differences in structural and chemical composition between malted and raw grains. This review describes the traditional malting and brewing processes for the production of full malt beer, compares the modifications to these processes, namely milling and mashing, when raw barley or other grains are used in the production of wort-a solution of fermentable extracts metabolized by yeast and converted into beer, and discusses the activity of endogenous malt enzymes and the use of commercial brewing enzyme cocktails which enable high adjunct brewing.