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1.
Chinese Journal of Biotechnology ; (12): 429-447, 2021.
Article in Chinese | WPRIM | ID: wpr-878573

ABSTRACT

Higher alcohols are one of the main by-products of Saccharomyces cerevisiae in brewing. High concentration of higher alcohols in alcoholic beverages easily causes headache, thirst and other symptoms after drinking. It is also the main reason for chronic drunkenness and difficulty in sobering up after intoxication. The main objective of this review is to present an overview of the flavor characteristics and metabolic pathways of higher alcohols as well as the application of mutagenesis breeding techniques in the regulation of higher alcohol metabolism in S. cerevisiae. In particular, we review the application of metabolic engineering technology in genetic modification of amino transferase, α-keto acid metabolism, acetate metabolism and carbon-nitrogen metabolism. Moreover, key challenges and future perspectives of realizing optimization of higher alcohols metabolism are discussed. This review is intended to provide a comprehensive understanding of metabolic regulation system of higher alcohols in S. cerevisiae and to provide insights into the rational development of the excellent industrial S. cerevisiae strains producing higher alcohols.


Subject(s)
Alcoholic Beverages , Alcohols/analysis , Fermentation , Saccharomyces cerevisiae/metabolism , Saccharomyces cerevisiae Proteins/metabolism
2.
Electron. j. biotechnol ; 46: 55-64, jul. 2020. tab, graf
Article in English | LILACS | ID: biblio-1223246

ABSTRACT

BACKGROUND: Ethanol concentration (PE), ethanol productivity (QP) and sugar consumption (SC) are important values in industrial ethanol production. In this study, initial sugar and nitrogen (urea) concentrations in sweet sorghum stem juice (SSJ) were optimized for high PE (≥10%, v/v), QP, (≥2.5 g/L·h) and SC (≥90%) by Saccharomyces cerevisiae SSJKKU01. Then, repeated-batch fermentations under normal gravity (NG) and high gravity (HG) conditions were studied. RESULTS: The initial sugar at 208 g/L and urea at 2.75 g/L were the optimum values to meet the criteria. At the initial yeast cell concentration of ~1 × 108 cells/mL, the PE, QP and SC were 97.06 g/L, 3.24 g/L·h and 95.43%, respectively. Repeated-batch fermentations showed that the ethanol production efficiency of eight successive cycles with and without aeration were not significantly different when the initial sugar of cycles 2 to 8 was under NG conditions (~140 g/L). Positive effects of aeration were observed when the initial sugar from cycle 2 was under HG conditions (180­200 g/L). The PE and QP under no aeration were consecutively lower from cycle 1 to cycle 6. Additionally, aeration affected ergosterol formation in yeast cell membrane at high ethanol concentrations, whereas trehalose content under all conditions was not different. CONCLUSION: Initial sugar, sufficient nitrogen and appropriated aeration are necessary for promoting yeast growth and ethanol fermentation. The SSJ was successfully used as an ethanol production medium for a high level of ethanol production. Aeration was not essential for repeated-batch fermentation under NG conditions, but it was beneficial under HG conditions.


Subject(s)
Saccharomyces cerevisiae/metabolism , Sorghum/chemistry , Ethanol/metabolism , Saccharomyces cerevisiae/growth & development , Urea , Yeasts/growth & development , Aeration , Sorghum/microbiology , Ethanol/analysis , Sugars , Juices , Fermentation , Gravitation , Nitrogen
3.
Biol. Res ; 53: 02, 2020. tab, graf
Article in English | LILACS | ID: biblio-1089077

ABSTRACT

The budding yeast Saccharomyces cerevisiae has been considered for more than 20 years as a premier model organ- ism for biological sciences, also being the main microorganism used in wide industrial applications, like alcoholic fermentation in the winemaking process. Grape juice is a challenging environment for S. cerevisiae , with nitrogen deficiencies impairing fermentation rate and yeast biomass production, causing stuck or sluggish fermentations, thus generating sizeable economic losses for wine industry. In the present review, we summarize some recent efforts in the search of causative genes that account for yeast adaptation to low nitrogen environments, specially focused in wine fermentation conditions. We start presenting a brief perspective of yeast nitrogen utilization under wine fermentative conditions, highlighting yeast preference for some nitrogen sources above others. Then, we give an outlook of S. cerevisiae genetic diversity studies, paying special attention to efforts in genome sequencing for population structure determination and presenting QTL mapping as a powerful tool for phenotype-genotype correlations. Finally, we do a recapitulation of S. cerevisiae natural diversity related to low nitrogen adaptation, specially showing how different studies have left in evidence the central role of the TORC1 signalling pathway in nitrogen utilization and positioned wild S. cerevisiae strains as a reservoir of beneficial alleles with potential industrial applications (e.g. improvement of industrial yeasts for wine production). More studies focused in disentangling the genetic bases of S. cerevisiae adaptation in wine fermentation will be key to determine the domestication effects over low nitrogen adaptation, as well as to definitely proof that wild S. cerevisiae strains have potential genetic determinants for better adaptation to low nitrogen conditions.


Subject(s)
Saccharomyces cerevisiae/metabolism , Wine/microbiology , Adaptation, Physiological , Vitis/metabolism , Fermentation , Nitrogen/metabolism , Saccharomyces cerevisiae/growth & development , Vitis/microbiology
4.
Electron. j. biotechnol ; 37: 56-60, Jan. 2019. tab
Article in English | LILACS | ID: biblio-1051261

ABSTRACT

Heavy metals are natural elements in the Earth's crust that can enter human food through industrial or agricultural processing, in the form of fertilizers and pesticides. These elements are not biodegradable. Some heavy metals are known as pollutants and are toxic, and their bioaccumulation in plant and animal tissues can cause undesirable effects for humans; therefore, their amount in water and food should always be under control. The aim of this study is to investigate the conditions for the bioremediation of heavy metals in foods. Various physical, chemical, and biological methods have been used to reduce the heavy metal content in the environment. During the last decades, bioremediation methods using plants and microorganisms have created interest to researchers for their advantages such as being more specific and environmentally friendly. The main pollutant elements in foods and beverages are lead, cadmium, arsenic, and mercury, which have their own permissible limits. Among the microorganisms that are capable of bioremediation of heavy metals, Saccharomyces cerevisiae is an interesting choice for its special characteristics and being safe for humans, which make it quite common and useful in the food industry. Its mass production as the byproduct of the fermentation industry and the low cost of culture media are the other advantages. The ability of this yeast to remove an individual separated element has also been widely investigated. In countries with high heavy metal pollution in wheat, the use of S. cerevisiae is a native solution for overcoming the problem of solution. This article summarizes the main conditions for heavy metal absorption by S. cerevisiae.


Subject(s)
Saccharomyces cerevisiae/metabolism , Biodegradation, Environmental , Food Industry , Metals, Heavy/metabolism , Arsenic , Yeasts , Cadmium , Contaminant Removal , Absorption , Bioaccumulation , Lead , Mercury
5.
Electron. j. biotechnol ; 42: 1-5, Nov. 2019. tab, graf
Article in English | LILACS | ID: biblio-1087340

ABSTRACT

Background: Fermentation strategies for bioethanol production that use flocculating Saccharomyces cerevisiae yeast need to account for the mechanism by which inhibitory compounds, generated in the hydrolysis of lignocellulosic materials, are tolerated and detoxified by a yeast floc. Results: Diffusion coefficients and first-order kinetic bioconversion rate coefficients were measured for three fermentation inhibitory compounds (furfural, hydroxymethylfurfural, and vanillin) in self-aggregated flocs of S. cerevisiae NRRL Y-265. Thièle-type moduli and internal effectiveness factors were obtained by simulating a simple steady-state spherical floc model. Conclusions: The obtained values for the Thiéle moduli and internal effectiveness factors showed that the bioconversion rate of the inhibitory compounds is the dominant phenomenon over mass transfer inside the flocs.


Subject(s)
Saccharomyces cerevisiae/metabolism , Biofuels , Yeasts , Benzaldehydes , Biodegradation, Environmental , Inactivation, Metabolic , Diffusion , Flocculation , Furaldehyde/analogs & derivatives
6.
Braz. j. microbiol ; 49(4): 808-815, Oct.-Dec. 2018. tab, graf
Article in English | LILACS | ID: biblio-974288

ABSTRACT

ABSTRACT Chicha, a type of beer made mainly with maize or cassava, is a traditional fermented beverage of the Andean region. There have only been a few studies on yeasts associated with chicha fermentation, and the species diversity occurring during the production of this beverage is not known. The objective of this study was to determine the biodiversity of yeasts in chicha, and to characterize the Saccharomyces cerevisiae populations associated with the production of chicha de jora, seven-grain chicha, chicha de yuca, and chicha de morocho in Ecuador. The molecular diversity of S. cerevisiae populations was determined by restriction polymorphism mitochondrial profiles. The beverages were characterized based on their physicochemical parameters. Twenty-six species were identified, and the most prevalent species were S. cerevisiae and Torulaspora delbrueckii. Other yeast species were isolated at low frequencies. Among 121 isolates of S. cerevisiae, 68 different mtDNA molecular profiles were identified. These results showed that chichas are fermented by a high number of different strains of S. cerevisiae. Some other species provided a minor contribution to the fermentation process. The chicha presented generally similar physicochemical parameters to those observed for other traditional fermented beverages, and can be considered as an acid fermented beverage.


Subject(s)
Saccharomyces cerevisiae/isolation & purification , Beer/microbiology , Yeasts/isolation & purification , Yeasts/metabolism , Saccharomyces cerevisiae/classification , Saccharomyces cerevisiae/genetics , Saccharomyces cerevisiae/metabolism , Beer/analysis , Yeasts/classification , Yeasts/genetics , Manihot/metabolism , Manihot/microbiology , Zea mays/metabolism , Zea mays/microbiology , Biodiversity , Ecuador , Fermentation
7.
Electron. j. biotechnol ; 34: 1-8, july. 2018. tab, graf
Article in English | LILACS | ID: biblio-1026812

ABSTRACT

Background: Ethanol and fructose are two important industrial products that enjoy many uses. In this contribution, their production via selective fermentation of date extract using Saccharomyces cerevisiae was studied. Scaling up the process for possible commercialization was investigated in three fermentors with working volume ratio of 1:40:400. Results: Higher ethanol concentration was obtained in the larger fermentor due to conversion of fructose. Fructose yields in the 0.5-L, 7.5-L and 80-L fermentors were 99, 92 and 90%, respectively. Good fitting was obtained with the modified Monod kinetics; however, a better fit of cell mass was obtained with the modified Ghose­Tyagi model which accounts for ethanol inhibition. Conclusions: The modified Gompertz model was expanded to facilitate prediction of products' formation and fructose fractions in all three fermentors. Such expansion will be beneficial in industrial applications.


Subject(s)
Saccharomyces cerevisiae/metabolism , Ethanol/chemical synthesis , Fructose/biosynthesis , Yeasts , Kinetics , Bioreactors , Fermentation
8.
Braz. j. microbiol ; 49(supl.1): 140-150, 2018. tab, graf
Article in English | LILACS | ID: biblio-974343

ABSTRACT

Abstract Ethanol production from sweet sorghum juice (SSJ) using the thermotolerant Saccharomyces cerevisiae strain DBKKUY-53 immobilized in an alginate-loofah matrix (ALM) was successfully developed. As found in this study, an ALM with dimensions of 20 × 20 × 5 mm3 is effective for cell immobilization due to its compact structure and long-term stability. The ALM-immobilized cell system exhibited greater ethanol production efficiency than the freely suspended cell system. By using a central composite design (CCD), the optimum conditions for ethanol production from SSJ by ALM-immobilized cells were determined. The maximum ethanol concentration and volumetric ethanol productivity obtained using ALM-immobilized cells under the optimal conditions were 97.54 g/L and 1.36 g/L h, respectively. The use of the ALM-immobilized cells was successful for at least six consecutive batches (360 h) without any loss of ethanol production efficiency, suggesting their potential application in industrial ethanol production.


Subject(s)
Saccharomyces cerevisiae/metabolism , Industrial Microbiology/methods , Sorghum/microbiology , Ethanol/metabolism , Saccharomyces cerevisiae/chemistry , Cells, Immobilized/metabolism , Cells, Immobilized/chemistry , Sorghum/metabolism , Sorghum/chemistry , Ethanol/analysis , Alginates/chemistry , Fermentation
9.
Pesqui. vet. bras ; 38(3): 382-386, mar. 2018. ilus
Article in Portuguese | ID: biblio-964214

ABSTRACT

O presente trabalho descreve um surto de intoxicação por etanol que afetou um rebanho bovino de aptidão leiteira alimentado com o subproduto de cervejaria denominado bagaço de malte, resíduo úmido de cervejaria (RUC), resíduo de cevada maltada ou simplesmente "cevada". O surto iniciou cerca de 24 horas após ao fornecimento de uma nova partida do subproduto que apresentava odor alcoólico. Análise cromatográfica e microbiológica de amostra deste subproduto confirmou a presença de etanol e Saccharomyces spp., respectivamente, indicando a adição de outro subproduto de cervejaria, a levedura de cerveja ou levedo. Os principais sinais clínicos observados foram diarreia, salivação, andar cambaleante e decúbito. A morbidade foi de 12,2% (5/41) e mortalidade de 2,4% (1/41). Uma vaca que morreu após um curso clínico de 3 dias foi necropsiada. Não foram observadas lesões macroscópicas significativas, mas na histopatologia havia rumenite necrosupurativa aguda, multifocal, moderada, com colonização bacteriana e fúngica secundária, indicando acidose ruminal concomitante. Em análise cromatográfica de amostras de conteúdo ruminal e fígado deste bovino foram detectadas quantidades variáveis de etanol. Os dados do presente estudo indicam que a possibilidade de intoxicação por etanol deve ser considerada em bovinos com sinais neurológicos e digestivos alimentados com RUC quando a este acrescentado levedura de cerveja.(AU)


An outbreak of ethanol poisoning that affected a dairy cattle herd fed with the brewery by-product known as malt bagasse, wet brewery residue, malted barley waste or "barley". The outbreak began about 24 hours after a new product of the by-product was offered to cattle that had an alcoholic odor. Chromatographic and microbiological analysis of this by-product sample confirmed the presence of ethanol and Saccharomyces spp., respectively, indicating the addition of another by-product brewery, brewer's yeast or yeast. The main clinical signs observed were diarrhea, salivation, staggering gait and decubitus. Morbidity was 12.2% (5/41) and mortality was 2.4% (1/41). A cow that died after a 3-day of clinical course was necropsied. No significant macroscopic lesions were observed, but in the histopathology, there was acute, multifocal, moderate necrosupurative rumenitis with secondary bacterial and fungal colonization, indicating concomitant ruminal acidosis. In the chromatographic analysis of samples of rumen and liver contents of this bovine, variable amounts of ethanol were detected. The data from the present study indicate that the possibility of ethanol intoxication should be considered in cattle with neurological and digestive signs fed with RUC when added to brewer's yeast.(AU)


Subject(s)
Animals , Cattle , Seedlings/toxicity , Ethanol/toxicity , Alcoholic Intoxication/veterinary , Saccharomyces cerevisiae/metabolism , Cattle
10.
Braz. j. microbiol ; 48(4): 791-800, Oct.-Dec. 2017. graf
Article in English | LILACS | ID: biblio-889166

ABSTRACT

ABSTRACT Lignocellulose-derived inhibitors have negative effects on the ethanol fermentation capacity of Saccharomyces cerevisiae. In this study, the effects of eight typical inhibitors, including weak acids, furans, and phenols, on glucose and xylose co-fermentation of the recombinant xylose-fermenting flocculating industrial S. cerevisiae strain NAPX37 were evaluated by batch fermentation. Inhibition on glucose fermentation, not that on xylose fermentation, correlated with delayed cell growth. The weak acids and the phenols showed additive effects. The effect of inhibitors on glucose fermentation was as follows (from strongest to weakest): vanillin > phenol > syringaldehyde > 5-HMF > furfural > levulinic acid > acetic acid > formic acid. The effect of inhibitors on xylose fermentation was as follows (from strongest to weakest): phenol > vanillin > syringaldehyde > furfural > 5-HMF > formic acid > levulinic acid > acetic acid. The NAPX37 strain showed substantial tolerance to typical inhibitors and showed good fermentation characteristics, when a medium with inhibitor cocktail or rape straw hydrolysate was used. This research provides important clues for inhibitors tolerance of recombinant industrial xylose-fermenting S. cerevisiae.


Subject(s)
Saccharomyces cerevisiae/drug effects , Xylose/metabolism , Glucose/metabolism , Phenols/metabolism , Phenols/pharmacology , Saccharomyces cerevisiae/growth & development , Saccharomyces cerevisiae/genetics , Saccharomyces cerevisiae/metabolism , Acids/metabolism , Acids/pharmacology , Industrial Microbiology , Fermentation , Furans/metabolism , Furans/pharmacology
11.
Braz. j. microbiol ; 48(3): 537-543, July-Sept. 2017. graf
Article in English | LILACS | ID: biblio-889126

ABSTRACT

Abstract Metallothioneins are a superfamily of low-molecular-weight, cysteine (Cys)-rich proteins that are believed to play important roles in protection against metal toxicity and oxidative stress. The main purpose of this study was to investigate the effect of heterologous expression of a rice metallothionein isoform (OsMTI-1b) on the tolerance of Saccharomyces cerevisiae to Cd2+, H2O2 and ethanol stress. The gene encoding OsMTI-1b was cloned into p426GPD as a yeast expression vector. The new construct was transformed to competent cells of S. cerevisiae. After verification of heterologous expression of OsMTI-1b, the new strain and control were grown under stress conditions. In comparison to control strain, the transformed S. cerevisiae cells expressing OsMTI-1b showed more tolerance to Cd2+ and accumulated more Cd2+ ions when they were grown in the medium containing CdCl2. In addition, the heterologous expression of GST-OsMTI-1b conferred H2O2 and ethanol tolerance to S. cerevisiae cells. The results indicate that heterologous expression of plant MT isoforms can enhance the tolerance of S. cerevisiae to multiple stresses.


Subject(s)
Plant Proteins/genetics , Oryza/genetics , Saccharomyces cerevisiae/metabolism , Cadmium/metabolism , Gene Expression , Ethanol/metabolism , Hydrogen Peroxide/metabolism , Metallothionein/genetics , Plant Proteins/metabolism , Saccharomyces cerevisiae/genetics , Oxidative Stress , Protein Isoforms/genetics , Protein Isoforms/metabolism , Metallothionein/metabolism
12.
Braz. j. microbiol ; 48(3): 461-475, July-Sept. 2017. tab, graf
Article in English | LILACS | ID: biblio-889144

ABSTRACT

Abstract The application of high-potential thermotolerant yeasts is a key factor for successful ethanol production at high temperatures. Two hundred and thirty-four yeast isolates from Greater Mekong Subregion (GMS) countries, i.e., Thailand, The Lao People's Democratic Republic (Lao PDR) and Vietnam were obtained. Five thermotolerant yeasts, designated Saccharomyces cerevisiae KKU-VN8, KKU-VN20, and KKU-VN27, Pichia kudriavzevii KKU-TH33 and P. kudriavzevii KKU-TH43, demonstrated high temperature and ethanol tolerance levels up to 45 °C and 13% (v/v), respectively. All five strains produced higher ethanol concentrations and exhibited greater productivities and yields than the industrial strain S. cerevisiae TISTR5606 during high-temperature fermentation at 40 °C and 43 °C. S. cerevisiae KKU-VN8 demonstrated the best performance for ethanol production from glucose at 37 °C with an ethanol concentration of 72.69 g/L, a productivity of 1.59 g/L/h and a theoretical ethanol yield of 86.27%. The optimal conditions for ethanol production of S. cerevisiae KKU-VN8 from sweet sorghum juice (SSJ) at 40 °C were achieved using the Box-Behnken experimental design (BBD). The maximal ethanol concentration obtained during fermentation was 89.32 g/L, with a productivity of 2.48 g/L/h and a theoretical ethanol yield of 96.32%. Thus, the newly isolated thermotolerant S. cerevisiae KKU-VN8 exhibits a great potential for commercial-scale ethanol production in the future.


Subject(s)
Pichia/metabolism , Saccharomyces cerevisiae/metabolism , Ethanol/metabolism , Pichia/isolation & purification , Pichia/genetics , Pichia/chemistry , Asia, Southeastern , Saccharomyces cerevisiae/isolation & purification , Saccharomyces cerevisiae/genetics , Saccharomyces cerevisiae/chemistry , Sorghum/metabolism , Glucose/metabolism , Hot Temperature
13.
Braz. j. microbiol ; 48(3): 403-409, July-Sept. 2017. tab, graf
Article in English | LILACS | ID: biblio-889142

ABSTRACT

Abstract Very high gravity (VHG) technology was employed on industrial scale to produce ethanol from molasses (fermented) as well as by-products formation estimation. The effect of different Brix° (32, 36 and 40) air-flow rates (0.00, 0.20, 0.40, and 0.60 vvm) was studied on ethanol production. The maximum ethanol production was recorded to be 12.2% (v/v) at 40 Brix° with 0.2 vvm air-flow rate. At optimum level aeration and 40 Brix° VHG, the residual sugar level was recorded in the range of 12.5-18.5 g/L, whereas the viable cell count remained constant up to 50 h of fermentation and dry matter production increased with fermentation time. Both water and steam consumption reduced significantly under optimum conditions of Brix° and aeration rate with compromising the ethanol production. Results revealed VHG with continuous air flow is viable technique to reduce the ethanol production cost form molasses at commercial scale.


Subject(s)
Chick Embryo , Ethanol/metabolism , Industrial Microbiology/methods , Molasses/microbiology , Saccharomyces cerevisiae/metabolism , Fermentation , Hypergravity , Industrial Microbiology/instrumentation , Molasses/analysis , Molasses/economics , Saccharomyces cerevisiae/genetics
14.
Braz. j. microbiol ; 48(3): 592-601, July-Sept. 2017. tab, graf
Article in English | LILACS | ID: biblio-889150

ABSTRACT

Abstract The aim of this study was to develop a kefir apple-based vinegar and evaluate this fermentation process using new methodology with Biospeckle Laser. Brazilian kefir grains were inoculated in apple must for vinegar production. In this study, the microbial community present in kefir, and correspondent vinegar, was investigated using Matrix Assisted Laser Desorption/Ionization - Time of Flight Mass Spectrometry (MALDI-TOF MS) technique. Saccharomyces cerevisiae, Lactobacillus paracasei, Lactobacillus plantarum, Acetobacter pasteurianus and Acetobacter syzygii were the microbial species identified. S. cerevisiae, L. plantarum, A. pasteurianus and A. syzygii were found in smaller quantities at the beginning of the alcoholic fermentation, but were found throughout the alcoholic and acetic fermentation. Kefir grains were able to utilize apple must as substrate to produce ethanol, and acetic acid. Acetate, volatile alcohols and aldehydes in the vinegar-based kefir were also produced. The yield of acetic acid in the kefir vinegars was ∼79%. The acetic acid concentration was ∼41 g L-1, reaching the required standard for the Brazilian legislation accepts it as vinegar (4.0% acetic acid). Kefir vinegar showed good acceptance in the sensory analysis. The technology proposed here is novel by the application of immobilized-cell biomass (kefir grains) providing a mixed inocula and eliminating the use of centrifuge at the end of the fermentative process. This step will save energy demand and investment. This is the first study to produce apple vinegar using kefir grains.


Subject(s)
Humans , Alcoholic Beverages/microbiology , Kefir/analysis , Malus/microbiology , Acetic Acid/analysis , Acetic Acid/metabolism , Acetobacter/isolation & purification , Acetobacter/metabolism , Biodiversity , Brazil , Ethanol/analysis , Ethanol/metabolism , Fermentation , Food Handling , Kefir/microbiology , Lactobacillus/isolation & purification , Lactobacillus/metabolism , Malus/metabolism , Saccharomyces cerevisiae/isolation & purification , Saccharomyces cerevisiae/metabolism , Taste
15.
Braz. j. microbiol ; 48(2): 268-274, April.-June 2017. tab, graf
Article in English | LILACS | ID: biblio-839369

ABSTRACT

Abstract Strains of Saccharomyces cerevisiae may display characteristics that are typical of rough-type colonies, made up of cells clustered in pseudohyphal structures and comprised of daughter buds that do not separate from the mother cell post-mitosis. These strains are known to occur frequently in fermentation tanks with significant lower ethanol yield when compared to fermentations carried out by smooth strains of S. cerevisiae that are composed of dispersed cells. In an attempt to delineate genetic and phenotypic differences underlying the two phenotypes, this study analysed 10 microsatellite loci of 22 S. cerevisiae strains as well as stress resistance towards high concentrations of ethanol and glucose, low pH and cell sedimentation rates. The results obtained from the phenotypic tests by Principal-Component Analysis revealed that unlike the smooth colonies, the rough colonies of S. cerevisiae exhibit an enhanced resistance to stressful conditions resulting from the presence of excessive glucose and ethanol and high sedimentation rate. The microsatellite analysis was not successful to distinguish between the colony phenotypes as phenotypic assays. The relevant industrial strain PE-2 was observed in close genetic proximity to rough-colony although it does not display this colony morphology. A unique genetic pattern specific to a particular phenotype remains elusive.


Subject(s)
Saccharomyces cerevisiae/physiology , Saccharomyces cerevisiae/genetics , Genetic Variation , Microsatellite Repeats , Ethanol/metabolism , Phenotype , Saccharomyces cerevisiae/classification , Saccharomyces cerevisiae/metabolism , Stress, Physiological , Genotype , Glucose/metabolism , Hydrogen-Ion Concentration
16.
Electron. j. biotechnol ; 26: 84-92, Mar. 2017. graf, tab
Article in English | LILACS | ID: biblio-1008992

ABSTRACT

Background: Fermentation process development has been very important for efficient ethanol production. Improvement of ethanol production efficiency from sweet sorghum juice (SSJ) under normal gravity (NG, 160 g/L of sugar), high gravity (HG, 200 and 240 g/L of sugar) and very high gravity (VHG, 280 and 320 g/L of sugar) conditions by nutrient supplementation and alternative feeding regimes (batch and fed-batch systems) was investigated using a highly ethanol-tolerant strain, Saccharomyces cerevisiae NP01. Results: In the batch fermentations without yeast extract, HG fermentation at 200 g/L of sugar showed the highest ethanol concentration (PE, 90.0 g/L) and ethanol productivity (QE, 1.25 g/L·h). With yeast extract supplementation (9 g/L), the ethanol production efficiency increased at all sugar concentrations. The highest PE (112.5 g/L) and QE (1.56 g/L·h) were observed with the VHG fermentation at 280 g/L of sugar. In the fed-batch fermentations, two feeding regimes, i.e., stepwise and continuous feedings, were studied at sugar concentrations of 280 g/L. Continuous feeding gave better results with the highest PE and QE of 112.9 g/L and 2.35 g/L·h, respectively, at a feeding time of 9 h and feeding rate of 40 g sugar/h. Conclusions: In the batch fermentation, nitrogen supplementation resulted in 4 to 32 g/L increases in ethanol production, depending on the initial sugar level in the SSJ. Under the VHG condition, with sufficient nitrogen, the fed-batch fermentation with continuous feeding resulted in a similar PE and increased QP by 51% compared to those in the batch fermentation.


Subject(s)
Sorghum/metabolism , Ethanol/metabolism , Biofuels , Fermentation , Saccharomyces cerevisiae/metabolism , Dietary Supplements , Sorghum/chemistry , Batch Cell Culture Techniques , Gravitation , Nitrogen
17.
Electron. j. biotechnol ; 19(4): 81-89, July 2016. ilus
Article in English | LILACS | ID: lil-793957

ABSTRACT

Background: Antithrombin III (ATIII) is a protein that inhibits abnormal blood clots (or coagulation) by breaking down thrombin and factor Xa. ATIII helps to keep a healthy balance between hemorrhage and coagulation. The present work demonstrated the production, purification and characterization of recombinant human antithrombin (rhAT) from yeast Saccharomyces cerevisiae BY4741 was demonstrated. After expression of rhAT by S. cerevisiae, the biomass and rhAT concentration were analyzed through fed-batch fermentation process. Results: In fed-batch fermentation, the biomass (maximum cell dry weight of 11.2 g/L) and rhAT concentration (312 mg/L) of the expressed rhAT were achieved at 84 h of cultivation time. The maximum cell lysis efficiency (99.89%) was found at 8 s sonication pulse and 7 mL lysis buffer volume. The rhAT protein solution was concentrated and partially purified using cross-flow filtration with the recovery yield and purity of 95 and 94%, respectively. The concentrated solution was further purified by the single step ion exchange chromatography with the recovery yield and purity of 55 and >98%, respectively. The purified rhAT was characterized by various analytical techniques, such as RP-HPLC, FT-IR, CD, SDS-PAGE, western blotting, and Liquid chromatography mass spectrometry (LC-MS) analysis. The biological activity of rhAT was analyzed as heparin cofactor to meet the therapeutic grade applications. Conclusions: The simple, cost-effective and economically viable nature of the process used in the present study for the production of rhAT will be highly beneficial for the healthcare sector. This may also be used to produce other value-added therapeutic recombinant proteins expressed in S. cerevisiae, with greater effectiveness and ease.


Subject(s)
Saccharomyces cerevisiae/metabolism , Recombinant Proteins/isolation & purification , Recombinant Proteins/biosynthesis , Antithrombin III/isolation & purification , Antithrombin III/biosynthesis , Blotting, Western , Chromatography, High Pressure Liquid , Bioreactors , Fermentation , Filtration
18.
Braz. j. microbiol ; 47(2): 452-460, Apr.-June 2016. tab, graf
Article in English | LILACS | ID: lil-780816

ABSTRACT

Abstract A high concentration of histamine, one of the biogenic amines (BAs) usually found in fermented foods, can cause undesirable physiological side effects in sensitive humans. The objective of this study is to isolate indigenous Acetobacter strains from naturally fermented Bokbunja vinegar in Korea with reduced histamine production during starter fermentation. Further, we examined its physiological and biochemical properties, including BA synthesis. The obtained strain MBA-77, identified as Acetobacter aceti by 16S rDNA homology and biochemical analysis and named A. aceti MBA-77. A. aceti MBA-77 showed optimal acidity % production at pH 5; the optimal temperature was 25 °C. When we prepared and examined the BAs synthesis spectrum during the fermentation process, Bokbunja wine fermented with Saccharomyces cerevisiae showed that the histamine concentration increased from 2.72 of Bokbunja extract to 5.29 mg/L and cadaverine and dopamine was decreased to 2.6 and 10.12 mg/L, respectively. Bokbunja vinegar prepared by A. aceti MBA-77 as the starter, the histamine concentration of the vinegar preparation step was decreased up to 3.66 mg/L from 5.29 mg/L in the wine preparation step. To our knowledge, this is the first report to demonstrate acetic acid bacteria isolated from Bokbunja seed vinegar with low spectrum BA and would be useful for wellbeing vinegar preparation.


Subject(s)
Wine/analysis , Biogenic Amines/analysis , Acetobacter/metabolism , Histamine/metabolism , Rubus/microbiology , Saccharomyces cerevisiae/metabolism , Wine/microbiology , Acetobacter/isolation & purification , Acetobacter/genetics , Histamine/analysis , Acetic Acid/analysis , Acetic Acid/metabolism , Fermentation , Rubus/metabolism , Food Microbiology
19.
Braz. j. microbiol ; 47(1): 136-142, Jan.-Mar. 2016. tab, graf
Article in English | LILACS | ID: lil-775098

ABSTRACT

Abstract The kinetics of an extracellular β-D-fructofuranosidase fructohydrolase production by Saccharomyces cerevisiae in a chemically defined medium, i.e., sucrose peptone agar yeast extract at pH 6, was investigated. The wild-type was treated with a chemical mutagen, methyl methane sulfonate. Among the six mutants isolated, methyl methane sulfonate-V was found to be a better enzyme producing strain (52 ± 2.4a U/mL). The maximum production (74 ± 3.1a U/mL) was accomplished after at 48 h (68 ± 2.7a mg/mL protein). The mutants were stabilized at low levels of 5-fluoro-cytocine and the viable ones were further processed for optimization of cultural conditions and nutritional requirements. The sucrose concentration, incubation period and pH were optimized to be 30 g/L, 28 °C, and 6.5, respectively. The methyl methane sulfonate-V exhibited an improvement of over 10 folds in enzyme production when 5 g/L ammonium sulfate was used as a nitrogen source. Thin layer chromatography and high-performance liquid chromatography analysis illustrated the optimal enzyme activity supported by the higher rate of hydrolysis of sucrose into monosaccharides, particularly α-D-glucose and β-D-fructose. The values for Qp (2 ± 0.12c U/mL/h) and Yp/s (4 ± 1.24b U/g) of the mutant were considerably increased in comparison with other yeast strains (both isolates and viable mutants). The mutant could be exploited for enzyme production over a wider temperature range (26–34 °C), with significantly high enzyme activity (LSD 0.048, HS) at the optimal temperature.


Subject(s)
Mutation , Saccharomyces cerevisiae/growth & development , Saccharomyces cerevisiae/metabolism , beta-Fructofuranosidase/biosynthesis , Chromatography, High Pressure Liquid , Chromatography, Thin Layer , Culture Media/chemistry , Hydrogen-Ion Concentration , Hydrolysis , Mutagenesis , Mutagens/metabolism , Serratia , Saccharomyces cerevisiae/genetics , Sucrose/metabolism , Sulfinic Acids/metabolism , Temperature
20.
Arq. bras. med. vet. zootec ; 67(6): 1711-1720, nov.-dez. 2015. tab
Article in Portuguese | LILACS | ID: lil-768131

ABSTRACT

Objetivou-se determinar a temperatura e o tempo de secagem por rolos rotativos, aos quais a, levedura de cana-de-açúcar é submetida que permitam seu melhor aproveitamento energético por galinhas poedeiras e frangos de corte. Para isso foram realizados três ensaios de metabolismo para determinar os valores de energia metabolizável aparente (EMA), aparente corrigida para nitrogênio (EMAn) e os coeficientes de metabolizabilidade aparente da matéria seca (CMMS) e da energia bruta (CMEB). O primeiro ensaio foi conduzido com galinhas poedeiras (E1), o segundo com frangos de corte (E2) em crescimento e o terceiro com frangos de corte em diferentes idades (E3)...


This study aimed to determine the temperature and drying time through rotative rolls, that sugar cane yeast is subjected to in order to allow best energy utilization by laying hens and broilers. Three metabolism trials were conducted to determine the values of apparent metabolizable energy (AME) and apparent corrected for nitrogen balance (AMEn), coefficient of apparent metabolizable dry matter (CAMDM) and gross energy (CAMGE). The first experiment was conducted with laying hens (E1), the second with broilers (E2) in growth and the third with broilers at different ages (E3)...


Subject(s)
Animals , Food Preservation/methods , Diet/veterinary , Saccharomyces cerevisiae/metabolism , Poultry/metabolism , Chickens/metabolism , Yeasts/metabolism
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