scholarly journals Observation on the refermentation of sweet Botrytis-affected wines

OENO One ◽  
2004 ◽  
Vol 38 (3) ◽  
pp. 181
Author(s):  
Benoit Divol ◽  
Aline Lonvaud-Funel
Keyword(s):  
Saccharomyces Cerevisiae ◽  
Alcoholic Fermentation ◽  
Species Selection ◽  
Vbnc State ◽  
Strain Diversity ◽  
Long Time ◽  
Resistant Strains ◽  
Binding Power ◽  
High Degree ◽  
Sweet Wine

<p style="text-align: justify;"><em>Botrytis</em>-affected wines are microbiologically unstable. Fermentation can occasionally occur during maturing time or bottle-ageing. However, wines which undergo refermentations seem to be free of yeasts. This work deals with microbial aspects and ecology of wines during alcoholic fermentation, then during refermentation. Yeast survival after stopping the alcoholic fermentation by sulphur dioxide addition is considered. Results suggest that most yeasts could survive in sweet wine under the viable but non-culturable (VBNC) state. The increase of acetaldehyde these wines in response to sulfiting is known for long time but not the conditions of its formation. In this work we show that it is probably the key of the refermentation phenomenon, through the increase of the binding power. During maturing successive cycles occur: acetaldehyde consumption, revival, death and/or new enter into VBNC state accompanied by acetaldehyde formation which increased the binding power. Then as molecular SO2 became too low, yeasts could start a new fermentation. In this work, an ecology study was also undertaken, to understand the effect of SO2 on yeast biodiversity. Most of the fermentative yeasts could survive especially <em>Saccharomyces cerevisiae</em> and <em>Zygosaccharomyces </em>sp., together with other yeast genera. In regard to <em>Saccharomyces cerevisiae</em> only which is often responsible for the refermentation phenomenon, this work concluded on the decrease of strain diversity to only one or two strains, in spite of the high degree of diversity during the alcoholic fermentation. The intra-species selection probably conducted to sulfite-resistant strains.</p>

scholarly journals Impact of some components on Bordeaux roses and clairets aroma

OENO One ◽  
2001 ◽  
Vol 35 (2) ◽  
pp. 99
Author(s):  
Marie-Laure Murat ◽  
Takatoshi Tominaga ◽  
Denis Dubourdieu
Keyword(s):  
Saccharomyces Cerevisiae ◽  
Ethyl Acetate ◽  
Alcoholic Fermentation ◽  
Isoamyl Acetate ◽  
Cabernet Sauvignon ◽  
Sensorial Analysis ◽  
Cabernet Franc ◽  
Yeast Strains ◽  
Long Time ◽  
Rosé Wine

<p style="text-align: justify;">Twenty rose and ten claret A.O.C. Bordeaux wines made from Cabernet Sauvignon, Cabernet franc and Merlot grapes were separately tasted by the same jury of ten professionals. They were asked to classify the wines according to the intensity of the fruity character. The fruitiest sample was given first rank. The wines’ bdamascenone, b-ionone, phenyl-2-ethanol, isoamyl acetate, phenyl-ethyl acetate (APE), 3-mercaptohexan-1-ol (3MH) and 3-mercaptohexyl acetate (A3MH) contents were also measured. The higher the latter three compounds' values, the higher the wines’ fruity character. Highly significant correlation were found between the sensorial analysis results and these compounds contents. In order to confirm the 3MH, A3MH and APE contribution to the fruity aroma of rose wines, a tasting has been carried out. For this, these three compounds were added to a rose wine up to the concentrations found in the wine judged the fruitiest by the tasters. 100 % of the tasters identified the supplemented glasses, and 90 % prefered the supplemented wine. This second experiment clearly demonstrate that 3MH, A3MH and APE can be considered key components of Bordeaux rose wines’ fruity aroma.</p><p style="text-align: justify;">The production of APE by yeast has been known for a long time. The 3MH is present in must under cysteinylated precursor form. The transformation of the precursor into aroma is made by the Saccharomyces cerevisiae yeasts during alcoholic fermentation. Thus the choice of yeast strains has a decisive impact on the fruity aroma of Bordeaux rose and claret wines.</p>

Achieving Procedure of a Kinetic Model to Predict the Influence of the Process Global Temperature on a Technological Alcoholic Fermentation II. An Arrhenius type Kinetic Model

2008 ◽  
Vol 59 (4) ◽  
Author(s):  
Neculai Catalin Lungu ◽  
Maria Alexandroaei
Keyword(s):  
Experimental Data ◽  
Saccharomyces Cerevisiae ◽  
Kinetic Model ◽  
Economic Efficiency ◽  
Fermentation Process ◽  
Alcoholic Fermentation ◽  
Global Temperature ◽  
Medium Temperature ◽  
Biotechnological Process

The aim of the present work is to offer a practical methodology to realise an Arrhenius type kinetic model for a biotechnological process of alcoholic fermentation based on the Saccharomyces cerevisiae yeast. Using the experimental data we can correlate the medium temperature of fermentation with the time needed for a fermentation process under imposed conditions of economic efficiency.

scholarly journals Saccharomyces cerevisiae Fermentation of 28 Barley and 12 Oat Cultivars

Fermentation ◽  
2021 ◽  
Vol 7 (2) ◽  
pp. 59
Author(s):  
Timothy J. Tse ◽  
Daniel J. Wiens ◽  
Jianheng Shen ◽  
Aaron D. Beattie ◽  
Martin J. T. Reaney
Keyword(s):  
Saccharomyces Cerevisiae ◽  
Acetic Acid ◽  
Lactic Acid ◽  
Succinic Acid ◽  
Alcoholic Fermentation ◽  
Ethanol Yield ◽  
Cereal Crops ◽  
Fermentation Products ◽  
Barley Cultivars ◽  
Oat Cultivars

As barley and oat production have recently increased in Canada, it has become prudent to investigate these cereal crops as potential feedstocks for alcoholic fermentation. Ethanol and other coproduct yields can vary substantially among fermented feedstocks, which currently consist primarily of wheat and corn. In this study, the liquified mash of milled grains from 28 barley (hulled and hull-less) and 12 oat cultivars were fermented with Saccharomyces cerevisiae to determine concentrations of fermentation products (ethanol, isopropanol, acetic acid, lactic acid, succinic acid, α-glycerylphosphorylcholine (α-GPC), and glycerol). On average, the fermentation of barley produced significantly higher amounts of ethanol, isopropanol, acetic acid, succinic acid, α-GPC, and glycerol than that of oats. The best performing barley cultivars were able to produce up to 78.48 g/L (CDC Clear) ethanol and 1.81 g/L α-GPC (CDC Cowboy). Furthermore, the presence of milled hulls did not impact ethanol yield amongst barley cultivars. Due to its superior ethanol yield compared to oats, barley is a suitable feedstock for ethanol production. In addition, the accumulation of α-GPC could add considerable value to the fermentation of these cereal crops.

scholarly journals Oenological Potential of Autochthonous Saccharomyces cerevisiae Yeast Strains from the Greek Varieties of Agiorgitiko and Moschofilero

Beverages ◽  
2021 ◽  
Vol 7 (2) ◽  
pp. 27
Author(s):  
Dimitrios Kontogiannatos ◽  
Vicky Troianou ◽  
Maria Dimopoulou ◽  
Polydefkis Hatzopoulos ◽  
Yorgos Kotseridis
Keyword(s):  
Saccharomyces Cerevisiae ◽  
Alcoholic Fermentation ◽  
Ethanol Tolerance ◽  
Random Amplified Polymorphic Dna ◽  
Yeast Strains ◽  
Rapd Pcr ◽  
Autochthonous Yeast ◽  
Polymerase Chain ◽  
Grape Varieties ◽  
H2s Production

Nemea and Mantinia are famous wine regions in Greece known for two indigenous grape varieties, Agiorgitiko and Moschofilero, which produce high quality PDO wines. In the present study, indigenous Saccharomyces cerevisiae yeast strains were isolated and identified from spontaneous alcoholic fermentation of Agiorgitiko and Moschofilero musts in order to evaluate their oenological potential. Random amplified polymorphic DNA-polymerase chain reaction (RAPD-PCR) recovered the presence of five distinct profiles from a total of 430 yeast isolates. The five obtained strains were evaluated at microvinifications trials and tested for basic oenological and biochemical parameters including sulphur dioxide and ethanol tolerance as well as H2S production in sterile grape must. The selected autochthonous yeast strains named, Soi2 (Agiorgitiko wine) and L2M (Moschofilero wine), were evaluated also in industrial (4000L) fermentations to assess their sensorial and oenological characteristics. The volatile compounds of the produced wines were determined by GC-FID. Our results demonstrated the feasibility of using Soi2 and L2M strains in industrial fermentations for Agiorgitiko and Moschofilero grape musts, respectively.

scholarly journals Molecular Basis of Fructose Utilization by the Wine Yeast Saccharomyces cerevisiae: a Mutated HXT3 Allele Enhances Fructose Fermentation

2007 ◽  
Vol 73 (8) ◽  
pp. 2432-2439 ◽  
Author(s):  
Carole Guillaume ◽  
Pierre Delobel ◽  
Jean-Marie Sablayrolles ◽  
Bruno Blondin
Keyword(s):  
Saccharomyces Cerevisiae ◽  
Molecular Basis ◽  
Alcoholic Fermentation ◽  
Wine Yeast ◽  
Glycolytic Flux ◽  
Hexose Transporter ◽  
Wine Yeasts ◽  
Yeast Saccharomyces Cerevisiae ◽  
High Fructose ◽  
Fructose Fermentation

ABSTRACT Fructose utilization by wine yeasts is critically important for the maintenance of a high fermentation rate at the end of alcoholic fermentation. A Saccharomyces cerevisiae wine yeast able to ferment grape must sugars to dryness was found to have a high fructose utilization capacity. We investigated the molecular basis of this enhanced fructose utilization capacity by studying the properties of several hexose transporter (HXT) genes. We found that this wine yeast harbored a mutated HXT3 allele. A functional analysis of this mutated allele was performed by examining expression in an hxt1-7Δ strain. Expression of the mutated allele alone was found to be sufficient for producing an increase in fructose utilization during fermentation similar to that observed in the commercial wine yeast. This work provides the first demonstration that the pattern of fructose utilization during wine fermentation can be altered by expression of a mutated hexose transporter in a wine yeast. We also found that the glycolytic flux could be increased by overexpression of the mutant transporter gene, with no effect on fructose utilization. Our data demonstrate that the Hxt3 hexose transporter plays a key role in determining the glucose/fructose utilization ratio during fermentation.

scholarly journals Preparation and Antimicrobial Activity of Chitosan and Its Derivatives: A Concise Review

Molecules ◽  
2021 ◽  
Vol 26 (12) ◽  
pp. 3694
Author(s):  
Luminita Georgeta Confederat ◽  
Cristina Gabriela Tuchilus ◽  
Maria Dragan ◽  
Mousa Sha’at ◽  
Oana Maria Dragostin
Keyword(s):  
Antimicrobial Activity ◽  
Low Cost ◽  
Hydroxyl Groups ◽  
Pharmacological Properties ◽  
Natural Polymers ◽  
Economic Sectors ◽  
Physico Chemical ◽  
Long Time ◽  
Resistant Strains ◽  
Strength And Durability

Despite the advantages presented by synthetic polymers such as strength and durability, the lack of biodegradability associated with the persistence in the environment for a long time turned the attention of researchers to natural polymers. Being biodegradable, biopolymers proved to be extremely beneficial to the environment. At present, they represent an important class of materials with applications in all economic sectors, but also in medicine. They find applications as absorbers, cosmetics, controlled drug delivery, tissue engineering, etc. Chitosan is one of the natural polymers which raised a strong interest for researchers due to some exceptional properties such as biodegradability, biocompatibility, nontoxicity, non-antigenicity, low-cost and numerous pharmacological properties as antimicrobial, antitumor, antioxidant, antidiabetic, immunoenhancing. In addition to this, the free amino and hydroxyl groups make it susceptible to a series of structural modulations, obtaining some derivatives with different biomedical applications. This review approaches the physico-chemical and pharmacological properties of chitosan and its derivatives, focusing on the antimicrobial potential including mechanism of action, factors that influence the antimicrobial activity and the activity against resistant strains, topics of great interest in the context of the concern raised by the available therapeutic options for infections, especially with resistant strains.

scholarly journals CRISPR-Cas9: A Powerful Tool to Efficiently Engineer Saccharomyces cerevisiae

Life ◽  
2020 ◽  
Vol 11 (1) ◽  
pp. 13
Author(s):  
João Rainha ◽  
Joana L. Rodrigues ◽  
Lígia R. Rodrigues
Keyword(s):  
Saccharomyces Cerevisiae ◽  
Yeast Genome ◽  
Specific Method ◽  
Complex Processes ◽  
Biological Studies ◽  
Precise Tool ◽  
Long Time ◽  
Gene Knockouts ◽  
Heterologous Pathway ◽  
A Current

Saccharomyces cerevisiae has been for a long time a common model for fundamental biological studies and a popular biotechnological engineering platform to produce chemicals, fuels, and pharmaceuticals due to its peculiar characteristics. Both lines of research require an effective editing of the native genetic elements or the inclusion of heterologous pathways into the yeast genome. Although S. cerevisiae is a well-known host with several molecular biology tools available, a more precise tool is still needed. The clustered, regularly interspaced, short palindromic repeats–associated Cas9 (CRISPR-Cas9) system is a current, widespread genome editing tool. The implementation of a reprogrammable, precise, and specific method, such as CRISPR-Cas9, to edit the S. cerevisiae genome has revolutionized laboratory practices. Herein, we describe and discuss some applications of the CRISPR-Cas9 system in S. cerevisiae from simple gene knockouts to more complex processes such as artificial heterologous pathway integration, transcriptional regulation, or tolerance engineering.

scholarly journals Recombinant Diploid Saccharomyces cerevisiae Strain Development for Rapid Glucose and Xylose Co-Fermentation

Fermentation ◽  
2018 ◽  
Vol 4 (3) ◽  
pp. 59 ◽  
Author(s):  
Tingting Liu ◽  
Shuangcheng Huang ◽  
Anli Geng
Keyword(s):  
Saccharomyces Cerevisiae ◽  
Alcoholic Fermentation ◽  
Ethanol Yield ◽  
Xylose Isomerase ◽  
Cost Effective ◽  
Xylose Utilization ◽  
Yeast Strains ◽  
Multiple Copies ◽  
Biomass Sugars ◽  
Sugar Conversion

Cost-effective production of cellulosic ethanol requires robust microorganisms for rapid co-fermentation of glucose and xylose. This study aims to develop a recombinant diploid xylose-fermenting Saccharomyces cerevisiae strain for efficient conversion of lignocellulosic biomass sugars to ethanol. Episomal plasmids harboring codon-optimized Piromyces sp. E2 xylose isomerase (PirXylA) and Orpinomyces sp. ukk1 xylose (OrpXylA) genes were constructed and transformed into S. cerevisiae. The strain harboring plasmids with tandem PirXylA was favorable for xylose utilization when xylose was used as the sole carbon source, while the strain harboring plasmids with tandem OrpXylA was beneficial for glucose and xylose cofermentation. PirXylA and OrpXylA genes were also individually integrated into the genome of yeast strains in multiple copies. Such integration was beneficial for xylose alcoholic fermentation. The respiration-deficient strain carrying episomal or integrated OrpXylA genes exhibited the best performance for glucose and xylose co-fermentation. This was partly attributed to the high expression levels and activities of xylose isomerase. Mating a respiration-efficient strain carrying the integrated PirXylA gene with a respiration-deficient strain harboring integrated OrpXylA generated a diploid recombinant xylose-fermenting yeast strain STXQ with enhanced cell growth and xylose fermentation. Co-fermentation of 162 g L−1 glucose and 95 g L−1 xylose generated 120.6 g L−1 ethanol in 23 h, with sugar conversion higher than 99%, ethanol yield of 0.47 g g−1, and ethanol productivity of 5.26 g L−1·h−1.

scholarly journals SENSITIVITY OF TRYPTOPHAN, TYROSINE AND PHENYLALANINE MUTANTS OF SACCHAROMYCES CEREVISIAE TO PHENETHYL ALCOHOL

Genetics ◽  
1983 ◽  
Vol 104 (2) ◽  
pp. 235-240
Author(s):  
James H Meade ◽  
Thomas R Manney
Keyword(s):  
Saccharomyces Cerevisiae ◽  
Cell Membrane ◽  
Growth Inhibition ◽  
Membrane Structure ◽  
Phenethyl Alcohol ◽  
Resistant Strains

ABSTRACT Phenethyl alcohol inhibits the growth of many microorganisms. It is believed that the growth inhibition is mediated by its effect on the cell membrane. Differences between sensitive and resistant strains are suggested to be due to alterations in membrane structure. We report that, in some strains, an unexpected relationship exists between auxotrophy for tryptophan, tyrosine and phenylalanine and sensitivity to phenethyl alcohol.

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