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1.
Sci Rep ; 10(1): 16314, 2020 10 01.
Artigo em Inglês | MEDLINE | ID: mdl-33004914

RESUMO

Lachancea kluyveri, a weak Crabtree positive yeast, has been extensively studied for its unique URC pyrimidine catabolism pathway. It produces more biomass than Saccharomyces cerevisiae due to the underlying weak Crabtree effect and resorts to fermentation only in oxygen limiting conditions that renders it as a suitable industrial host. The yeast also produces ethyl acetate as a major overflow metabolite in aerobic conditions. Here, we report the first genome-scale metabolic model, iPN730, of L. kluyveri comprising of 1235 reactions, 1179 metabolites, and 730 genes distributed in 8 compartments. The in silico viability in different media conditions and the growth characteristics in various carbon sources show good agreement with experimental data. Dynamic flux balance analysis describes the growth dynamics, substrate utilization and product formation kinetics in various oxygen-limited conditions. We have also demonstrated the effect of switching carbon sources on the production of ethyl acetate under varying oxygen uptake rates. A phenotypic phase plane analysis described the energetic cost penalty of ethyl acetate and ethanol production on the specific growth rate of L. kluyveri. We generated the context specific models of L. kluyveri growing on uracil or ammonium salts as the sole nitrogen source. Differential flux calculated using flux variability analysis helped us in highlighting pathways like purine, histidine, riboflavin and pyrimidine metabolism associated with uracil degradation. The genome-scale metabolic construction of L. kluyveri will provide a better understanding of metabolism behind ethyl acetate production as well as uracil catabolism (pyrimidine degradation) pathway. iPN730 is an addition to genome-scale metabolic models of non-conventional yeasts that will facilitate system-wide omics analysis to understand fungal metabolic diversity.


Assuntos
Genoma Fúngico/genética , Saccharomycetales/genética , Acetatos/metabolismo , Simulação por Computador , Metabolismo Energético , Etanol/metabolismo , Genes Fúngicos/genética , Redes e Vias Metabólicas/genética , Modelos Biológicos , Saccharomycetales/crescimento & desenvolvimento , Saccharomycetales/metabolismo
2.
Food Microbiol ; 91: 103497, 2020 Oct.
Artigo em Inglês | MEDLINE | ID: mdl-32539965

RESUMO

In this work, Lactobacillus pentosus LPG1, Lactobacillus pentosus Lp13, Lactobacillus plantarum Lpl15, and Wickerhanomyces anomalous Y12, all of them previously isolated from fermented table olive biofilms, were used (alone or in combination) as multifunctional starters for Manzanilla Spanish-style green table olive fermentations. Their performances were evaluated through the changes in the key physico-chemical and microbiological parameters, correlation between AI-2 production and biofilm formation, inoculum imposition, metataxonomic analysis and sensory characteristics of the finished products. Inoculation only with lactic acid bacteria (LAB) strains led to higher titratable acidities and lower pH values than the spontaneous fermentation (non-inoculated control), mainly during the first steps of processing. However, the sequential inoculation of the yeast and then the combination of the 3 LAB strains showed the most favourable evolution. LPG1 strain and, particularly Lp13, were excellent biofilms former and showed the major imposition on the fruit epidermis, as corroborated by rep-PCR analysis. Production of AI-2 was lower in the treatment inoculated exclusively with yeast Y12 but had the highest presence in the sequential yeast-LAB inoculum, with its maximum concentration and maximum LAB population on fruits (19th days) strongly related. Metataxonomic analysis of the biofilms at the end of the fermentation revealed, in addition to Lactobacillus, high proportions of sequences from genera Marinilactobacillus, Alkalibacterium, Halolactobacillus, and low levels of Halomonas and Aerococcus. Compositional data analysis of the omics data revealed that Lpl15 was scarcely efficient for controlling the spontaneous microbiota since its treatment presented the highest proportions of Aerococcus genus. Finally, the sensory analysis showed similar characteristics for the treatment inoculated with LPG1 and the spontaneous process, with olives inoculated with the yeast (alone or in combination with Lactobacillus strains) showing attractive scores. Then, inoculation of Spanish-style table olive fermentations with a sequential yeast and LAB combination could be an advisable practice.


Assuntos
Alimentos e Bebidas Fermentados/microbiologia , Lactobacillus/metabolismo , Olea/microbiologia , Saccharomycetales/metabolismo , Bactérias/classificação , Bactérias/genética , Bactérias/isolamento & purificação , Bactérias/metabolismo , Biofilmes/crescimento & desenvolvimento , Técnicas de Cocultura , Fermentação , Alimentos e Bebidas Fermentados/análise , Microbiologia de Alimentos , Frutas/microbiologia , Homosserina/análogos & derivados , Homosserina/análise , Homosserina/biossíntese , Lactobacillus/classificação , Lactobacillus/crescimento & desenvolvimento , Lactonas/análise , Microbiota/genética , Saccharomycetales/crescimento & desenvolvimento
3.
J Nat Med ; 74(3): 545-549, 2020 Jun.
Artigo em Inglês | MEDLINE | ID: mdl-32236853

RESUMO

Fungal co-culture is a strategy to induce the production of secondary metabolites by activating cryptic genes. We discovered the production of a new compound, talarodone A (1), along with five known compounds 2-6 in co-culture of Talaromyces pinophilus and Paraphaeosphaeria sp. isolated from soil collected in Miyazaki Prefecture, Japan. Among them, the productions of penicidones C (2) and D (3) were enhanced 27- and sixfold, respectively, by the co-culture. The structure of 3 should be represented as a γ-pyridol form with the reported chemical shifts, but not as a γ-pyridone form, based on DFT calculation.


Assuntos
Piridonas/metabolismo , Saccharomycetales/metabolismo , Talaromyces/metabolismo , Técnicas de Cocultura , Japão , Piridonas/química , Saccharomycetales/crescimento & desenvolvimento , Saccharomycetales/isolamento & purificação , Microbiologia do Solo , Talaromyces/crescimento & desenvolvimento , Talaromyces/isolamento & purificação
4.
World J Microbiol Biotechnol ; 36(3): 43, 2020 Mar 04.
Artigo em Inglês | MEDLINE | ID: mdl-32130537

RESUMO

Second generation ethanol has the prospect of becoming an important bioenergy alternative. The development of this technology is associated with the lignocellulosic materials' use, with emphasis on agricultural and agroindustrial by-products from which fermentable sugar can be produced. The acid hydrolysis depolymerizes the hemicellulose releasing mainly xylose. Subsequently, the cellulose can be converted into glucose by enzymatic hydrolysis. However, the acid hydrolysis produces toxic compounds, such as furan derivatives, phenolics, and organic acids, which are harmful to fermentative microorganisms. This study investigated different acid concentrations in the sulfuric acid hydrolysis of sugarcane bagasse (1- 5% m/v) and the use of adsorbents with the prerogative to improve the acid hydrolysate (AH) quality for microbial ethanolic fermentation. Cell growth and fermentative yield of Saccharomyces cerevisiae (PE-2) and Scheffersomyces stipitis (NRRL Y-7124) were evaluated. AH was used as a source of pentoses (17.7 g L-1) and molasses (ME) sugarcane as source of hexoses (47 g L-1). The following adsorbents were used: activated charcoal, clay, hydrotalcite and active and inactive cells of PE-2 and NRRL Y-7124, at concentrations ranging (1 - 8% m/v). Results of cell growth and chemical characterization allowed to select the most effective adsorbents with emphasis for active cells that removed 66% furfural and 51% 5-(hydroxymethyl) furfural) (5-HMF) and alcoholic productivity of 23.5 g L-1 in AH and ME substrates, in the presence of mixed culture. These results indicate the application of active yeast cells in the detoxification of acid hydrolysates of the sugarcane bagasse previously to the fermentation.


Assuntos
Celulose/análise , Saccharomyces cerevisiae/crescimento & desenvolvimento , Saccharomycetales/crescimento & desenvolvimento , Saccharum/microbiologia , Adsorção , Hidróxido de Alumínio/química , Carvão Vegetal/química , Fermentação , Hexoses/química , Hidróxido de Magnésio/química , Pentoses/química , Saccharum/química
5.
Sci Rep ; 10(1): 4422, 2020 03 10.
Artigo em Inglês | MEDLINE | ID: mdl-32157123

RESUMO

In Tuber melanosporum cultivation, fruitbody traits are gaining relevance due to their increasing prominence on prices. We investigated the edaphic and temporal patterns of fruitbody traits and characterised the effect of truffle nests (localised peat-based amendment supplemented with T. melanosporum spores) on traits. We monitored fruitbody traits throughout two fruiting seasons in three blocks along a soil gradient. Each trait followed specific edaphic and temporal patterns. The number of fruitbodies per dig and spore maturity followed characteristic within-season trends, whereas fruitbody weight and infestation by truffle beetles were subject to complex interactions among edaphic and temporal variables, suggesting a relevant influence of annual environmental conditions. The application of truffle nests increased fruitbody depth, improved its shape and decreased infestation by truffle beetles. Nests increased the number of fruitbodies per dig, but only in two of the soils, suggesting a relevant role of the bulk soil/substrate interface in fruiting initiation. These results outline a complex scenario, with each trait being differently affected by environmental factors. In this scenario, nests proved to effectively modify several traits, although not always in the desired direction.


Assuntos
Carpóforos/crescimento & desenvolvimento , Saccharomycetales/crescimento & desenvolvimento , Agricultura , Fenótipo , Estações do Ano , Solo/química , Microbiologia do Solo
6.
Microb Cell Fact ; 19(1): 19, 2020 Feb 03.
Artigo em Inglês | MEDLINE | ID: mdl-32013957

RESUMO

BACKGROUND: A possible future shortage of feed protein will force mankind to explore alternative protein sources that can replace conventional soymeal or fishmeal. Several large industrial organic side-streams could potentially be upgraded to feed protein using a fermentation process to generate single cell protein. Yeast is the most widely accepted microorganism for production of single cell protein, because of its superior nutritional quality and acceptability among consumers. Here, we have assessed the growth of four different yeasts, Cyberlindnera jadinii, Wickerhamomyces anomalus, Blastobotrys adeninivorans and Thermosacc® Dry (Saccharomyces cerevisiae), on media composed of enzymatically saccharified sulfite-pulped spruce wood and hydrolysates of by-products from chicken, and we have characterized the resulting yeast biomass. RESULTS: Generally, the yeast grew very well on the spruce- and chicken-based medium, with typical yields amounting to 0.4-0.5 g of cell dry weight and 0.2-0.3 g of protein per g of sugar. B. adeninivorans stood out as the most versatile yeast in terms of nutrient consumption and in this case yields were as high as 0.9 g cells and 0.5 g protein per g of sugar. The next best performing yeast in terms of yield was W. anomalus with up to 0.6 g cells and 0.3 g protein per g sugar. Comparative compositional analyses of the yeasts revealed favorable amino acid profiles that were similar to the profiles of soymeal, and even more so, fish meal, especially for essential amino acids. CONCLUSIONS: The efficient conversion of industrial biomass streams to yeast biomass demonstrated in this study opens new avenues towards better valorization of these streams and development of sustainable feed ingredients. Furthermore, we conclude that production of W. anomalus or B. adeninivorans on this promising renewable medium may be potentially more efficient than production of the well-known feed ingredient C. jadinii. Further research should focus on medium optimization, development of semi-continuous and continues fermentation protocols and exploration of downstream processing methods that are beneficial for the nutritional values of the yeast for animal feed.


Assuntos
Meios de Cultura/química , Fermentação , Saccharomycetales , Animais , Carboidratos/química , Galinhas/metabolismo , Picea/metabolismo , Hidrolisados de Proteína/química , Saccharomycetales/crescimento & desenvolvimento , Saccharomycetales/metabolismo
7.
Int J Food Microbiol ; 318: 108471, 2020 Apr 02.
Artigo em Inglês | MEDLINE | ID: mdl-31841786

RESUMO

This work presents the attempt to enhance the flavor complexity of cider fermented by different non-Saccharomyces species. Pichia kluyveri and Hanseniaspora vineae pure cultures were used as reference ciders. Mixed cultures between all 4 species gave 5 fermentations, where Hanseniaspora uvarum or Torulaspora quercuum were included for apple juice fermentation. Chemical composition and sensorial properties of all ciders were studied. The results indicated that the growth of P. kluyveri and H. vineae were interreacted and also affected by H. uvarum and T. quercuum. H. vineae was more capable of consuming sugar than P. kluyveri. Ciders from the single culture fermentation with P. kluyveri (Pk), as well as from mixed fermentation with P. kluyveri and H. uvarum (Pk-Hu), had high residual sugar, sugar/acid ratio, and glucose-fructose consumption ratio. Large shifts in the consumption and production of organic acids and polyphenols among all ciders were observed. The calculation of the relative odor activity value (rOAV) showed that 17 volatile compounds had an rOAV >1 in at least one sample, and acetate esters and ethyl esters were the groups with the highest number of volatile compounds of importance to the cider aroma. Among these 17 compounds, 3-methylbutyl acetate, 2-methylbutyl acetate, ethyl hexanoate, ethyl octanoate, and ß-damascenone exhibited high rOAVs in some ciders and might contribute fruity, floral, and sweet features to the cider aroma. Besides, the tropical fruity aroma from 3-methylbutyl acetate was only perceived in Pk and Pk-Hu. The partial least squares regression (PLSR) analysis revealed that acetate esters contributed positively to the roasted and cooked odor of all ciders. This is the first study evaluating simultaneous fermentation of two non-Saccharomyces yeasts to produce cider, which provides new insights into cider production.


Assuntos
Bebidas Alcoólicas/análise , Bebidas Alcoólicas/microbiologia , Saccharomycetales/metabolismo , Reatores Biológicos/microbiologia , Fermentação , Aromatizantes/análise , Sucos de Frutas e Vegetais/análise , Sucos de Frutas e Vegetais/microbiologia , Malus , Odorantes/análise , Saccharomycetales/classificação , Saccharomycetales/crescimento & desenvolvimento , Especificidade da Espécie , Paladar
8.
J Appl Microbiol ; 128(3): 853-861, 2020 Mar.
Artigo em Inglês | MEDLINE | ID: mdl-31733170

RESUMO

AIM: The aim of the present study was to investigate the in vitro antioxidant activity of yeast strains isolated from virgin olive oil. METHODS AND RESULTS: The 2,2-diphenyl-1-picryl-hydrazyl (DPPH) free-radical scavenging activity of single cultures of 24 yeast strains belonging to eight species isolated from virgin olive oil was evaluated and compared with that of the reference yeast Saccharomyces boulardii. All the yeasts studied in vitro showed antioxidant activity similar to or superior to that of the reference yeast. The highest antioxidant activity was observed in Nakazawaea wickerhamii, which exceeded the value reached by the reference strain S. boulardii, while the significantly lowest values were observed in the Candida adriatica, Candida diddensiae and Barnettozyma californica strains. Tests performed with virgin olive oil enriched with Wickerhamomyces anomalus and S. boulardii yeast biomasses showed a positive correlation between the microbial biomass used and the percentage of antioxidant activity observed during 60 days of storage. Survival in virgin olive oil was also significantly higher for W. anomalus compared to S. boulardii. CONCLUSIONS: All the oil-borne yeasts studied showed DPPH free-radical scavenging activity in both aqueous and oily media. SIGNIFICANCE AND IMPACT OF THE STUDY: For the first time, the antioxidant activity of the microbiota of virgin olive oil is reported. This activity may indicate the probiotic characteristics of the microbiota.


Assuntos
Antioxidantes/metabolismo , Azeite de Oliva , Saccharomycetales/isolamento & purificação , Saccharomycetales/metabolismo , Biomassa , Compostos de Bifenilo/metabolismo , Microbiologia de Alimentos , Microbiota , Picratos/metabolismo , Probióticos , Saccharomycetales/classificação , Saccharomycetales/crescimento & desenvolvimento
9.
Molecules ; 24(21)2019 Oct 31.
Artigo em Inglês | MEDLINE | ID: mdl-31683743

RESUMO

Onychomycosis is a major health problem due to its chronicity and resistance to therapy. Because some cases associate paronychia, any therapy must target the fungus and the inflammation. Medicinal plants represent an alternative for onychomycosis control. In the present work the antifungal and antioxidant activities of Alium sativum extract against Meyerozyma guilliermondii (Wick.) Kurtzman & M. Suzuki and Rhodotorula mucilaginosa (A. Jörg.) F.C. Harrison, isolated for the first time from a toenail onychomycosis case, were investigated. The fungal species were confirmed by DNA molecular analysis. A. sativum minimum inhibitory concentration (MIC) and ultrastructural effects were examined. At the MIC concentration (120 mg/mL) the micrographs indicated severe structural alterations with cell death. The antioxidant properties of the A. sativum extract were evaluated is a rat turpentine oil induced inflammation, and compared to an anti-inflammatory drug, diclofenac, and the main compound from the extract, allicin. A. sativum reduced serum total oxidative status, malondialdehyde and nitric oxide production, and increased total thiols. The effects were comparable to those of allicin and diclofenac. In conclusion, the garlic extract had antifungal effects against M. guilliermondii and R. mucilaginosa, and antioxidant effect in turpentine-induced inflammation. Together, the antifungal and antioxidant activities support that A. sativum is a potential alternative treatment in onychomycosis.


Assuntos
Antifúngicos/uso terapêutico , Antioxidantes/uso terapêutico , Alho/química , Onicomicose/tratamento farmacológico , Onicomicose/microbiologia , Extratos Vegetais/uso terapêutico , Rhodotorula/química , Saccharomycetales/química , Animais , Antifúngicos/farmacologia , Antioxidantes/farmacologia , Benzotiazóis/química , Compostos de Bifenilo/química , Contagem de Colônia Microbiana , Depuradores de Radicais Livres/química , Humanos , Masculino , Unhas/efeitos dos fármacos , Unhas/microbiologia , Unhas/patologia , Compostos Fitoquímicos/análise , Compostos Fitoquímicos/farmacologia , Picratos/química , Extratos Vegetais/farmacologia , Ratos Wistar , Rhodotorula/efeitos dos fármacos , Rhodotorula/crescimento & desenvolvimento , Rhodotorula/ultraestrutura , Saccharomycetales/efeitos dos fármacos , Saccharomycetales/crescimento & desenvolvimento , Saccharomycetales/ultraestrutura , Ácidos Sulfônicos/química
10.
J Biotechnol ; 304: 28-30, 2019 Oct 10.
Artigo em Inglês | MEDLINE | ID: mdl-31415788

RESUMO

The possibility of using active dry microbial preparations in biotechnological processes is essential for the development of new modern industrial technologies. In this study, we show the possibility of obtaining such preparations of the genetically engineered yeast strain Ogataea (Hansenula) polymorpha with glutathione overproduction. Special pre-treatment involving the gradual rehydration of dry cells in water vapour led to the restoration/reactivation of almost 100% of dehydrated cells. Furthermore, dry cells do not lose their viability during storage at room temperatures. Application of dry cells as the inoculum provides the same levels of glutathione synthesis as that of a native yeast culture.


Assuntos
Glutationa Sintase/genética , Glutationa/biossíntese , Saccharomycetales/crescimento & desenvolvimento , Fatores de Transcrição de Zíper de Leucina Básica/genética , Dessecação , Hidratação , Engenharia Genética , Glutationa Sintase/metabolismo , Viabilidade Microbiana , Saccharomycetales/genética , Saccharomycetales/metabolismo
11.
J Basic Microbiol ; 59(8): 792-806, 2019 Aug.
Artigo em Inglês | MEDLINE | ID: mdl-31368594

RESUMO

The aim of this study was to examine four strains of two yeast species in relation to their capability for assimilating alkanes in the presence of heavy metals (HMs). The four strains tested were Candida pseudoglaebosa ENCB-7 and Kodamaea ohmeri ENCB-8R, ENCB-23, and ENCB-VIK. Determination was made of the expression of CYP52 genes involved in alkane hydroxylation. When exposed to Cu2+ , Zn2+ , Pb2+ , Cd2+ , and As3+ at pH 3 and 5, all four strains could assimilate several n-alkanes having at least six carbon atoms. The three K. ohmeri strains could also utilize branched alkanes, cycloalkanes, and n-octanol as sole carbon sources. Kinetic assays demonstrated greater biomass production and specific growth of the yeasts exposed to long-chain n-alkanes. Fragments of paralogous CYP52 genes of C. pseudoglaebosa ENCB-7 and K. ohmeri ENCB-23 were amplified, sequenced, and phylogenetically evaluated. Reverse-transcription polymerase chain reaction revealed that n-nonane and n-decane induced to CpCYP52-G3, CpCYP52-G9, and CpCYP52-G10. KoCYP52-G3 was induced with n-decane and n-octanol. Also, CpCYP52-G3 and CpCYP52-G9 were induced by glucose. In conclusion, C. pseudoglaebosa and K. ohmeri were able to degrade several alkanes in the presence of HMs and under acidic conditions. These yeasts harbor paralogous alkane-induced CYP52 genes, which display different profiles of transcriptional expression.


Assuntos
Alcanos/metabolismo , Metais Pesados/metabolismo , Saccharomycetales/metabolismo , Alcanos/química , Biodegradação Ambiental , Biomassa , Candida/classificação , Candida/genética , Candida/crescimento & desenvolvimento , Candida/metabolismo , Sistema Enzimático do Citocromo P-450/genética , DNA Ribossômico/genética , Proteínas Fúngicas/genética , Concentração de Íons de Hidrogênio , Cinética , Filogenia , Saccharomycetales/classificação , Saccharomycetales/genética , Saccharomycetales/crescimento & desenvolvimento
12.
Environ Monit Assess ; 191(9): 531, 2019 Aug 02.
Artigo em Inglês | MEDLINE | ID: mdl-31375926

RESUMO

Microbially produced biosurfactants are fast catching up due to their environment-friendly approach over chemical surfactants. But their commercial production is restricted due to poor economy of the production process which could be improved by using high yielding microbial strains and optimizing the process parameters. The present research was directed to optimize the biosurfactant production monitored in terms of oil displacement and emulsification (E24) index, using a promising yeast Meyerozyma guilliermondii YK32. Maximum oil displacement equaling 7.5 cm was obtained with olive oil at 8% (v/v) concentration as carbon source under shaking conditions (150 rpm). Diesel being a complex hydrocarbon was not utilized easily by yeast and showed poor biosurfactant production. Yeast extract at 1.5% (w/v) concentration yielded maximum biosurfactant as evident from maximum oil displacement and E24 index equal to 8.1 cm and 52.6%, respectively. Sodium chloride at the rate of 3% (w/v) supported maximum oil displacement (8.8 cm) using the production broth containing optimized carbon and nitrogen sources. Any increase beyond this level negatively influenced the biosurfactant production. The yield was at its maximum at 30 °C as a shift in temperature either to 35 °C or 25 °C decreased the oil displacement from 8.8 to 5.2 or 7.6 cm, respectively. At 40 °C, oil displacement was decreased to 2.5 cm. Biosurfactant production appeared to be sensitive to varying pH as evident from the E24 index as high as 67.3% at pH 6.0 as compared with 60.2%, 60.1%, and 52.4% at pH 5.0, 5.5, and 7.0, respectively. Yeast biomass yield equivalent to 10.3 g/L and 8.3 g/L was recorded at pH 6 and 7, respectively, during the production process. Elimination of shaking reduced the E24 index from 67.3 to 34.8% under optimized conditions.


Assuntos
Monitoramento Ambiental/métodos , Saccharomycetales/metabolismo , Tensoativos/metabolismo , Biomassa , Carbono/metabolismo , Hidrocarbonetos/metabolismo , Nitrogênio/metabolismo , Saccharomycetales/crescimento & desenvolvimento , Temperatura
13.
Elife ; 82019 08 09.
Artigo em Inglês | MEDLINE | ID: mdl-31397671

RESUMO

Production of healthy gametes in meiosis relies on the quality control and proper distribution of both nuclear and cytoplasmic contents. Meiotic differentiation naturally eliminates age-induced cellular damage by an unknown mechanism. Using time-lapse fluorescence microscopy in budding yeast, we found that nuclear senescence factors - including protein aggregates, extrachromosomal ribosomal DNA circles, and abnormal nucleolar material - are sequestered away from chromosomes during meiosis II and subsequently eliminated. A similar sequestration and elimination process occurs for the core subunits of the nuclear pore complex in both young and aged cells. Nuclear envelope remodeling drives the formation of a membranous compartment containing the sequestered material. Importantly, de novo generation of plasma membrane is required for the sequestration event, preventing the inheritance of long-lived nucleoporins and senescence factors into the newly formed gametes. Our study uncovers a new mechanism of nuclear quality control and provides insight into its function in meiotic cellular rejuvenation.


Assuntos
Fatores Biológicos/metabolismo , Substâncias Macromoleculares/metabolismo , Meiose , Saccharomycetales/crescimento & desenvolvimento , Saccharomycetales/metabolismo , Microscopia de Fluorescência , Saccharomycetales/citologia , Imagem com Lapso de Tempo
14.
J Biotechnol ; 303: 30-36, 2019 Sep 10.
Artigo em Inglês | MEDLINE | ID: mdl-31348962

RESUMO

Komagataella pastoris was recently proposed as a source of valuable polysaccharides, namely, the co-polymer chitin-glucan complex (CGC) and mannose-containing polymers (mannans), that are extracted from its cell-wall. In this study, a novel cultivation medium, Medium K, was developed envisaging the simultaneous production of both types of cell-wall polysaccharides. The use of Medium K for the cultivation of K. pastoris resulted in high contents of CGC (19 wt%) and mannans (21 wt%) in the biomass, corresponding to significantly higher products' volumetric productivities (17.5 and 19.2 g/L day, respectively) compared to previous studies. The produced CGC had a chitin:ß-glucan molar ratio of 12:88, similarly to previously reported values for K. pastoris CGC (11:89-19:81), while the mannans were mainly composed of mannose units, with a protein content of 10 wt%. These results demonstrated that the developed optimized medium was suitable for cultivation of K. pastoris and the production of both CGC and mannans. It comprised fewer components with considerably reduced salts content, thus representing a significant simplification of the bioprocess with no precipitation problems, without impacting on the polymers' composition.


Assuntos
Meios de Cultura/química , Polissacarídeos Fúngicos/metabolismo , Mananas/metabolismo , Saccharomycetales/crescimento & desenvolvimento , Técnicas de Cultura Celular por Lotes , Reatores Biológicos/microbiologia , Parede Celular/metabolismo , Quitina/metabolismo , Contagem de Colônia Microbiana , Glucanos/metabolismo , Saccharomycetales/metabolismo
15.
Proc Natl Acad Sci U S A ; 116(33): 16454-16462, 2019 08 13.
Artigo em Inglês | MEDLINE | ID: mdl-31266891

RESUMO

The programmed release of apoptogenic proteins from mitochondria is a core event of apoptosis, although ancestral roles of this phenomenon are not known. In mammals, one such apoptogenic protein is Endonuclease G (EndoG), a conserved mitochondrial nuclease that fragments the DNA of dying cells. In this work, we show that budding yeast executes meiotically programmed mitochondrial release of an EndoG homolog, Nuc1, during sporulation. In contrast to EndoG's ostensible pro-death function during apoptosis, Nuc1 mitochondrial release is pro-survival, attenuating the cytosolic L-A and Killer double-stranded RNA mycoviruses and protecting meiotic progeny from the catastrophic consequences of their derepression. The protective viral attenuation role of this pathway illuminates a primordial role for mitochondrial release of EndoG, and perhaps of apoptosis itself.


Assuntos
Apoptose/genética , Endonucleases/genética , Exonucleases/genética , Meiose/genética , Proteínas de Saccharomyces cerevisiae/genética , Saccharomycetales/genética , Animais , Endodesoxirribonucleases/genética , Mamíferos , Mitocôndrias/enzimologia , Mitocôndrias/genética , Saccharomycetales/crescimento & desenvolvimento , Saccharomycetales/virologia , Esporos Fúngicos/genética , Esporos Fúngicos/crescimento & desenvolvimento
16.
Meat Sci ; 157: 107875, 2019 Nov.
Artigo em Inglês | MEDLINE | ID: mdl-31254801

RESUMO

Debaryomyces hansenii Lr1, previously isolated from naturally fermented cured pork loin ("lomo embuchado"), was used to inoculate Iberian pork loin under four different conditions. In all cases, specifically inoculated D. hansenii yeasts grew on the surface of the product and affected its physico-chemical and sensory characteristics. Inoculated pork loin kept higher water activity and pH and possessed lower sodium content than control samples at the end of the 90 days ripening period. Moreover, inoculation with Lr1 yeast did not change the general profile of fatty acids but modified the levels of volatile and aroma compounds by decreasing aldehydes and increasing esters and alcohol compounds. Principal Component Analysis (PCA) of the different physico-chemical parameters that were determined showed a clear separation between the samples indicating that they were different. A tendency in consumers acceptance to prefer cured pork loin specifically inoculated with the higher amounts of yeasts used in this study was observed.


Assuntos
Manipulação de Alimentos/métodos , Produtos da Carne/análise , Saccharomycetales/crescimento & desenvolvimento , Adulto , Animais , Feminino , Fermentação , Microbiologia de Alimentos , Humanos , Masculino , Produtos da Carne/microbiologia , Pessoa de Meia-Idade , Olfato , Espanha , Suínos , Paladar , Compostos Orgânicos Voláteis/análise
17.
Phys Rev Lett ; 122(20): 208102, 2019 May 24.
Artigo em Inglês | MEDLINE | ID: mdl-31172757

RESUMO

Growth in confined spaces can drive cellular populations through a jamming transition from a fluidlike state to a solidlike state. Experiments have found that jammed budding yeast populations can build up extreme compressive pressures (over 1 MPa), which in turn feed back onto cellular physiology by slowing or even stalling cell growth. Using numerical simulations, we investigate how this feedback impacts the mechanical properties of model jammed cell populations. We find that feedback directs growth toward poorly coordinated regions, resulting in an excess number of cell-cell contacts that rigidify cell packings. Cell packings possess anomalously large shear and bulk moduli that depend sensitively on the strength of feedback. These results demonstrate that mechanical feedback on the single-cell level is a simple mechanism by which living systems may tune their population-level mechanical properties.


Assuntos
Modelos Biológicos , Saccharomycetales/fisiologia , Fenômenos Biomecânicos , Retroalimentação Fisiológica , Saccharomycetales/crescimento & desenvolvimento , Saccharomycetales/metabolismo
18.
Food Chem ; 294: 293-301, 2019 Oct 01.
Artigo em Inglês | MEDLINE | ID: mdl-31126466

RESUMO

To construct a high-performance engineered endo-inulinase for fructo-oligosaccharides (FOS) production from inulin, an inulin binding module (IBM) was fused into either N- or C-terminal of an endo-inulinase. After heterologous expression, purification and characterization, the C-terminal fusion one (Eninu-IBM) with better activity, thermostability and inulin binding ability was employed for high-temperature in situ inulin hydrolysis in a 10-L fermentor. During this process, Eninu-IBM was first efficiently produced by the yeast cells at 28 °C for 96 h, and subsequently 1600 g unsterilized inulin per liter fermentation liquor was directly supplemented into the bioreactor for FOS production at 60 °C for 2 h. Finally, high purity of FOS (91.4%) were obtained with FOS titer, yield and productivity of 717.3 g/L, 0.912 gFOS/gInulin and 358.6 g/L/h, respectively. The in vitro prebiotic assay indicated that the final FOS products with main polymerization degrees of 3-5 were preferably fermented by beneficial bifidobacteria and lactobacilli.


Assuntos
Glicosídeo Hidrolases/metabolismo , Inulina/metabolismo , Oligossacarídeos/metabolismo , Reatores Biológicos , Glicosídeo Hidrolases/genética , Concentração de Íons de Hidrogênio , Hidrólise , Cinética , Prebióticos , Estabilidade Proteica , Proteínas Recombinantes/biossíntese , Proteínas Recombinantes/isolamento & purificação , Saccharomycetales/crescimento & desenvolvimento , Saccharomycetales/metabolismo , Temperatura
19.
Appl Microbiol Biotechnol ; 103(11): 4347-4362, 2019 Jun.
Artigo em Inglês | MEDLINE | ID: mdl-30949810

RESUMO

Both strain engineering and process optimization are intensively studied in microbial biosurfactant literature. However, screening of multiple strains and/or medium components in parallel is a very labor-intensive and timely process, considering the only applied technique nowadays is evaluation through shake flask and/or bioreactor experiments. Therefore, in this work, the development, optimization, and application of a more throughput technique-based on 24-deep well plates-are described for a new Starmerella bombicola strain producing bolaform sophorolipids. To develop an optimal setup, the influence of plate position and culture volume and the type of sandwich cover was investigated. Optimal parameters, which did not result in significant differences compared with shake flask experiments concerning growth, glucose consumption, and production of novel sophorolipids, were defined and validated. Next, the new method was applied to evaluate the influence of the use of alternative (commercial) nitrogen sources in comparison with the yeast extract currently applied in the production medium, aiming to increase production efficiency. Self-made yeast extracts from S. bombicola cells were also included to evaluate possible recycling of cells after fermentation. In conclusion, the designed method enabled the efficient and successful comparison of ten different nitrogen sources in varying concentrations (1, 4, and 10 g/L) on bola sophorolipid production, which can now also be performed for other parameters important for growth and/or glycolipid production.


Assuntos
Engenharia Metabólica/métodos , Técnicas Microbiológicas/métodos , Ácidos Oleicos/biossíntese , Saccharomycetales/metabolismo , Meios de Cultura/química , Fermentação , Miniaturização , Saccharomycetales/crescimento & desenvolvimento
20.
Biotechnol Lett ; 41(6-7): 753-761, 2019 Jul.
Artigo em Inglês | MEDLINE | ID: mdl-30963342

RESUMO

OBJECTIVE: A correlation among different volumetric oxygen transfer coefficients (kLa) and the oxireduction potential (ORP) in batch fermentations using Scheffersomyces stipitis was evaluated. Experiments were performed using a mixture of xylose and glucose as the substrates. RESULTS: Microaerophilic condition (kLa = 4.9 h-1) have shown to be suitable when compared to complete anaerobiosis (kLa = 0), providing an ethanol yield and a productivity after 48 h of 64.3% and 0.45 g ethanol L-1 h-1, respectively; the maximum ethanol titer obtained was 21.50 g ethanol L-1. Values of ORP varying from - 270 to - 330 mV resulted in high ethanol production from xylose by S. stipitis. CONCLUSIONS: Different ORP values were found in anaerobiosis and kLa 4.9 h-1, suggesting that for ethanol production by S. stipitis, values from - 270 to - 330 mV are favorable under the studied circumstances. In this ORP range, the greatest rates of xylose consumption and ethanol production were registered. ORP monitoring was demonstrated to be a suitable option for online control throughout the fermentation processes, which may provide a more efficient bioprocess operation with a very low O2 concentration.


Assuntos
Meios de Cultura/química , Etanol/metabolismo , Fermentação , Glucose/metabolismo , Oxirredução , Saccharomycetales/metabolismo , Xilose/metabolismo , Aerobiose , Anaerobiose , Biotransformação , Saccharomycetales/crescimento & desenvolvimento
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