Distiller's Yeast Research Articles

Dietary supplementation of distiller's grains yeast cultures improves performance and immunity by altering the intestinal flora of broilers.

Distiller's grains are a by-product of liquor production with a higher yield than liquor. Developing and utilizing distiller's grains well could alleviate the problem of scarce feed resources. Our present experiment was conducted with 6000 yellow-feathered broilers to study the effects of adding distiller's grains yeast cultures (DGYC) to the diet on growth performance and immunity of broilers. The broilers were divided into five groups, receiving different DGYC concentrations during two stages. Growth performance, intestinal microorganisms and immune organ development were measured. The results showed that groups B and D, supplemented with medium and high concentrations of DGYC, respectively, had significantly improved growth performance compared to the control group (P < 0.05). Group D also showed higher immune organ index (P < 0.01), increased serum total protein, high-density lipoprotein and immunoglobulin levels (P < 0.05) and lower levels of low-density lipoprotein, triglycerides, interleukin 1β and tumor necrosis factor α (P < 0.05). Hematoxylin and eosin staining confirmed improved immune organ development in group D (P < 0.05). Furthermore, in high-concentration group D, levels of short-chain fatty acids (SCFA; acetic, propionic and butyric acids) in cecal chyme were significantly increased (P < 0.05). The richness (Chao1) and diversity (Faith-pd) index of cecal microbiota were significantly higher in group D compared to the control group (P < 0.05). The microbial composition in group D differed from the control and medium-concentration group B. Seven bacteria (Clostridia-UCG-014, UCG-009, DTU089, UCG-010, Campylobacter, Harryflintia, Shuttleworthia) showed significant differences (P < 0.05). After DGYC feeding, DTU089 decreased, while other SCFA-producing bacteria increased (P < 0.05). Subsequently, KEGG function and corresponding signal pathway predictions were performed on bacteria with significant differences. Group D exhibited a higher enrichment of immune function pathways (P < 0.01) and showed significant changes in four immune signaling pathways according to the signal pathway heatmap. Our data suggest that high concentrations of DGYC can be applied as a feed additive for broilers that promotes growth, improves intestinal health and enhances certain immunity. © 2024 Society of Chemical Industry.

Enhancing chain-elongating microbiomes: Sequential fungi-bacteria cooperation for efficient food waste upgrading using endogenous electron donors

The upgrading of organic waste such as food waste (FW) into medium-chain carboxylates (MCC) is within a bio-based circular economy concept. An efficient chain elongation (CE) microbiome is difficult to obtain, which normally requires long-term acclimatization and an exogenous supplement of electron donor (ED, especially ethanol). In this study, the CE microbiome was rapidly shaped within 18 days and an efficient endogenous ethanol-based CE was achieved through the amendment of distiller yeast (DY) during FW fermentation. Multiple FW feeding accumulated the caproate concentration to 5.76 ± 0.33 g COD/L, which also regulated the CE process from ethanol-dependent to lactate-dependent metabolism. During the lactate-based CE process, the caproate production increased linearly (R2 = 0.82) with the rising D-lactate content. Ethanol-producing fungi yeast mainly consisted of Wickerhamomyces (66.54 %), Saccharomycopsis (5.37 %), Issatchenkia (2.21 %), unclassified_f_Metschnikowiaceae (1.73 %), and Saccharomyces (1.33 %). These yeasts were eliminated by FW feeding, which was in line with the alteration of ED preference from ethanol to lactate. Metagenome analysis indicated that the total relative abundance of lactate-based chain elongators including Ruminococcaceae bacterium CPB6, Clostridium luticellarii, Caproiciproducens galactitolivorans, and Megasphaera elsdenii was increased by 28.6 %, while the ethanol-based chain elongator Clostridium kluyveri kept stable after FW feeding. In addition, the functional genes related to the oxidation of lactate to acetyl-CoA were enriched after FW feeding, which further enhanced the subsequent CE pathway of acetyl-CoA-based reverse β oxidation rather than the fatty acids synthesis. This study provides a new insight into upgrading FW into valuable MCC without exogenous ED addition.

The making method of Shen Qu in Qi Min Yao Shu

Shen Qu was distiller's yeast in Qi Min Yao Shu, the most completely preserved of the ancient Chinese agricultural texts in the North Dynasty. The making process of Shen Qu (medicated leaven) in this book had far-reaching influence on the processing of Liu Shen Qu. In terms of pharmaceutical composition, Flour-qu in Shen Qu, which developed into Whole-bran-wheat-qu and then Bran-qu, is still used up to this day. The use of polygonum, as a supplementary material from the buckwheat and knotweed family polygonaceae, was gradually narrowed to polygonum hydropiper and polygonum orientale. In terms of production and processing, fresh herbs were developed from boiling or boiling and juicing in parallel. Wheat processing was simplified from the method of raw wheat, steaming and frying together into the method of using raw wheat only. Psychrometrics of Qu-cake "Sou Yu Gang" is still taken as the measurement of production and processing today. The method of shaping Qu-cake evolved to hand kneading and moulding. The covering material of Qu-cake was developed from wheat straw and Artemisia annua to Vitex negundo. The wrapping material of Qu-cake were Ramie leaves, broussonetia papyrifera leaves and paper. Some techniques in the processing, such as Fan-qu, Ju-qu and Wengsheng, were lost in the historical development of the making method of Shen Qu. The drying method was developed from hanging clusters of Qu-cakes to hanging single paper wraped cakes alone. As a mainstream processing method, Yan-qu was then developed into the methods of Fengqu and Zao Jiang Huang. The making method Bao-qu, which outdated Qu was added, and is still the method of Yan-qu. In this sense, current production and processing technology of Yan-qu and Zao Jiang Huang came from Qi Min Yao Shu.The issues for further studies are: the use of Artemisia annua, Polygonum hydropiper and Xanthium sibiricum, Qu-cake moulding, single strain fermentation or dominant population fermentation, the Feng-qu method, the materials for covering and wrapping Qu-cake, and comparison between Flour-qu, Whole bran wheat- qu and Bran-qu.

Effect on hypoglycemic activity and UPLC–MS/MS profiling of Rosa roxburghii fruit fermented with Chinese traditional distiller's yeast

Effect on hypoglycemic activity and UPLC–MS/MS profiling of Rosa roxburghii fruit fermented with Chinese traditional distiller's yeast

Exploiting heterozygosity in industrial yeasts to create new and improved baker's yeasts.

The main aim of the work was to utilize heterozygosity of industrial yeast strains to construct new baker's yeast strains. Commercial baker's yeast strain ALKO 743, its more ethanol tolerant descendant ALKO 554 selected initially for growth over 300 generations in increasing ethanol concentrations in a glucose medium, and ALKO 3460 from an old domestic sour dough starter were used as starting strains. Isolated meiotic segregants of the strains were characterized genetically for sporulation ability and mating type, and the ploidy was determined physically. Heterozygosity of the segregant strains was estimated by a variety of molecular characterizations and fermentation and growth assays. The results showed wide heterozygosity and that the segregants were clustered into subgroups. This clustering was used for choosing distantly or closely related partners for strain construction crosses. Intrastrain hybrids made with segregants of ALKO 743 showed 16-24% hybrid vigour or heterosis. Interstrain hybrids with segregants of ALKO 743 and ALKO 3460 showed a wide variety of characteristics but also clear heterosis of 27-31% effects as assayed by lean and sugar dough raising. Distiller's yeast ALKO 554 turned out to be a diploid genetic segregant and not just a more ethanol tolerant mutant of the tetraploid parent strain ALKO 743.

An efficient method for isolating mating-competent cells from bottom-fermenting yeast using mating pheromone-supersensitive mutants.

Crossbreeding is an effective approach to construct novel yeast strains with preferred characteristics; however, it is difficult to crossbreed strains of brewer's yeast, especially the bottom-fermenting yeast Saccharomyces pastorianus, because of the relative inefficiency of the available methods to obtain mating-competent cells (MCCs). Here, we describe a productive method for the isolation of MCCs without artificial genetic modification. We focused on the characteristics of two mating pheromone-supersensitive mutants, Δbar1 and Δsst2, that show a growth defect in the presence of the mating pheromone. When MCCs secreting α-factor and a-factor were spotted on to a lawn of MATa Δbar1 and MATα Δsst2, a halo was observed around the respective MCCs. This plate assay was successful in identifying MCCs from bottom-fermenting yeast strains. Furthermore, by selecting for cells that caused the growth defect in pheromone-supersensitive cells on cultures plates, 40 α/α-type and six a/a-type meiotic segregants of bottom-fermenting yeast strains were successfully isolated and crossed with tester strains to verify their mating type. This method of isolation is expected to be applicable to other industrial yeast strains, including wine, sake and distiller's yeasts, and will enable MCCs without genetic modifications to be obtained. As a result, it will be a useful tool for more convenient and efficient crossbreeding of industrial yeast strains that can be applied to practical brewing. Copyright © 2017 John Wiley & Sons, Ltd.

Review of Second Generation Bioethanol Production from Residual Biomass.

In the context of climate change and the depletion of fossil fuels, there is a great need for alternatives to petroleum in the transport sector. This review provides an overview of the production of second generation bioethanol, which is distinguished from the first generation and subsequent generations of biofuels by its use of lignocellulosic biomass as raw material. The structural components of the lignocellulosic biomass such as cellulose, hemicellulose and lignin, are presented along with technological unit steps including pretreatment, enzymatic hydrolysis, fermentation, distillation and dehydration. The purpose of the pretreatment step is to increase the surface area of carbohydrate available for enzymatic saccharification, while minimizing the content of inhibitors. Performing the enzymatic hydrolysis releases fermentable sugars, which are converted by microbial catalysts into ethanol. The hydrolysates obtained after the pretreatment and enzymatic hydrolysis contain a wide spectrum of sugars, predominantly glucose and xylose. Genetically engineered microorganisms are therefore needed to carry out co-fermentation. The excess of harmful inhibitors in the hydrolysate, such as weak organic acids, furan derivatives and phenol components, can be removed by detoxification before fermentation. Effective saccharification further requires using exogenous hemicellulases and cellulolytic enzymes. Conventional species of distiller's yeast are unable to ferment pentoses into ethanol, and only a very few natural microorganisms, including yeast species like Candida shehatae, Pichia (Scheffersomyces) stipitis, and Pachysolen tannophilus, metabolize xylose to ethanol. Enzymatic hydrolysis and fermentation can be performed in a number of ways: by separate saccharification and fermentation, simultaneous saccharification and fermentation or consolidated bioprocessing. Pentose-fermenting microorganisms can be obtained through genetic engineering, by introducing xylose-encoding genes into metabolism of a selected microorganism to optimize its use of xylose accumulated in the hydrolysate.

The effect of apple cultivars and yeast strains on selected quality parameters and antioxidant activity of fermented apple beverages

ABSTRACTThe aim of the study was to evaluate the impact of selected apple cultivars (Rubin, Topaz, Elise) and selected strains of wine, cider, distiller yeast, and wild-type yeast on the dynamics of the fermentation process as well as on the chemical composition and antioxidant properties (AOX) of fermented apple beverages. The quality parameters of the fermented beverages depend mainly on the apple cultivar used. The beverages from the Rubin cultivar met all the requirements for fruit wines, but in the beverages from the Topaz cultivar, the limit values for total acidity were exceeded (> 7g/L). The beverages from the Elise cultivar were characterized by low ethanol content and degree of fermentation. The process of fermentation resulted in a reduction of the total polyphenol content (TPC) in the beverages of the Rubin and Topaz cultivars, while in beverages from the Elise cultivar, in an increase of both TPC and AOX.Abbreviations: AOX - antioxidant activity; TPC - total polyphenol content; FAN - free amino nitrogen; ABTS - diammonium salt of the 2,2ʹ-azino-bis(3-ethylbenzothiazoline-6-sulfonic) acid.

Distiller yeasts producing antibacterial peptides

A new method of controlling lactic acid bacteria contamination was developed with the use of recombinant Saccharomyces cerevisiae strains producing antibacterial peptides. Genes encoding the antibacterial peptides pediocin and plantaricin with codons preferable for S. cerevisiae were synthesized, and a system was constructed for their secretory expression. Recombinant S. cerevisiae strains producing antibacterial peptides effectively inhibit the growth of Lactobacillus sakei, Pediacoccus pentasaceus, Pediacoccus acidilactici, etc. The application of distiller yeasts producing antibacterial peptides enhances the ethanol yield in cases of bacterial contamination. Recombinant yeasts producing the antibacterial peptides pediocin and plantaricin can successfully substitute the available industrial yeast strains upon ethanol production.

Exploiting Issatchenkia orientalis SD108 for succinic acid production.

BackgroundRecent advances in synthesizing valuable chemicals such as organic acids from low-cost renewable biomass through microbial fermentation have attracted great attention. However, the toxicity of organic acids presents a key challenge to the development of an economically viable fermentation process. Therefore, a platform organism that not only produces organic acids but also tolerates the associated toxicity is highly desirable.ResultsHere we report the discovery, characterization, and engineering of a yeast strain, Issatchenkia orientalis SD108, that is tolerant to low pH and high concentration of organic acids. This strain demonstrated a higher tolerance compared to I. orientalis ATCC 24210 and Classic Distiller’s Turbo yeast. In order to explore SD108 as a potential platform organism for organic acid production, we determined its draft genome sequence and use the sequencing information to guide pathway design. As proof of concept, an engineered four-gene expression cassette related to the reductive TCA cycle was assembled and integrated into the genome of a uracil auxotroph of SD108. The resulting strain was able to produce succinic acid with a titer of 11.63 g/L, yield of 0.12 g/g, and productivity of 0.11 g/L · h in batch cultures using shake flasks.ConclusionsThe high tolerance of I. orientalis SD108 towards multiple important organic acids makes it a highly attractive organism as a platform host for producing this group of compounds as it will reduce production cost, facilitate downstream processing, and serve as a host for construction of production strains with both pH and specific anion tolerance.Electronic supplementary materialThe online version of this article (doi:10.1186/s12934-014-0121-4) contains supplementary material, which is available to authorized users.

Intergeneric yeast fusants with efficient ethanol production from cheese whey powder solution: Construction of aKluyveromyces marxianusandSaccharomyces cerevisiaeAY-5 hybrid

Due to its high content of lactose and abundant availability, cheese whey powder (CWP) has received much attention for ethanol production in fermentation processes. However, lactose-fermenting yeast strains including Kluyveromyces marxianus can only produce alcohol at a relatively low level, while the most commonly used distiller yeast strain Saccharomyces cerevisiae cannot ferment lactose since it lacks both β-galactosidase and the lactose permease system. To combine the unique aspects of these two yeast strains, hybrids of K. marxianus TY-22 and S. cerevisiae AY-5 were constructed by protoplast fusion. The fusants were screened and characterized by DNA content, β-galactosidase activity, ethanol tolerance, and ethanol productivity. Among the genetically stable fusants, the DNA content of strain R-1 was 6.94%, close to the sum of the DNA contents of TY-22 (3.99%) and AY-5 (3.51%). The results obtained by random-amplified polymorphic DNA analysis suggested that R-1 was a fusant between AY-5 and TY-22. During the fermentation process with CWP, the hybrid strain R-1 produced 3.8% v/v ethanol in 72 h, while the parental strain TY-22 only produced 3.1% v/v ethanol in 84 h under the same conditions.

Research on Enzymological Characteristics of Moulds from Distiller's Yeast

The experiment has studied the enzymological characteristics of 5 moulds isolated from the distillery yeast, which determined the best condition of culture for the production of saccharifying enzyme and liquifying enzyme. The result has shown that the activity of saccharifying enzyme and liquifying enzyme is higher when the culture time is 5d and when the pH is 5.8. The best pH action ranges from 5.2~7.0; The activity begins to fall when the content of alcohol in the culture solution is more than 60%. The activity of saccharifying enzyme and liquifying enzyme of the 5 moulds changes as the time of culture differs. The longest time of the culture of enzyme is 3~5 d. The pH when the activity of saccharifying enzyme and liquifying enzymeranges of the five moulds is highest ranges from 5.2~7.0 , and it will fall when the pH is meta-acid or meta soda. It’s predited that the activity of enzyme will lose when meta-acid or meta-soda.

Determination of tetrodotoxin in fermentation broth of distiller’s yeast by ion chromatography

A method was developed for the quantitative analysis of tetrodotoxin (TTX) in fermentation broth of distiller's yeast by ion chromatography. After extraction with acetonitrile solution (containing 0.1% phosphoric acid) and purification with an ion-exchange column, the tetrodotoxin was separated by ion chromatography and detected by a ultraviolet-visible (UV-VIS) absorbance detector. The experimental results showed that the tetrodotoxin had a good linearity (r2 = 0.997) in the range of 10 - 100 mg/L and the detection limit (3 of signal-to-noise ratio) was 1.0 mg/L. The average recoveries were between 90% - 103% with a relative standard deviation lower than 4.9%. The analysis of real samples verified the reliability of this method and demonstrated that the ion chromatography can be used for the quantification detection of the tetrodotoxin. The degradation experiment results suggested that distiller's yeast had a remarkable effect on the tetrodotoxin degradation.

Influence of Zinc on Distiller's Yeast: Cellular Accumulation of Zinc and Impact on Spirit Congeners

Accumulation of zinc by a whisky distilling yeast strain of Saccharomyces cerevisiae was studied during fermentation of malt wort and synthetic defined medium. Zinc uptake by yeast cells was very rapid in malt wort, as zinc (0.32 μg/mL) was completely removed from the fermentation medium within one hour. The type of fermentable carbohydrate had an impact on the kinetics of zinc accumulation, with maltose most effective at enhancing metal uptake at zinc concentrations above 3.2 μg/mL. Enriching yeast cells with zinc by preconditioning impacted on the production of flavour congeners in the distillates produced from fermented cultures. Such distillates were characterised by an altered flavour and aroma profile. In particular, the production of some higher alcohols increased when yeast cells were preconditioned with zinc. This phenomenon is yeast strain related. Industrial fermentation processes, including brewing and distilling, may benefit from optimization of zinc bioavailability in yeast cultures resulting in more efficient fermentations and improved product quality.

Stereospecificity of 10-Hydroxystearic Acid and Formation of 10-Ketostearic Acid by Lactic Acid Bacteria

We studied the variation in enantiomeric excess of 10-hydroxystearic acid (10-HSA) produced by several strains of lactic acid bacteria from oleic acid. Using 1H-nuclear magnetic resonance and chiral-phase HPLC to reveal the microorganisms involved and the mechanisms of the formation, we found that most strains produced nearly optically pure (R)-10-HSA. Among them, one strain of Lactobacillus hilgardii, isolated from a distillery in Scotland, produced 10-HSA with lower enantiomeric excess, and furthermore, the strain produced a large amount of 10-ketostearic acid along with the 10-HSA. In this strain, 10-ketostearic acid was found to be generated from 10-HSA supplied to the cells. Also, the enantiomeric excess of γ-dodecalactone, formed from 10-ketostearic acid by distiller's yeasts, was found to be within the range of −17 to 32%; these findings were consistent with the distribution of the enantiomers in malt whiskies. From these results, two conceivable pathways for the formation of lactones during the production of malt whisky were proposed: from 10-ketostearic acid with the involvement of distiller's yeast and from nondistiller's yeast with 10-HSA as an intermediate.

HO gene polymorphism in Saccharomyces industrial yeasts and application of novel HO genes to convert homothallism to heterothallism in combination with the mating-type detection cassette

Southern blot analysis of industrial yeasts showed that all top-fermenting yeasts, distiller's yeasts and a proportion of wine yeasts tested in the present study produced a hybridization signal (approximately 7 kb), corresponding to a Saccharomyces cerevisiae-type HO gene (Sc-HO). It also showed that bottom-fermenting yeasts gave rise to 7-kb and 4-kb hybridization signals, corresponding to the Sc-HO gene and the lager yeast HO gene (Lg-HO), respectively. Two wine yeasts produced a 4-kb hybridization signal, corresponding to Lg-HO; and one wine yeast produced 2.5-kb and 1.5-kb hybridization bands, corresponding to a S. uvarum-type HO gene (Uv-HO). Partial nucleotide sequences of HO genes amplified from these wine yeasts perfectly matched those of Lg-HO and Uv-HO, respectively. HO disruption vectors were constructed by inserting a dominant selective marker PGK1p-neo and the mating-type detection cassette MFalpha1p-PHO5 within the Lg-HO or Uv-HO gene. From transformants carrying a single-disrupted ho gene, mating-competent progenies were easily obtained through meiosis. Moreover, mating-competent derivatives appearing at very low frequency could be obtained from a double-disrupted ho transformant without meiosis (even from a wine yeast lacking sporulation ability), because the sensitive phosphatase-staining method allowed detection of the Pho+ mating-competent derivatives from confluent colonies by the random spore method. Our study describes a rapid and convenient method for isolating mating-competent clones from industrial yeasts.

Incidence of SUC-RTM telomeric repeated genes in brewing and wild wine strains of Saccharomyces.

When over-expressed, RTM yeast genes confer resistance to the toxicity of molasses. They are found in distiller's and baker's industrial yeasts in multiple copies, scattered on the telomeres and physically linked to the telomeric SUC genes. Because these genes are absent from some laboratory strains, we explored the genomes of other industrial yeasts (brewing strains) and wine wild strains. A collection of 47 wine yeast strains (S. cerevisiae and S. bayanus) and 15 brewing strains, lager, ale and possible ancestors (S. monacensis, S. paradoxus and S. carlsbergensis) were screened for the presence of RTM genes. Only three wine strains and all brewing strains proved to contain RTM sequences in different copy numbers. PCR and chromosome blotting confirm the presence of SUC sequences in tandem with RTM. Moreover, analysis of the entire S. cerevisiae genome sequence shows that three other, non-telomeric, genes related to RTM are scattered on different chromosomes.

A strategy for construction of industrial strains of distiller's yeast

A procedure was developed for construction of industrial strains of distiller's yeast (Saccharomyces cerevisiae). It includes several steps: construction of congenic genetically marked haploid strains of opposite mating types starting from an industrial strain of hybrid nature, integrative transformation of the above haploid strains with a DNA fragment containing an expression cassette responsible for new technological facilities, and hybridization of transformants and isolation of final industrial homozygous strains under experimental conditions simulating commercial fermentation processes. This strategy permits the generation of strains that have desirable characteristics of traditional races of distiller's yeast along with new technological facilities determined by the particular expression cassette. Using this procedure, we have constructed an industrial strain with improved amylolytic activity. (c) 1995 John Wiley & Sons, Inc.

Fermentation of lactose by yeast cells secreting recombinant fungal lactase.

Strains of Saccharomyces cerevisiae transformed with a yeast multicopy expression vector carrying the cDNA for Aspergillus niger secretory beta-galactosidase under the control of ADH1 promoter and terminator were studied for their fermentation properties on lactose (V. Kumar, S. Ramakrishnan, T. T. Teeri, J. K. C. Knowles, and B. S. Hartley, Biotechnology 10:82-85, 1992). Lactose was hydrolyzed extracellularly into glucose and galactose, and both sugars were utilized simultaneously. Diauxic growth patterns were not observed. However, a typical biphasic growth was observed on a mixture of glucose and galactose under aerobic and anaerobic conditions with transformants of a haploid S. cerevisiae strain, GRF167. Polyploid distiller's yeast (Mauri) transformants were selected simply on the basis of the cloned gene expression on X-Gal (5-bromo-4-chloro-3-indolyl-beta-D-galactopyranoside) plates. Rapid and complete lactose hydrolysis and higher ethanol (0.31 g/g of sugar) and biomass (0.24 g/g of sugar) production were observed with distiller's yeast grown under aerobic conditions. A constant proportion (10%) of the population retained the plasmid throughout the fermentation period (48 h). Nearly theoretical yields of ethanol were obtained under anaerobic conditions on lactose, glucose, galactose, and whey permeate media. However, the rate and the amount of lactose hydrolysis were lower under anaerobic than aerobic conditions. All lactose-grown cells expressed partial galactokinase activity.

Some effects of lactic acid bacteria on laboratory-scale yeast fermentations

A laboratory-scale system, involving the mashing of distiller's malt and the fermentation of the resulting wort by distiller's yeast, was used to simulate commercial-scale malt whisky fermentations. Deliberate addition of pure cultures of lactic acid bacteria, previously isolated from a commercial malt whisky distillery, permitted the effects of bacterial contamination to be studied under controlled conditions. Bacterial contamination led to reduced yields of ethanol, lower yeast crops, reduced carbohydrate utilization, greatly increased acidity due mainly to production of lactic acid, and lower final pH. Contaminated fermentations showed greatly increased foam production. Certain bacterial strains caused premature flocculation of yeast cells. Reduced ethanol yields were not due simply to competition for carbohydrate: other likely mechanisms for the effect are discussed.