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1.
J Agric Food Chem ; 67(37): 10423-10431, 2019 Sep 18.
Artigo em Inglês | MEDLINE | ID: mdl-31487168

RESUMO

Plants often produce antifungal peptides and proteins in response to infection. Also wheat, which is the main ingredient of bread dough, contains such components. Here, we show that while some industrial strains of the baker's yeast Saccharomyces cerevisiae can efficiently ferment dough, some other strains show much lower fermentation capacities because they are sensitive to a specific wheat protein. We purified and identified what turned out to be a thaumatin-like protein through a combination of activity-guided fractionation, cation exchange chromatography, reversed-phase HPLC, and LC-MS/MS. Recombinant expression of the corresponding gene and testing the activity confirmed the inhibitory activity of the protein.


Assuntos
Proteínas de Plantas/química , Proteínas de Plantas/farmacologia , Saccharomyces cerevisiae/efeitos dos fármacos , Saccharomyces cerevisiae/crescimento & desenvolvimento , Triticum/química , Cromatografia Líquida , Fermentação , Proteínas de Plantas/isolamento & purificação , Proteínas de Plantas/metabolismo , Saccharomyces cerevisiae/metabolismo , Espectrometria de Massas em Tandem , Triticum/genética , Triticum/metabolismo , Triticum/microbiologia
2.
World J Microbiol Biotechnol ; 35(9): 136, 2019 Aug 20.
Artigo em Inglês | MEDLINE | ID: mdl-31432249

RESUMO

Volatile phenols such as 4-ethylphenol are produced from hydroxycinnamic acids by Dekkera bruxellensis, an important yeast contaminating alcoholic fermentations. 4-ethylphenol results from the decarboxylation and reduction of p-coumaric acid, a compound found in sugarcane musts. In wine, volatile phenols are responsible by sensorial alterations whereas in the context of bioethanol fermentation, little is known about their effects on the main yeast, Saccharomyces cerevisiae. Here we evaluated the interaction of 4-ethylphenol and pH, sucrose and ethanol on the growth and fermentation capacity of the industrial strain of S. cerevisiae PE-2. A central compound rotational design was utilized to evaluate the effect of 4-ethylphenol, pH, ethanol and sucrose concentration on the yeast maximum specific growth rate (µmax) in microplate experiments in YPS medium (Yeast extract-Peptone-Sucrose), at 30 °C. Following, single-cycle fermentations in YPS medium, pH 4.5, 17% sucrose, at 30 °C, with 4-ethylphenol in concentrations of 10 and 20 mg L-1 being added at the start or after 4 h of fermentation, were carried out. 4-ethylphenol affected µmax of S. cerevisiae in situations that resemble the conditions of industrial bioethanol production, especially the low pH of the fermentation medium and the high ethanol concentration because of the anaerobic sucrose uptake. The addition of 4-ethylphenol on fermentation resulted in significant effect on the cell yeast concentration, pH and alcohol production, with significant decrease from 86% to the range of 65-74% in the fermentative efficiency. The industrial yeast S. cerevisiae PE-2 growth and fermentative capacity were affected by the presence of 4-ethylphenol, a metabolite produced by D. bruxellensis, which may contribute to explain the impact of this yeast on bioethanol industrial production.


Assuntos
Etanol/metabolismo , Fermentação , Microbiologia Industrial , Fenóis/metabolismo , Saccharomyces cerevisiae/crescimento & desenvolvimento , Saccharomyces cerevisiae/metabolismo , Sacarose/metabolismo , Meios de Cultura/química , Inibidores do Crescimento/metabolismo , Concentração de Íons de Hidrogênio , Saccharomyces cerevisiae/efeitos dos fármacos , Temperatura Ambiente
3.
Vet Microbiol ; 235: 127-135, 2019 Aug.
Artigo em Inglês | MEDLINE | ID: mdl-31282370

RESUMO

Lawsonia intracellularis is an obligate intracellular Gram-negative bacterium that has been identified as the etiological agent of the contagious disease proliferative enteropathy (PE) in a wide range of animals, mainly pigs. The genome sequence of L. intracellularis indicates that this bacterium possess a type III secretion system (T3SS), which may assist the bacterium during cell invasion and host innate immune system evasion and could be a mechanism for inducing cellular proliferation. However, the effectors secreted by the T3SS (T3Es) of L. intracellularis have not been reported. T3Es often target conserved eukaryotic cellular processes, and yeast is an established and robust model system in which to reveal their function. By screening the growth inhibition of an ordered array of Saccharomyces cerevisiae strains expressing the hypothetical genes of L. intracellularis, LI1035 was identified as the first putative effector that inhibits yeast growth. The LI1035-induced growth inhibition was rescued in two of the 14 mitogen-activated protein kinase (MAPK) yeast haploid deletion strains, suggesting that LI1035 interacts with the components of the MAPK pathway in yeast. Phosphorylation assays confirmed that LI1035 inhibits MAPK signaling cascades in yeast and mammalian cells. Actin staining assays revealed that LI1035 regulates actin organization in yeast and mammalian cells. Taken together, these results indicate that LI1035 alters MAPK pathway activity and regulates actin organization in the host. These findings may contribute to the understanding the pathogenesis of L. intracellularis and support the use of yeast as a heterologous system for the functional analysis of pathogen-specific gene products in the laboratory.


Assuntos
Actinas/metabolismo , Proteínas de Bactérias/metabolismo , Lawsonia (Bactéria)/metabolismo , Proteínas Quinases Ativadas por Mitógeno/metabolismo , Saccharomyces cerevisiae/crescimento & desenvolvimento , Transdução de Sinais , Animais , Proteínas de Bactérias/genética , Proliferação de Células , Interações entre Hospedeiro e Microrganismos , Lawsonia (Bactéria)/genética , Fosforilação , Saccharomyces cerevisiae/genética , Sorbitol/farmacologia , Suínos , Temperatura Ambiente
4.
Int J Nanomedicine ; 14: 4801-4816, 2019.
Artigo em Inglês | MEDLINE | ID: mdl-31308659

RESUMO

Background: Silver nanoparticles (AgNPs) inhibit the proliferation of various fungi; however, their mechanisms of action remain poorly understood. To better understand the inhibitory mechanisms, we focused on the early events elicited by 5 nm AgNPs in pathogenic Candida albicans and non-pathogenic Saccharomyces cerevisiae. Methods: The effect of 5 nm and 100 nm AgNPs on fungus cell proliferation was analyzed by growth kinetics monitoring and spot assay. We examined cell cycle progression, reactive oxygen species (ROS) production, and cell death using flow cytometry. Glucose uptake was assessed using tritium-labeled 2-deoxyglucose. Results: The growth of both C. albicans and S. cerevisiae was suppressed by treatment with 5 nm AgNPs but not with 100 nm AgNPs. In addition, 5 nm AgNPs induced cell cycle arrest and a reduction in glucose uptake in both fungi after 30 minutes of culture in a dose-dependent manner (P<0.05). However, in C. albicans only, an increase in ROS production was detected after exposure to 5 nm AgNPs. Concordantly, an ROS scavenger blocked the effect of 5 nm AgNPs on the cell cycle and glucose uptake in C. albicans only. Furthermore, the growth-inhibition effect of 5 nm AgNPs was not greater in S. cerevisiae mutant strains deficient in oxidative stress response genes than it was in wild type. Finally, 5 nm AgNPs together with a glycolysis inhibitor, 3-bromopyruvate, synergistically enhanced cell death in C. albicans (P<0.05) but not in S. cerevisiae. Conclusion: AgNPs exhibit antifungal activity in a manner that may or may not be ROS dependent, according to the fungal species. The combination of AgNPs with 3-bromopyruvate may be more useful against infection with C. albicans.


Assuntos
Candida albicans/citologia , Ciclo Celular/efeitos dos fármacos , Nanopartículas Metálicas/toxicidade , Piruvatos/farmacologia , Espécies Reativas de Oxigênio/metabolismo , Saccharomyces cerevisiae/citologia , Prata/farmacologia , Antifúngicos/farmacologia , Candida albicans/efeitos dos fármacos , Candida albicans/crescimento & desenvolvimento , Morte Celular/efeitos dos fármacos , Proliferação de Células/efeitos dos fármacos , Parede Celular/efeitos dos fármacos , Parede Celular/genética , Depuradores de Radicais Livres/farmacologia , Fase G1/efeitos dos fármacos , Genes Fúngicos , Glucose/metabolismo , Glicólise/efeitos dos fármacos , Testes de Sensibilidade Microbiana , Mitocôndrias/efeitos dos fármacos , Mitocôndrias/metabolismo , Estresse Oxidativo/efeitos dos fármacos , Estresse Oxidativo/genética , Saccharomyces cerevisiae/efeitos dos fármacos , Saccharomyces cerevisiae/genética , Saccharomyces cerevisiae/crescimento & desenvolvimento
5.
Int J Food Microbiol ; 304: 75-88, 2019 Sep 02.
Artigo em Inglês | MEDLINE | ID: mdl-31174038

RESUMO

Fermented cereal doughs constitute a predominant part of West African diets. The environment of fermented doughs can be hostile for microbial survival due to high levels of microbial metabolites such as weak carboxylic organic acids and ethanol. In order to get a better understanding of the intrinsic factors affecting the microbial successions of yeasts during dough fermentation, survival and physiological responses of the yeasts associated with West African fermented cereal doughs were investigated at exposure to relevant concentrations of microbial inhibitory compounds. Three strains each of the predominant species, i.e. Saccharomyces cerevisiae, Kluyveromyces marxianus, Pichia kudriavzevii as well as the opportunistic pathogen Candida glabrata were studied. The strains were exposed to individual stress factors of cereal doughs, i.e. (i) pH 3.4, (ii) 3% (v/v) ethanol (EtOHpH3.4), (iii) 285 mM lactic acid (LApH3.4) and (iv) 150 mM acetic acid (AApH3.4) as well as to combinations of these stress factors, i.e. (v) (LA + AA)pH 3.4 and (vi) (LA + AA+EtOH)pH 3.4. Growth and single cell viability were studied by flow cytometry using combined SYTO 13 and propidium iodide (PI) staining. Intracellular pH (pHi), plasma membrane integrity and micro-colony development of stressed cells were studied by fluorescence microscopy using PI and carboxyfluorescein diacetate succinimidyl ester (CFDA-se). Viability of the yeast strains was not affected by pH 3.4 and 3% (v/v) ethanol (EtOHpH3.4). 285 mM lactic acid (LApH3.4) reduced the specific growth rate (µmax) from 0.27-0.41 h-1 to 0.11-0.26 h-1 and the viability from 100% to 2.6-41.7% at 72 h of exposure in most yeast strains, except for two strains of C. glabrata. 150 mM acetic acid (AApH3.4) as well as the combinations (LA + AA)pH 3.4 and (LA + AA+EtOH)pH 3.4 reduced µmax to 0.0 h-1 and induced significant cell death for all the yeast strains. Exposed to (LA + AA+EtOH)pH 3.4, the most resistant yeast strains belonged to S. cerevisiae followed by P. kudriavzevii, whereas C. glabrata and K. marxianus were more sensitive. Strain variations were observed within all four species. When transferred to non-stress conditions, i.e. MYGP, pH 5.6, after exposure to (LA + AA+EtOH)pH 3.4 for 6 h, 45% of the single cells of the most resistant S. cerevisiae strain kept their plasma membrane integrity, recovered their pHi to near physiological range (pHi = 6.1-7.4) and resumed proliferation after 3-24 h of lag phase. The results obtained are valuable in order to change processing conditions of the dough to favor the survival of preferable yeast species, i.e. S. cerevisiae and K. marxianus and inhibit opportunistic pathogen yeast species as C. glabrata.


Assuntos
Candida/efeitos dos fármacos , Grão Comestível/microbiologia , Alimentos Fermentados/microbiologia , Kluyveromyces/efeitos dos fármacos , Viabilidade Microbiana/efeitos dos fármacos , Pichia/efeitos dos fármacos , Saccharomyces cerevisiae/efeitos dos fármacos , Ácido Acético/farmacologia , Reatores Biológicos , Candida/crescimento & desenvolvimento , Candida/isolamento & purificação , Etanol/farmacologia , Fermentação , Kluyveromyces/crescimento & desenvolvimento , Kluyveromyces/isolamento & purificação , Ácido Láctico/farmacologia , Pichia/crescimento & desenvolvimento , Pichia/isolamento & purificação , Saccharomyces cerevisiae/crescimento & desenvolvimento , Saccharomyces cerevisiae/isolamento & purificação , Fermento Seco , Leveduras/isolamento & purificação
6.
J Microbiol Biotechnol ; 29(6): 905-912, 2019 Jun 28.
Artigo em Inglês | MEDLINE | ID: mdl-31154746

RESUMO

Bioethanol has attracted much attention in recent decades as a sustainable and environmentally friendly alternative energy source. In this study, we compared the production of bioethanol by Candida molischiana and Saccharomyces cerevisiae at different initial concentrations of cellobiose and glucose. The results showed that C. molischiana can utilize both glucose and cellobiose, whereas S. cerevisiae can only utilize glucose. The ethanol yields were 43-51% from different initial concentrations of carbon source. In addition, different concentrations of microcrystalline cellulose (Avicel) were directly converted to ethanol by a combination of Trichoderma reesei and two yeasts. Cellulose was first hydrolyzed by a fully enzymatic saccharification process using T. reesei cellulases, and the reducing sugars and glucose produced during the process were further used as carbon source for bioethanol production by C. molischiana or S. cerevisiae. Sequential culture of T. reesei and two yeasts revealed that C. molischiana was more efficient for bioconversion of sugars to ethanol than S. cerevisiae. When 20 g/l Avicel was used as a carbon source, the maximum reducing sugar, glucose, and ethanol yields were 42%, 26%, and 20%, respectively. The maximum concentrations of reducing sugar, glucose, and ethanol were 10.9, 8.57, and 5.95 g/l, respectively, at 120 h by the combination of T. reesei and C. molischiana from 50 g/l Avicel.


Assuntos
Biocombustíveis , Candida/metabolismo , Celobiose/metabolismo , Celulose/metabolismo , Etanol/metabolismo , Glucose/metabolismo , Saccharomyces cerevisiae/metabolismo , Candida/crescimento & desenvolvimento , Celobiose/química , Celulase/metabolismo , Celulose/química , Proteínas Fúngicas/metabolismo , Glucose/química , Hidrólise , Saccharomyces cerevisiae/crescimento & desenvolvimento , Açúcares/metabolismo , Trichoderma/crescimento & desenvolvimento , Trichoderma/metabolismo
7.
Microb Cell Fact ; 18(1): 88, 2019 May 23.
Artigo em Inglês | MEDLINE | ID: mdl-31122246

RESUMO

BACKGROUND: There have been many successful strategies to implement xylose metabolism in Saccharomyces cerevisiae, but no effort has so far enabled xylose utilization at rates comparable to that of glucose (the preferred sugar of this yeast). Many studies have pointed towards the engineered yeast not sensing that xylose is a fermentable carbon source despite growing and fermenting on it, which is paradoxical. We have previously used fluorescent biosensor strains to in vivo monitor the sugar signalome in yeast engineered with xylose reductase and xylitol dehydrogenase (XR/XDH) and have established that S. cerevisiae senses high concentrations of xylose with the same signal as low concentration of glucose, which may explain the poor utilization. RESULTS: In the present study, we evaluated the effects of three deletions (ira2∆, isu1∆ and hog1∆) that have recently been shown to display epistatic effects on a xylose isomerase (XI) strain. Through aerobic and anaerobic characterization, we showed that the proposed effects in XI strains were for the most part also applicable in the XR/XDH background. The ira2∆isu1∆ double deletion led to strains with the highest specific xylose consumption- and ethanol production rates but also the lowest biomass titre. The signalling response revealed that ira2∆isu1∆ changed the low glucose-signal in the background strain to a simultaneous signalling of high and low glucose, suggesting that engineering of the signalome can improve xylose utilization. CONCLUSIONS: The study was able to correlate the previously proposed beneficial effects of ira2∆, isu1∆ and hog1∆ on S. cerevisiae xylose uptake, with a change in the sugar signalome. This is in line with our previous hypothesis that the key to resolve the xylose paradox lies in the sugar sensing and signalling networks. These results indicate that the future engineering targets for improved xylose utilization should probably be sought not in the metabolic networks, but in the signalling ones.


Assuntos
Glucose , Redes e Vias Metabólicas/genética , Saccharomyces cerevisiae , Xilose , Transporte Biológico , Fermentação , Deleção de Genes , Glucose/genética , Glucose/metabolismo , Proteínas Mitocondriais/genética , Proteínas Mitocondriais/metabolismo , Plasmídeos , Saccharomyces cerevisiae/genética , Saccharomyces cerevisiae/crescimento & desenvolvimento , Saccharomyces cerevisiae/metabolismo , Proteínas de Saccharomyces cerevisiae/genética , Proteínas de Saccharomyces cerevisiae/metabolismo , Transdução de Sinais , Xilose/genética , Xilose/metabolismo
8.
Sensors (Basel) ; 19(9)2019 Apr 30.
Artigo em Inglês | MEDLINE | ID: mdl-31052151

RESUMO

The odor information produced in Saccharomyces cerevisiae culture is one of the important characteristics of yeast growth status. This work innovatively presents the quantitative monitoring of cell concentration during the yeast culture process using a homemade color sensor. First, a color sensor array, which could visually represent the odor changes produced during the yeast culture process, was developed using eleven porphyrins and one pH indicator. Second, odor information of the culture substrate was obtained during the process using the homemade color sensor. Next, color components, which came from different color sensitive spots, were extracted first and then optimized using the ant colony optimization (ACO) algorithm. Finally, the back propagation neural network (BPNN) model was developed using the optimized feature color components for quantitative monitoring of cell concentration. Results demonstrated that BPNN models, which were developed using two color components from FTPPFeCl (component B) and MTPPTE (component B), can obtain better results on the basis of both the comprehensive consideration of the model performance and the economic benefit. In the validation set, the average of determination coefficient R P 2 was 0.8837 and the variance was 0.0725, while the average of root mean square error of prediction (RMSEP) was 1.0033 and the variance was 0.1452. The overall results sufficiently demonstrate that the optimized sensor array can satisfy the monitoring accuracy and stability of the cell concentration in the process of yeast culture.


Assuntos
Técnicas Biossensoriais , Técnicas de Cultura de Células , Rastreamento de Células , Saccharomyces cerevisiae/isolamento & purificação , Algoritmos , Cor , Concentração de Íons de Hidrogênio , Redes Neurais (Computação) , Porfirinas/química , Saccharomyces cerevisiae/crescimento & desenvolvimento
9.
Molecules ; 24(9)2019 May 07.
Artigo em Inglês | MEDLINE | ID: mdl-31067673

RESUMO

Flor velum yeast growth activators during biological aging are currently unknown. In this sense, this research focuses on the use of bee pollen as a flor velum activator. Bee pollen influence on viable yeast development, surface hydrophobicity, and yeast assimilable nitrogen has already been studied. Additionally, bee pollen effects on the main compounds related to flor yeast metabolism and wine sensory characteristics have been evaluated. "Fino" (Sherry) wine was supplemented with bee pollen using six different doses ranging from 0.1 to 20 g/L. Its addition in a dose equal or greater than 0.25 g/L can be an effective flor velum activator, increasing yeast populations and its buoyancy due to its content of yeast assimilable nitrogen and fatty acids. Except for the 20 g/L dose, pollen did not induce any significant effect on flor velum metabolism, physicochemical parameters, organic acids, major volatile compounds, or glycerol. Sensory analysis showed that low bee pollen doses increase wine's biological aging attributes, obtaining the highest score from the tasting panel. Multiflora bee pollen could be a natural oenological tool to enhance flor velum development and wine sensory qualities. This study confirms association between the bee pollen dose applied and the flor velum growth rate. The addition of bee pollen could help winemakers to accelerate or reimplant flor velum in biologically aged wines.


Assuntos
Abelhas/química , Pólen/química , Saccharomyces cerevisiae/crescimento & desenvolvimento , Vinho/microbiologia , Animais , Ácidos Graxos/química , Ácidos Graxos/metabolismo , Fermentação , Nitrogênio/química , Saccharomyces cerevisiae/efeitos dos fármacos , Saccharomyces cerevisiae/metabolismo
10.
Food Chem ; 292: 90-97, 2019 Sep 15.
Artigo em Inglês | MEDLINE | ID: mdl-31054697

RESUMO

Ethyl carbamate (EC) is a potentially carcinogenic substance present in most alcoholic beverages, especially in Chinese rice wine. Consequently, much effort has been directed at suppressing EC formation during the production of these beverages, with particular attention directed at the use of urethanase, as this enzyme can directly catalyze EC degradation. Herein, we investigated the ability of three lactic acid bacteria (Oenococcus oeni, Lactobacillus brevis, and Lactobacillus plantarum) to generate urethanase during co-cultivation with Saccharomyces cerevisiae. qPCR and transcriptomic analyses revealed that 57 genes of S. cerevisiae were significantly expressed in the presence of L. brevis, which highlighted the importance of studying urethanase-promoted EC degradation for establishing a powerful technique of EC level control. The obtained results provided deep insights into the adaptive responses of S. cerevisiae to the challenging environment of mixed-culture fermentation.


Assuntos
Lactobacillus/crescimento & desenvolvimento , Saccharomyces cerevisiae/genética , Uretana/metabolismo , Vinho/análise , Amidoidrolases/genética , Amidoidrolases/metabolismo , Fermentação , Proteínas Fúngicas/genética , Proteínas Fúngicas/metabolismo , Perfilação da Expressão Gênica , Oenococcus/crescimento & desenvolvimento , Saccharomyces cerevisiae/crescimento & desenvolvimento , Saccharomyces cerevisiae/metabolismo
11.
Environ Sci Pollut Res Int ; 26(17): 16952-16973, 2019 Jun.
Artigo em Inglês | MEDLINE | ID: mdl-31030399

RESUMO

Oleaginous microalgae and yeast are the two major propitious factories which are sustainable sources for biodiesel production, as they can accumulate high quantities of lipids inside their bodies. To date, various microalgal and yeast species have been exploited singly for biodiesel production. However, despite the ongoing efforts, their low lipid productivity and the high cost of cultivation are still the major bottlenecks hindering their large-scale deployment. Co-culturing of microalgae and yeast has the potential to increase the overall lipid productivity by minimizing its production cost as both these organisms can utilize each other's by-products. Microalgae act as an O2 generator for yeast while consuming the CO2 and organic acids released by the yeast cells. Further, yeast can break complex sugars in the medium, which can then be utilized by microalgae thereby opening new options for copious and low-cost feedstocks such as agricultural residues. The current review provides a historical and technical overview of the existing studies on co-culturing of yeast and microalgae and elucidates the crucial factors that affect the symbiotic relationship between these two organisms. Furthermore, the review also highlighted the advantages and the future perspectives for paving a path towards a sustainable biodiesel product.


Assuntos
Biocombustíveis/análise , Metabolismo dos Lipídeos , Microalgas/metabolismo , Saccharomyces cerevisiae/metabolismo , Biomassa , Técnicas de Cocultura , Microalgas/crescimento & desenvolvimento , Saccharomyces cerevisiae/crescimento & desenvolvimento
12.
Lett Appl Microbiol ; 69(1): 50-56, 2019 Jul.
Artigo em Inglês | MEDLINE | ID: mdl-31004511

RESUMO

Bioethanol fermentation is continuously exposed to contamination by Lactic Acid Bacteria (LAB). In this study, the effect of adding nisin (250 mg l-1 ) to the acid wash on the viability of five bacterial contaminants were evaluated both alone and in co-incubation with Saccharomyces cerevisiae. Additionally, fed-batch fermentation was performed using an acid or acid/nisin wash for S. cerevisiae alone and cocultured with the LAB strains. Parameters such as ethanol production, sugar consumption and lactic acid production were monitored. Four model LAB were more susceptible to the acid/nisin wash than the acid wash, and were most susceptible when incubated with yeast. A fifth model LAB was very sensitive to both treatments regardless of the presence of yeast. The addition of nisin to the acid wash lowered the required time for adequate washing and resulted in a higher ethanol production (54·5 ± 0·1 g l-1 ) than the acid wash alone (52·6 ± 0·1 g l-1 ) in a subsequent fermentation. These results indicate the potential benefits of supplementing with nisin to improve the acid wash step of bioethanol fermentations. SIGNIFICANCE AND IMPACT OF THE STUDY: Acid washing by the bioethanol fermentation industry reduces yeast efficiency and selects for contaminant bacteria that are resistant to acid treatments. This study demonstrates that the incorporation of nisin into the acid wash step results in a more potent removal of lactic acid bacteria while significantly shortening the length of time needed for the acid wash.


Assuntos
Antibacterianos/farmacologia , Etanol/metabolismo , Ácido Láctico/metabolismo , Lactobacillus/metabolismo , Nisina/farmacologia , Saccharomyces cerevisiae/metabolismo , Saccharum/metabolismo , Técnicas de Cocultura , Fermentação , Lactobacillus/efeitos dos fármacos , Lactobacillus/crescimento & desenvolvimento , Saccharomyces cerevisiae/crescimento & desenvolvimento
13.
Molecules ; 24(8)2019 Apr 15.
Artigo em Inglês | MEDLINE | ID: mdl-30991698

RESUMO

Due to the increase of the use of yeast derivatives (YDs) in winemaking to improve the technological and sensory properties in wines, in this work we evaluated the effect of the post-fermentation application of different yeast derivative products on the physical and chemical properties and astringency of red wines during two consecutive harvests. A commercial and two experimental new yeast derivatives were applied at a medium‒high dosage (30 g/hL). The addition of different yeast derivatives in red wine increased the concentration of different polysaccharide fractions and, therefore, the total polysaccharide content, producing a decrease in the duration of the wine astringency perception over time. The use of yeast derivatives could produce an adsorption/clarification and/or protective effect on the phenolic compounds. However, it did not produce an important modification of the colour parameters. An intensification or a lower decrease of the most volatile compound groups was produced, but it depended on the YDs and yeast strain used in fermentation and post-fermentation processes.


Assuntos
Fenóis/análise , Polissacarídeos/análise , Saccharomyces cerevisiae/crescimento & desenvolvimento , Compostos Orgânicos Voláteis/análise , Vinho/análise
14.
Appl Microbiol Biotechnol ; 103(11): 4325-4336, 2019 Jun.
Artigo em Inglês | MEDLINE | ID: mdl-31020380

RESUMO

Aromatic amino acid metabolism in yeast is an important source of secondary compounds that influence the aroma and flavour of alcoholic beverages and foods. Examples are the higher alcohol 2-phenylethanol, and its acetate ester, 2-phenylethyl acetate, which impart desirable floral aromas in wine, beer and baker's products. Beyond this well-known influence on the organoleptic properties of alcoholic beverages and foods, there is a growing interest in understanding and modulating yeast aromatic amino acid metabolism. The tryptophan derivatives melatonin and serotonin have bioactive properties and exert positive effects on human health, and aromatic amino acids are also the precursors of products of industrial interest, such as nutraceuticals, fragrances, and opium-derived drugs. This mini-review presents current knowledge on the formation of compounds from aromatic amino acids by Saccharomyces cerevisiae, from genetic and environmental influences on their flavour impacts in alcoholic beverages to their potential as bioactive compounds, and the use of yeast as microbial factories for the production of commercially relevant aromatic compounds.


Assuntos
Bebidas Alcoólicas/microbiologia , Aminoácidos Aromáticos/metabolismo , Aromatizantes/metabolismo , Indústria Alimentícia/métodos , Saccharomyces cerevisiae/metabolismo , Compostos Orgânicos Voláteis/metabolismo , Saccharomyces cerevisiae/crescimento & desenvolvimento
15.
J Agric Food Chem ; 67(19): 5596-5606, 2019 May 15.
Artigo em Inglês | MEDLINE | ID: mdl-30957490

RESUMO

Kaempferol is a polyphenolic compound with various reported health benefits and thus harbors considerable potential for food-engineering applications. In this study, a high-yield kaempferol-producing cell factory was constructed by multiple strategies, including gene screening, elimination of the phenylethanol biosynthetic branch, optimizing the core flavonoid synthetic pathway, supplementation of precursor PEP/E4P, and mitochondrial engineering of F3H and FLS. A total of 86 mg/L of kaempferol was achieved in strain YL-4, to date the highest production titer in yeast. Furthermore, a coculture system and supplementation of surfactants were investigated, to relieve the metabolic burden as well as the low solubility/possible transport limitations of flavonoids, respectively. In the coculture system, the whole pathway was divided across two strains, resulting in 50% increased cell growth. Meanwhile, supplementation of Tween 80 in our engineered strains yielded 220 mg/L of naringenin and 200 mg/L of mixed flavonoids-among the highest production titer reported via de novo production in yeast.


Assuntos
Quempferóis/biossíntese , Saccharomyces cerevisiae/genética , Saccharomyces cerevisiae/metabolismo , Engenharia Metabólica , Mitocôndrias/genética , Mitocôndrias/metabolismo , Saccharomyces cerevisiae/crescimento & desenvolvimento , Proteínas de Saccharomyces cerevisiae/genética , Proteínas de Saccharomyces cerevisiae/metabolismo
16.
Int J Food Microbiol ; 300: 43-52, 2019 Jul 02.
Artigo em Inglês | MEDLINE | ID: mdl-31035250

RESUMO

The spoilage of foods caused by the growth of undesirable yeast species is a problem in the food industry. Yeast species such as Zygosaccharomyces bailii, Zygosaccharomyces rouxii, Debaryomyces hansenii, Kluyveromyces lactis and Saccharomyces cerevisiae have been encountered in foods such as high sugar products, fruit juices, wine, mayonnaise, chocolate and soft drinks. The demand for new methods of preservations has increased because of the negative association attached to chemical preservatives. The sequence of a novel short peptide (KKFFRAWWAPRFLK-NH2) was modified to generate three versions of this original peptide. These peptides were tested for the inhibition of the yeasts mentioned above, allowing for the better understanding of their residue modifications. The range of the minimum inhibitory concentration was between 25 and 200 µg/mL. Zygosaccharomyces bailii was the most sensitive strain to the peptides, while Zygosaccharomyces rouxii was the most resistant. Membrane permeabilisation was found to be responsible for yeast inhibition at a level which was a two-fold increase of the MIC (400 µg/mL). The possibility of the production of reactive oxygen species was also assessed but was not recognised as a factor involved for the peptides' mode of action. Their stability in different environments was also tested, focusing on high salt, pH and thermal stability. The newly designed peptides showed good antifungal activity against some common food spoilage yeasts and has been proven effective in the application in Fanta Orange. These efficient novel peptides represent a new source of food preservation that can be used as an alternative for current controversial preservatives used in the food industry.


Assuntos
Microbiologia de Alimentos/métodos , Conservantes de Alimentos/farmacologia , Peptídeos/farmacologia , Leveduras/efeitos dos fármacos , Antifúngicos/farmacologia , Indústria de Processamento de Alimentos , Sucos de Frutas e Vegetais/microbiologia , Kluyveromyces/efeitos dos fármacos , Kluyveromyces/crescimento & desenvolvimento , Testes de Sensibilidade Microbiana , Saccharomyces cerevisiae/efeitos dos fármacos , Saccharomyces cerevisiae/crescimento & desenvolvimento , Leveduras/crescimento & desenvolvimento , Zygosaccharomyces/crescimento & desenvolvimento
17.
J Sci Food Agric ; 99(9): 4439-4444, 2019 Jul.
Artigo em Inglês | MEDLINE | ID: mdl-30866050

RESUMO

BACKGROUND: Today, there is an increasing concern about the consumption of synthetic colorants in food because of their possible health hazards. Monascus purpureus has attracted a great deal of attention as it produces various coloured pigments with high chemical stability, but it also produces citrinin, a secondary toxic metabolite, along with the pigments. This study aims to investigate the amount of pigment and citrinin reduction by different treatments with Saccharomyces cerevisiae such as heat treatment and suspension concentration. RESULTS: The results indicated that the ability of S. cerevisiae regarding citrinin adsorption increased with increase of temperature and yeast concentration. The maximum extent of citrinin adsorption was related to heat treatment at 121 °C and a yeast concentration of 105 cells mL-1 , for which citrinin reduced from 4.43 mg L-1 in control to 0.1 mg L-1 . Heat treatment of 103 cells mL-1 suspension of S. cerevisiae cells at 50 °C, with 0.56 mg L-1 citrinin remaining in the medium, showed the lowest ability for citrinin binding. The optimum absorbance of all red, orange and yellow pigments was observed for the heat treatment at 50 °C and yeast concentrations of 103 and 104 cells mL-1 which was greater than that for the control. CONCLUSIONS: We can conclude from this study that heat treatment with S. cerevisiae can be a useful way to reduce citrinin to below the standard limits. © 2019 Society of Chemical Industry.


Assuntos
Citrinina/metabolismo , Monascus/metabolismo , Pigmentos Biológicos/metabolismo , Saccharomyces cerevisiae/metabolismo , Citrinina/toxicidade , Temperatura Alta , Concentração de Íons de Hidrogênio , Saccharomyces cerevisiae/química , Saccharomyces cerevisiae/crescimento & desenvolvimento
18.
Microb Cell Fact ; 18(1): 50, 2019 Mar 11.
Artigo em Inglês | MEDLINE | ID: mdl-30857529

RESUMO

BACKGROUND: The physiological characterization of microorganisms provides valuable information for bioprocess development. Chemostat cultivations are a powerful tool for this purpose, as they allow defined changes to one single parameter at a time, which is most commonly the growth rate. The subsequent establishment of a steady state then permits constant variables enabling the acquisition of reproducible data sets for comparing microbial performance under different conditions. We performed physiological characterizations of a 3-hydroxypropionic acid (3-HP) producing Saccharomyces cerevisiae strain in a miniaturized and parallelized chemostat cultivation system. The physiological conditions under investigation were various growth rates controlled by different nutrient limitations (C, N, P). Based on the cultivation parameters obtained subsequent fed-batch cultivations were designed. RESULTS: We report technical advancements of a small-scale chemostat cultivation system and its applicability for reliable strain screening under different physiological conditions, i.e. varying dilution rates and different substrate limitations (C, N, P). Exploring the performance of an engineered 3-HP producing S. cerevisiae strain under carbon-limiting conditions revealed the highest 3-HP yields per substrate and biomass of 16.6 %C-mol and 0.43 g gCDW-1, respectively, at the lowest set dilution rate of 0.04 h-1. 3-HP production was further optimized by applying N- and P-limiting conditions, which resulted in a further increase in 3-HP yields revealing values of 21.1 %C-mol and 0.50 g gCDW-1 under phosphate-limiting conditions. The corresponding parameters favoring an increased 3-HP production, i.e. dilution rate as well as C- and P-limiting conditions, were transferred from the small-scale chemostat cultivation system to 1-L bench-top fermenters operating in fed-batch conditions, revealing 3-HP yields of 15.9 %C-mol and 0.45 g gCDW-1 under C-limiting, as well as 25.6 %C-mol and 0.50 g gCDW-1 under phosphate-limiting conditions. CONCLUSIONS: Small-scale chemostat cultures are well suited for the physiological characterization of microorganisms, particularly for investigating the effect of changing cultivation parameters on microbial performance. In our study, optimal conditions for 3-HP production comprised (i) a low dilution rate of 0.04 h-1 under carbon-limiting conditions and (ii) the use of phosphate-limiting conditions. Similar 3-HP yields were achieved in chemostat and fed-batch cultures under both C- and P-limiting conditions proving the growth rate as robust parameter for process transfer and thus the small-scale chemostat system as powerful tool for process optimization.


Assuntos
Técnicas de Cultura Celular por Lotes/métodos , Ácido Láctico/análogos & derivados , Saccharomyces cerevisiae/metabolismo , Biomassa , Reatores Biológicos , Carbono/metabolismo , Meios de Cultura , Fermentação , Ácido Láctico/biossíntese , Saccharomyces cerevisiae/crescimento & desenvolvimento
19.
Braz J Microbiol ; 50(2): 379-388, 2019 Apr.
Artigo em Inglês | MEDLINE | ID: mdl-30826999

RESUMO

The Asparagaceae family is endemic from America, being the Agave genus the most important. The Agave species possess economic relevance and are use as raw material to produce several distilled alcoholic beverages, as bacanora, tequila, and mezcal. The fermentation process has been carry out either spontaneously or by adding a selected yeast strain. The latter is generally responsible for the production of ethanol and volatile compounds. This study comprised five Agave species (A. angustifolia, A. cupreata, A. durangensis, A. salmiana, and A. tequilana) and eight endogenous yeast strains: five of them were non-Saccharomyces (Torulaspora delbrueckii, Zygosaccharomyces bisporus, Candida ethanolica, and two Kluyveromyces marxianus) and three Saccharomyces cerevisiae strains. The results showed that the S. cerevisiae strains were not able to grow on A. durangensis and A. salmiana juices. The Kluyveromyces marxianus strains grew and fermented all the agave juices and displayed high ethanol production (48-52 g L-1) and volatile compounds. The ethanol production was higher on A. angustifolia juice (1.1-2.8-fold), whereas the volatile compound was dependent on both yeast strain and the Agave species. The use of endogenous non-Saccharomyces yeast strains is feasible, as they may outperform S. cerevisiae regarding the production of fermented beverages from agave plants with a high content of ethanol and aromatic compounds. Graphical abstract.


Assuntos
Agave/microbiologia , Bebidas Alcoólicas/microbiologia , Candida/metabolismo , Kluyveromyces/metabolismo , Saccharomyces cerevisiae/metabolismo , Torulaspora/metabolismo , Zygosaccharomyces/metabolismo , Candida/crescimento & desenvolvimento , Etanol/metabolismo , Fermentação/fisiologia , Kluyveromyces/crescimento & desenvolvimento , Saccharomyces cerevisiae/crescimento & desenvolvimento , Torulaspora/crescimento & desenvolvimento , Zygosaccharomyces/crescimento & desenvolvimento
20.
PLoS Genet ; 15(3): e1008037, 2019 03.
Artigo em Inglês | MEDLINE | ID: mdl-30856163

RESUMO

Microbes can be metabolically engineered to produce biofuels and biochemicals, but rerouting metabolic flux toward products is a major hurdle without a systems-level understanding of how cellular flux is controlled. To understand flux rerouting, we investigated a panel of Saccharomyces cerevisiae strains with progressive improvements in anaerobic fermentation of xylose, a sugar abundant in sustainable plant biomass used for biofuel production. We combined comparative transcriptomics, proteomics, and phosphoproteomics with network analysis to understand the physiology of improved anaerobic xylose fermentation. Our results show that upstream regulatory changes produce a suite of physiological effects that collectively impact the phenotype. Evolved strains show an unusual co-activation of Protein Kinase A (PKA) and Snf1, thus combining responses seen during feast on glucose and famine on non-preferred sugars. Surprisingly, these regulatory changes were required to mount the hypoxic response when cells were grown on xylose, revealing a previously unknown connection between sugar source and anaerobic response. Network analysis identified several downstream transcription factors that play a significant, but on their own minor, role in anaerobic xylose fermentation, consistent with the combinatorial effects of small-impact changes. We also discovered that different routes of PKA activation produce distinct phenotypes: deletion of the RAS/PKA inhibitor IRA2 promotes xylose growth and metabolism, whereas deletion of PKA inhibitor BCY1 decouples growth from metabolism to enable robust fermentation without division. Comparing phosphoproteomic changes across ira2Δ and bcy1Δ strains implicated regulatory changes linked to xylose-dependent growth versus metabolism. Together, our results present a picture of the metabolic logic behind anaerobic xylose flux and suggest that widespread cellular remodeling, rather than individual metabolic changes, is an important goal for metabolic engineering.


Assuntos
Saccharomyces cerevisiae/metabolismo , Xilose/metabolismo , Anaerobiose , Biocombustíveis , Biomassa , Proteínas Quinases Dependentes de AMP Cíclico/genética , Proteínas Quinases Dependentes de AMP Cíclico/metabolismo , Evolução Molecular Direcionada , Fermentação , Perfilação da Expressão Gênica , Genes Fúngicos , Glucose/metabolismo , Proteínas de Membrana/genética , Proteínas de Membrana/metabolismo , Engenharia Metabólica , Redes e Vias Metabólicas , Modelos Biológicos , Mutação , Fosforilação , Proteínas Serina-Treonina Quinases/genética , Proteínas Serina-Treonina Quinases/metabolismo , Proteoma/metabolismo , Saccharomyces cerevisiae/genética , Saccharomyces cerevisiae/crescimento & desenvolvimento , Proteínas de Saccharomyces cerevisiae/genética , Proteínas de Saccharomyces cerevisiae/metabolismo , Biologia de Sistemas , Fatores de Transcrição/genética , Fatores de Transcrição/metabolismo
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