Yeast Production Research Articles

Improvement of (Eruca sativa Mill) yield, oil, chemical constituents and antioxidant activity utilizing a by-product of yeast production (CMS) with zinc and boron under salinity stress conditions

The impact of low-quality irrigation water on plant development has garnered significant attention from researchers. In light of this, two field experiments were conducted to evaluate the performance, yield, oil production and composition, as well as active constituents of Rocket (Eruca sativa Mill) cultivated in calcareous soil under saline water irrigation. Foliar sprays containing condensed molasses soluble (CMS), zinc (Zn), and boron (B) alone or in combination were used for irrigation. The data obtained from measuring various parameters of Rocket following foliar spraying with CMS, Zn, B or their combinations demonstrated that most treatments resulted in a significant increase in these parameters. The highest values for most measurements were observed when foliar application included all three components (CMS ​+ ​Zn ​+ ​B), resulting in a seed yield of 184.6 ​g/m2 and an oil content of 675.3 ​kg/ha. Compared to the control group, the macronutrient content of N, P, K, Mg, and Ca increased by 34.4%, 56%, 42%, 45%, and 39% respectively in the seeds treated with these components. Furthermore, carbohydrates, proteins, phenolics flavonoids, and antioxidants showed increases of 24%, 34%, 21%, 43%, and 28% respectively compared to the control group. Gas-liquid chromatography analysis identified ten components present in the seed oil characterized by higher unsaturated fatty acids ranging from 81.28% to 92.28% and lower saturated fatty acids ranging from 6.72% to 8.21%. Therefore, foliar spray application including CMS, zinc, and boron can help alleviate salinity effects on Rocket plants grown under saline water irrigation conditions while improving growth, yield, oil production, and nutritional content such as total carbohydrates, proteins, and macronutrients levels.

Effect of Yeast Cell Wall on Gut Health, Immunity and Milk Production of Dairy Cattle in Normal and Heat Stress Conditions. Review

This review focuses on the most recent literature to bring to light the major beneficial effects of the yeast cell wall (YCW) and its products on dairy cattle. These products include viable yeast, yeast culture, nutritional yeast, and fractionated yeast products. The yeast cell wall is one of these products and belongs to the fractionated yeast products used to promote production performance and health in dairy cows. The yeast and YCW were proven to have positive impacts on dairy cattle performance in terms of milk yield, milk components, and overall quality. As well, these products showed beneficial effects under heat stress conditions. The YCW is a natural fermentation derivative of yeast cells such as Saccharomyces cerevisiae species consists mainly of β-glucan (29% to 64%), mannan (31%), and some other compounds like protein (13%), lipids (9%), chitin (1–2%) with β-glucan and mannan being the main bioactive molecules. The mode of action through which YCW elicit their beneficial functions in dairy cow explain their effect on cows' metabolism and digestion, immunity, rumen and intestine health, and subsequent performance and well-being. These modes of action include improving gastrointestinal (GI) tract health, stimulating immune system components as it is considered an immunomodulator additive, mycotoxin binding ability, and improving antioxidant capacity. Therefore, yeast and YCW products are one of the promising areas of ruminant nutrition in dairy cows, not only because of their nutritional and health benefits to dairy cows but also due to their negligible residual effects on dairy cows’ bodies and products.

Fine-tuning of p-coumaric acid synthesis to increase (2S)-naringenin production in yeast

(2S)-Naringenin is a key precursor for biosynthesis of various high-value flavonoids and possesses a variety of nutritional and pharmaceutical properties on human health. Systematic optimization approaches have been employed to improve (2S)-naringenin production in different microbial hosts. However, very few studies have focused on the spatiotemporal distribution of (2S)-naringenin and the related pathway intermediate p-coumaric acid, which is an important factor for efficient production. Here, we first optimized the (2S)-naringenin biosynthetic pathway by alleviating the bottleneck downstream of p-coumaric acid and increasing malonyl-CoA supply, which improved (2S)-naringenin production but significant accumulation of p-coumaric acid still existed extracellularly. We thus established a dual dynamic control system through combining a malonyl-CoA biosensor regulator and an RNAi strategy, to autonomously control the synthesis of p-coumaric acid with the supply of malonyl-CoA. Furthermore, screening potential transporters led to identification of Pdr12 for improved (2S)-naringenin production and reduced accumulation of p-coumaric acid. Finally, a titer of 2.05 g/L (2S)-naringenin with negligible accumulation of p-coumaric acid was achieved in a fed batch fermentation. Our work highlights the importance of systematic control of pathway intermediates for efficient microbial production of plant natural products.

Meta-analysis of the effect of feeding live yeast (<em>Saccharomyces cerevisiae</em>) on feeding behaviour and lactation performance, rumen fermentation, and rumen microbiota in dairy cattle

Meta-analysis of the effect of feeding live yeast (<em>Saccharomyces cerevisiae</em>) on feeding behaviour and lactation performance, rumen fermentation, and rumen microbiota in dairy cattle

Conversion of Problematic Winery Waste into Valuable Substrate for Baker's Yeast Production and Solid Biofuel: A Circular Economy Approach§.

Wine production, which is considered a major sector in food industry, often involves the use of a large amount of resources. Moreover, wine making generates a large amount of grape pomace, which is generally used for low-value applications such as fertiliser and animal feed. The aim of the present research is to explore the possibility of improving the overall sustainability of traditional winemaking. A zero-waste process was developed. It includes the production of white wine and the substantial valorisation of grape pomace, which is converted into solid biofuel, tartaric acid and concentrated grape extract as feedstock for industrial baker's yeast production. We estimate that a significant surplus of renewable energy of approx. 3 MJ/kg processed grapes can be obtained during this conversion. The suitability of grape extract as a potential substrate for industrial baker's yeast production was evaluated and the feasibility of a partial replacement of molasses (up to 30 %) was demonstrated. We present a circular economy approach for the conversion of winery biowaste into high-value resources such as feedstock and solid biofuel.

ЗНИЖЕННЯ ЕВТРОФІКАЦІЇ ТА ЗАБРУДНЕННЯ ВОДОЙМ ЗА ДОПОМОГОЮ ВОДЯНОГО ГІАЦИНТУ

In this work, the problem of cleaning eutrophicated water bodies of the Southern Bug basin with the help of higher aquatic vegetation is analyzed using the example of water hyacinth. The possibility of effective use for water purification of Eichhornia plants in Podillia reservoirs has been established. The possibility of additional use of plants of the Eichhornia variety as a component of biofeeds, for the production of fodder yeast and flour, and for the production of various types of biofuels has also been established.

Study of the key biotic and abiotic parameters influencing ammonium removal from wastewaters by Fe3+-mediated anaerobic ammonium oxidation (Feammox)

The release of ammonia (as NH4+) into water bodies causes serious environmental problems. Therefore, the removal of ammonia from wastewater effluents has become a worldwide concern. New autotrophic biological alternatives for ammonia removal could reduce the limitations of conventional organic carbon-dependent nitrification-denitrification methods. Here, the potential of anaerobic ammonium oxidation coupled to Fe3+ reduction (a process known as Feammox) is studied in wastewater treatment plants of the yeast and beer production industry, not related to ammonium or iron treatment. This process is presented as a viable option to improve the efficiency of ammonia removal from wastewater. The results of this study show that enrichments under Feammox conditions achieved removals of 28.19–32.25% of the total NH4+. The highest rates of ammonium removal and Fe3+ reduction were achieved using FeCl3 as iron source and pH = 7.0. Different environmental conditions for the enrichments were studied and it was found that the use of sodium acetate as a carbon source and an incubation temperature of 35 °C presented higher rates of iron reduction and higher increase in nitrate concentration, related to ammonium oxidative processes. Likewise, the presence of relevant species of the iron and nitrogen cycles as Ferrovum myxofaciens, Geobacter spp, Shewanella spp, Albidiferax ferrireducens and Anammox was verified, supporting the findings of this study. These results provide information that may be relevant to the potential applicability of Feammox to treat wastewater with high ammonia load and could help develop cost-effective and environmentally friendly methods for ammonium removal in wastewater treatment plants.

Plasmid Copy Number Engineering Accelerates Fungal Polyketide Discovery upon Unnatural Polyketide Biosynthesis.

Saccharomyces cerevisiae has been extensively used as a convenient synthetic biology chassis to reconstitute fungal polyketide biosynthetic pathways. Despite progress in refactoring these pathways for expression and optimization of the yeast production host by metabolic engineering, product yields often remain unsatisfactory. Such problems are especially acute when synthetic biological production is used for bioprospecting via genome mining or when chimeric fungal polyketide synthases (PKSs) are employed to produce novel bioactive compounds. In this work, we demonstrate that empirically balancing the expression levels of the two collaborating PKS subunits that afford benzenediol lactone (BDL)-type fungal polyketides is a facile strategy to improve the product yields. This is accomplished by systematically and independently altering the copy numbers of the two plasmids that express these PKS subunits. We applied this plasmid copy number engineering strategy to two orphan PKSs from genome mining where the yields of the presumed BDL products in S.cerevisiae were far too low for product isolation. This optimization resulted in product yield improvements of up to 10-fold, allowing for the successful isolation and structure elucidation of new BDL analogues. Heterocombinations of these PKS subunits from genome mining with those from previously identified BDL pathways led to the combinatorial biosynthesis of several additional novel BDL-type polyketides.

Bioutilization of the distillery stillage of different grain species from bioethanol production

Wastewater from bioethanol plants is classified as highly concentrated in terms of organic pollution precisely due to distillery stillage. The main problem in the disposal of distillery stillage is the processing of the liquid phase, the volume of which is up to 92% of all wastewater from a bioethanol plant. The existing wastewater treatment technologies of a bioethanol plant can be conditionally divided into four types: evaporation, aerobic biological treatment with fodder yeast production, anaerobic stillage treatment with biogas production, combined schemes. The aim of our work was to study a combined method for cleaning grain stillage by the anaerobic-aerobic method with the immobilization of microorganisms on a fibrous carrier. Physicochemical parameters of grain stillage and purified methane mash were determined according to generally accepted methods for analyzing wastewater from distilleries. Under anaerobic conditions, biogas was formed from distillery stillage, including low molecular weight organic compounds – methane, carbon dioxide, organic acids. After the first anaerobic stage of treatment, the pollution of wastewater decreased by 8-10 times, after which it was fed to the aerobic stage of post-treatment, which was carried out by microorganisms immobilized on a fixed carrier, which reduced the removal of biomass with the flow of purified water and improved treatment performance. The chemical oxygen demand (COD) of methane mash after the 1st stage of anaerobic fermentation was 1360 mg/dm3 compared to the initial COD of grain stillage of 15800 mg/dm3, which ensured a purification efficiency of 91.4%. The purification efficiency according to biochemical oxygen demand in five days (BOD5) was 97.5%. After the aerobic stage, the purification efficiency was 98.2% in terms of COD and 99.8% in terms of BOD5. The values of the content of total phosphorus also decreased by almost 20 times, nitrogen – by 9 times, sulfates – by 5 times. The advantages of the proposed method of wastewater treatment of bioethanol plants over existing ones are the ability to treat wastewater with any concentration of pollutants and additional obtaining of fuel – biogas, which can be used to replace natural gas, solving the problem of removing the biomass of microorganisms from the purification zone due to their fixation on a fibrous fixed carrier.

Research Note: Preliminary assessment of the impact of dietary yeast products on egg production and cecal microbial profiles of laying hens

The objective of the current study was to conduct an initial comparison of commercial yeast products in layer hen diets on egg production parameters and the corresponding impact on the cecal microbiota. A short-term feeding study was conducted with 35 laying hens receiving either a control, or 1 of 4 different yeast fermentation products, Immunowall, Hilyses (both from ICC, São Paulo, Brazil), Citristim (ADM, Decatur, IL), and Maxi-Gen Plus (CBS Bio Platforms, Calgary, Canada) with 7 hens per treatment from 40 to 46 wk of age. At the end of the trial, hens were euthanized, the ceca removed and prepared for denatured gradient gel electrophoresis (DGGE) microbial compositional analyses. Although initial shell weight and shell thickness were similar among the treatment groups, hens fed Hilyses had lower shell weight and thickness at the end of the experiment. The most predominant DGGE bands with the strongest intensity were identified as Lactobacillus species and excised double bands were identified as Bacillus, Clostridium, or Lachnospiraceae. In this short-term feeding trial, the commercial yeast products tested had little effect on egg production and shell quality, and only moderately impacted the composition of mature layer hen cecal microbiota.

Potential xylose transporters regulated by CreA improved lipid yield and furfural tolerance in oleaginous yeast Saitozyma podzolica zwy-2-3

Lignocellulose's hydrolysate, a significant renewable source, contains xylose and furfural, making it challenging for industrial production of oleaginous yeast. On xylose fermentation with furfural treatment, OE::DN7263 and OE::DN7661 increased lipid yield and furfural tolerance versus WT, while, which of OE::CreA were decreased owing to CreA regulating DN7263 and DN7661 negatively. OE::CreA generated reactive oxygen species (ROS) causing oxidative damage. OE::DN7263, OE::DN7661, and ΔCreA reduced furfural via NADH; while ΔCreA produced less ROS and OE::DN7263, and OE::DN7661 scavenged ROS quickly, minimizing oxidative damage. Overall, CreA knockout increased DN7263 and DN7661 expression to facilitate xylose assimilation, enhancing NADH generation and ROS clearance. Finally, with mixed sugar fermentation, ΔCreA and OE::DN7263′s biomass and lipid yield rose without furfural addition, while that of ΔCreA remained higher than WT after furfural treatment. These findings revealed how oleaginous yeast zwy-2–3 resisted furfural stress and indicated ΔCreA and OE::DN7263 might develop into robust industrial chassis strains.

Combining Protein and Organelle Engineering for Linalool Overproduction in Saccharomyces cerevisiae.

Linalool, a plant-derived high-value monoterpene, is widely used in the perfume, cosmetic, and pharmaceutical industries. Recently, engineering microbes to produce linalool has become an attractive alternative to plant extraction or chemical synthesis approaches. However, the low catalytic activity of linalool synthase and the shortage of precursor pools have been considered as two key factors for low yields of linalool. In this study, we rationally engineered the entrance of the substrate-binding pocket of linalool synthase (t67OMcLISM) and successfully increased the catalytic efficiency of this enzyme toward geranyl pyrophosphate. Specifically, F447E and F447A, with decreased entrance hydrophobicity and steric hindrance, increased linalool production by 2.2 and 1.9 folds, respectively. Subsequently, cytoplasm and peroxisomes were harnessed to boost linalool synthesis in Saccharomyces cerevisiae, achieving a high titer of linalool (219.1 mg/L) in shake-flask cultivation. Finally, the engineered diploid strain produced 2.6 g/L of linalool by 5 L fed-batch fermentation, which was the highest production in yeast to date. The protein engineering and biosynthetic pathway compartmentalization in the peroxisome provide references for the microbial production of other monoterpenes.

Methods to Improve Alcohol Fermentation Process: A Review

Biofuel has been a hot research topic in the 21st century because it is promising to gradually replace today’s traditionalfuel in the future, which can protect the earth from many aspects. For example, biofuel’s biodegradability can reducepollution and solve the problem of the energy crisis to a certain extent. This paper mainly takes ethanol fuel as theresearch object focuses on the mechanism of yeast production of biofuel, different production methods, and benefits ofyeast, and discusses the future of isobutanol, a more efficient biofuel with more significant potential.

Regulation of fructose levels on carbon flow and metabolites in yeast during food fermentation.

In this study, the effects of fructose levels on yeast growth, metabolic pathways and products, and redox status were investigated by simulated dough medium. The results showed that yeast was subjected to oxidative stress and damage under both sugar-free and high-fructose conditions. Yeast has a strong ability to metabolize pentose phosphate, trehalose, and tricarboxylic acid under sugar-free conditions. In the high fructose environment, yeast preferentially produced trehalose and glycerol in the early stage and gradually increased the metabolism of pentose phosphate in the later stage. Compared with the low fructose concentration, yeast had stronger pentose phosphate and tricarboxylic acid cycle (TCA) metabolism to ensure nicotinamide adenine dinucleotide phosphate (NADPH) and adenosine triphosphate (ATP) content in higher fructose levels. Therefore, sugar-free and high fructose levels affected the growth of yeast cells and yeast responded to fructose levels by regulating the metabolic carbon flow of glycolysis, pentose phosphate, trehalose, and TCA.

Study of Influence of Air Ions on the Growth Rate of Yeast Saccharomyces cerevisiae Based on Analytical Growth Model

The influence of the concentration of ions in a nutrient medium both on the surface charge and potential of a yeast cell and diffusion of nutrients through its membrane and on the productivity of baking yeast was studied theoretically. It was shown that the ionized molecules of air components (first of all, of oxygen and nitrogen) changes the concentration of ions in the medium, the surface charge and potential of the yeast cell. This feature affects the diffusion of nutrients through membrane into the cell. The growth rate of the yeast mass depends on the amount of electricity, transported by air ions in the nutrient medium, and is limited by its certain value. That is why the yeast mass growth equation take into account the amount of electricity transported by air ions into the nutrient medium. A priori calculation shows that the productivity of the baker’s yeast can increase by 12…17%.

Yeast-Based Whole-Cell Factory for the Ecofriendly Synthesis of Vanillylamine as a Critical Step toward Capsaicin Production

Capsaicin is a biologically active alkaloid with important pharmaceutical, food, and cosmetic applications. As capsaicin production is dependent on its extraction from plants, its industrial separation and purification capacity is greatly limited. The chemical synthesis of capsaicin via the Schotten–Baumann reaction requires vanillylamine and 8-methyl-6-nonenoic acid as reaction substrates. Currently, petrochemical products obtained by the catalysis of precious metals are used to produce vanillylamine; however, this approach does not meet the requirements advocated by the green chemical industry. Herein, we developed an efficient yeast-based whole-cell factory for the de novo biosynthesis of vanillylamine and capsaicin. A heterologous recombinant vanillylamine biosynthetic pathway in yeast yielded 6.47 g/L vanillylamine. Enhancing the phenylalanine pool by upregulating the shikimic acid pathway led to an 11% increase in vanillylamine production. Optimization of methyl transfer efficiency via a reconstituted S-adenosylmethionine (SAM) circulating cycle resulted in an 84% increase in vanillylamine production. Switching the yeast strain from Z2 to Z6 and rewiring the precursor pool and SAM circulating cycle increased vanillylamine production to 14.89 g/L (125%)─the highest reported level in the current literature. Based on the biosynthesis of vanillylamine via the heterologous recombinant fatty acid pathway, capsaicin was synthesized de novo in yeast. We also revealed that protocatechuic acid can be produced from 3-dehydroshikimic acid by phenylalanine ammonium lyase or tyrosine ammonia lyase. In summary, this study provides a feasible strategy for developing yeast-based whole-cell factories for the eco-friendly synthesis of vanillylamine, which is a critical step toward capsaicin production in yeast.

Addition of solid-state fermentation product of yeast ameliorated the effects of high-fat diet on hepatic lipid metabolism, epidermal mucus, intestine and liver health, and gut microbiota of zebrafish

To assessed the effects of solid-state fermentation product of yeast (SFPY) supplementation on high-fat diet (HFD) induced challenges on growth, hepatic lipid metabolism, epidermal mucus, intestine and liver health and gut microbiota in zebrafish (Danio rerio), four experimental diets were prepared for one-month-old zebrafish: basal diet (Control), high-fat diet (HFD), 0.5% SFPY (0.5 SFPY) or 1.0% SFPY (1.0 SFPY)-added HFD. After 3 weeks of feeding, the results illustrated that although HFD increased weight gain (WG), corresponding decreased the feed conversation ratio (FCR), it caused negative influences including liver steatosis, intestinal and liver damage in zebrafish. Compared with HFD group, 1.0% SFPY obviously promoted the lysozyme activity and complement 4 (C4) level on epidermal mucus (P < 0.05), and significantly reduced liver TAG (P < 0.05). Addition of SFPY significantly decrease the lipid synthesis-related genes including C/EBPα, FAS, PPARγ, ACC1, DGAT2 and pro-inflammatory factors including IL-6, IL-1β in liver (P < 0.05), significantly increased the height of gut villi (P < 0.05). Moreover, the 1.0 SFPY group significantly reduced the abundance of gut microbiota concluding Proteobacteria, Fusobacteriota, Planctomycetota and improved the abundance of gut Actinobacteriota and Firmicutes (P < 0.05). To sum up, the addition of SFPY significantly ameliorated hepatic inflammation and intestinal damage caused by high-fat diet, and positively affected the intestinal microbiota composition of zebrafish.

Boosting the epoxidation of squalene to produce triterpenoids in Saccharomyces cerevisiae

BackgroundPolycyclic triterpenoids (PTs) are common in plants, and have attracted considerable interest due to their remarkable biological activities. Currently, engineering the ergosterol synthesis pathway in Saccharomyces cerevisiae is a safe and cost-competitive way to produce triterpenoids. However, the strict regulation of ERG1 involved in the epoxidation of squalene limits the triterpenoid production.ResultsIn this study, we found that the decrease in ERG7 protein level could dramatically boost the epoxidation of squalene by improving the protein stability of ERG1. We next explored the potential factors that affected the degradation process of ERG1 and confirmed that ERG7 was involved in the degradation process of ERG1. Subsequently, expression of four different triterpene cyclases utilizing either 2,3-oxidosqualene or 2,3:22,23-dioxidosqualene as the substrate in ERG7-degraded strains showed that the degradation of ERG7 to prompt the epoxidation of squalene could significantly increase triterpenoid production. To better display the potential of the strategy, we increased the supply of 2,3-oxidosqualene, optimized flux distribution between ergosterol synthesis pathway and β-amyrin synthesis pathway, and modified the GAL-regulation system to separate the growth stage from the production stage. The best-performing strain ultimately produced 4216.6 ± 68.4 mg/L of β-amyrin in a two-stage fed-fermentation (a 47-fold improvement over the initial strain).ConclusionsThis study showed that deregulation of the native restriction in ergosterol pathway was an effective strategy to increase triterpenoid production in yeast, which provided a new insight into triterpenoids biosynthesis.

Adaptive Laboratory Evolution Reveals the Selenium Efflux Process To Improve Selenium Tolerance Mediated by the Membrane Sulfite Pump in Saccharomyces cerevisiae.

Selenium (Se) is a micronutrient in most eukaryotes, and Se-enriched yeast is the most common selenium supplement. However, selenium metabolism and transport in yeast have remained unclear, greatly hindering the application of this element. To explore the latent selenium transport and metabolism mechanisms, we performed adaptive laboratory evolution under the selective pressure of sodium selenite and successfully obtained selenium-tolerant yeast strains. Mutations in the sulfite transporter gene ssu1 and its transcription factor gene fzf1 were found to be responsible for the tolerance generated in the evolved strains, and the selenium efflux process mediated by ssu1 was identified in this study. Moreover, we found that selenite is a competitive substrate for sulfite during the efflux process mediated by ssu1, and the expression of ssu1 is induced by selenite rather than sulfite. Based on the deletion of ssu1, we increased the intracellular selenomethionine content in Se-enriched yeast. This work confirms the existence of the selenium efflux process, and our findings may benefit the optimization of Se-enriched yeast production in the future. IMPORTANCE Selenium is an essential micronutrient for mammals, and its deficiency severely threatens human health. Yeast is the model organism for studying the biological role of selenium, and Se-enriched yeast is the most popular selenium supplement to solve Se deficiency. The cognition of selenium accumulation in yeast always focuses on the reduction process. Little is known about selenium transport, especially selenium efflux, which may play a crucial part in selenium metabolism. The significance of our research is in determining the selenium efflux process in Saccharomyces cerevisiae, which will greatly enhance our knowledge of selenium tolerance and transport, facilitating the production of Se-enriched yeast. Moreover, our research further advances the understanding of the relationship between selenium and sulfur in transport.

Application of Adaptive Laboratory Evolution in Lipid and Terpenoid Production in Yeast and Microalgae.

Due to the complexity of metabolic and regulatory networks in microorganisms, it is difficult to obtain robust phenotypes through artificial rational design and genetic perturbation. Adaptive laboratory evolution (ALE) engineering plays an important role in the construction of stable microbial cell factories by simulating the natural evolution process and rapidly obtaining strains with stable traits through screening. This review summarizes the application of ALE technology in microbial breeding, describes the commonly used methods for ALE, and highlights the important applications of ALE technology in the production of lipids and terpenoids in yeast and microalgae. Overall, ALE technology provides a powerful tool for the construction of microbial cell factories, and it has been widely used in improving the level of target product synthesis, expanding the range of substrate utilization, and enhancing the tolerance of chassis cells. In addition, in order to improve the production of target compounds, ALE also employs environmental or nutritional stress strategies corresponding to the characteristics of different terpenoids, lipids, and strains.