Biotechnological Approaches to Lowering the Ethanol Yield during Wine Fermentation

One of the most prominent consequences of global climate warming for the wine industry is a clear increase of the sugar content in grapes, and thus the alcohol level in wines. Among the several approaches to address this important issue, this review focuses on biotechnological solutions, mostly relying on the selection and improvement of wine yeast strains for reduced ethanol yields. Other possibilities are also presented. Researchers are resorting to both S. cerevisiae and alternative wine yeast species for the lowering of alcohol yields. In addition to the use of selected strains under more or less standard fermentation conditions, aerobic fermentation is increasingly being explored for this purpose. Genetic improvement is also playing a role in the development of biotechnological tools to counter the increase in the wine alcohol levels. The use of recombinant wine yeasts is restricted to research, but its contribution to the advancement of the field is still relevant. Furthermore, genetic improvement by non-GMO approaches is providing some interesting results, and will probably result in the development of commercial yeast strains with a lower alcohol yield in the near future. The optimization of fermentation processes using natural isolates is, anyway, the most probable source of advancement in the short term for the production of wines with lower alcohol contents.

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The Fitness Advantage of Commercial Wine Yeasts in Relation to the Nitrogen Concentration, Temperature, and Ethanol Content under Microvinification Conditions

Applied and Environmental Microbiology ◽

10.1128/aem.03405-13 ◽

2013 ◽

Vol 80 (2) ◽

pp. 704-713 ◽

Cited By ~ 19

Author(s):

Estéfani García-Ríos ◽

Alicia Gutiérrez ◽

Zoel Salvadó ◽

Francisco Noé Arroyo-López ◽

José Manuel Guillamon

Keyword(s):

Abiotic Factors ◽

Nitrogen Concentration ◽

Wine Yeast ◽

Wine Industry ◽

Wine Yeasts ◽

Simple Method ◽

Fitness Advantage ◽

Yeast Strains ◽

Industrial Strains ◽

Nitrogen Concentrations

ABSTRACTThe effect of the main environmental factors governing wine fermentation on the fitness of industrial yeast strains has barely received attention. In this study, we used the concept of fitness advantage to measure how increasing nitrogen concentrations (0 to 200 mg N/liter), ethanol (0 to 20%), and temperature (4 to 45°C) affects competition among four commercial wine yeast strains (PDM, ARM, RVA, and TTA). We used a mathematical approach to model the hypothetical time needed for the control strain (PDM) to out-compete the other three strains in a theoretical mixed population. The theoretical values obtained were subsequently verified by competitive mixed fermentations in both synthetic and natural musts, which showed a good fit between the theoretical and experimental data. Specifically, the data show that the increase in nitrogen concentration and temperature values improved the fitness advantage of the PDM strain, whereas the presence of ethanol significantly reduced its competitiveness. However, the RVA strain proved to be the most competitive yeast for the three enological parameters assayed. The study of the fitness of these industrial strains is of paramount interest for the wine industry, which uses them as starters of their fermentations. Here, we propose a very simple method to model the fitness advantage, which allows the prediction of the competitiveness of one strain with respect to different abiotic factors.

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The genetic improvement of grapevine cultivars and wine yeast strains: Novel approaches to the ancient art of winemaking

Suid-Afrikaanse Tydskrif vir Natuurwetenskap en Tegnologie ◽

10.4102/satnt.v22i1.208 ◽

2003 ◽

Vol 22 (1) ◽

pp. 31-43

Author(s):

I. S. Pretorius

Keyword(s):

Wine Yeast ◽

Wine Industry ◽

Market Demand ◽

Wine Production ◽

Yeast Strains ◽

Quantum Leap ◽

Grape Quality ◽

The Cost ◽

Grape Varieties ◽

Grape Cultivars

The widening gap between wine production and wine consumption, the shift of consumer preferences away from basic commodity wine to top quality wine, and the gruelling competition brought about by economic globalisation call for a total revolution in the magical world of wine. In the process of transforming the wine industry from a production-driven industry to a market-orientated enterprise, there is an increasing dependence on, amongst others, biotechnological innovation to launch the wine industry with a quantum leap across the formidable market challenges of the 21st century. Market-orientated designer grape cultivars and wine yeast strains are currently being genetically programmed with surgical precision for the cost-competitive production of high quality grapes and wine with relatively minimal resource inputs and a low environmental impact. With regard to Grapevine Biotechnology, this entails the establishment of stress tolerant and disease resistant varieties of Vitis vinifera with increased productivity, efficiency, sustainability and environmental friendliness, especially regarding improved pest and disease control, water use efficiency and grape quality. With regard to Wine Yeast Biotechnology, the emphasis is on the development of Saccharomyces cerevisiae strains with improved fermentation, processing and biopreservation abilities, and capacities for an increase in the wholesomeness and sensory quality of wine. The successful commercialisation of transgenic grape cultivars and wine yeasts depends on a number of scientific, technical, safety, ethical, legal, economic and marketing factors, and it therefore will be unwise to entertain high expectations in the short term. However, in the light of the phenomenal potential advantages of tailor-made grape varieties and yeast strains, it would be equally self-destructive in the long term if this strategically important “life insurance policy” is not taken out by the wine industry. This overview highlights the most important examples of the way in which V. vinifera grape varieties and S. cerevisiae wine yeast strains are currently being designed with surgical precision on the basis of market demand for the cost-effective, sustainable and environmentally friendly production of healthy, top quality grapes and wine.

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Biotechnological processes for regulating the quality and safety of wine products

BIO Web of Conferences ◽

10.1051/bioconf/20213406007 ◽

2021 ◽

Vol 34 ◽

pp. 06007

Author(s):

Olga Sheludko ◽

Nataliya Ageeva

Keyword(s):

Wine Yeast ◽

Developed Countries ◽

Wine Industry ◽

Oxidative Enzymes ◽

Industrial Complex ◽

Quality And Safety ◽

Successful Development ◽

Wine Production ◽

Yeast Strains ◽

Biotechnological Processes

The production of a competitive wine industry in Russia is an important task for the successful development of the country’s agro-industrial complex. The purpose of this research is to consider the ways of harmonious development of competitive Russian winemaking, based on the advanced bioecotechnologies of developed countries. This paper presents biotechnological processes and classes of enzymes or individual representatives. Established that both the enzymes of the grape and the enzyme systems of wine yeast are involved in the processes of wine production. During delivery of grapes for processing, means of inactivation of the activity of oxidative enzymes such as sulfur dioxide, liquid nitrogen, carbon dioxide should be used. Improvement and acceleration of clarification of grape must have to be done with the use of pectinesterases, polymethylgalacturonases, polygalacturonases, pectin transeliminases. In order to obtain wines stability to protein turbidity, the use of the technology of two-stage fermentation with deep protein transformation is recommended. Depending on the tasks of malolactic fermentation (MF) or its prevention, yeast strains that prevent the development of MF and strains that support the development of MF have been isolated. A relationship between the content of various groups of phenolic compounds and the activity of MF was established.

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Application of yeast with reduced alcohol yield for sparkling wine production

BIO Web of Conferences ◽

10.1051/bioconf/20191202021 ◽

2019 ◽

Vol 12 ◽

pp. 02021 ◽

Cited By ~ 1

Author(s):

M. Schmitt ◽

S. Broschart ◽

C.-D. Patz ◽

D. Rauhut ◽

M. Friedel ◽

...

Keyword(s):

Yeast Strain ◽

Wine Industry ◽

Sparkling Wine ◽

Alcohol Content ◽

Wine Production ◽

Alcohol Production ◽

Volatile Acidity ◽

Yeast Strains ◽

Lower Alcohol ◽

Commercial Yeast

Two commercial yeast strains with reduced alcohol production in comparison with a commercial yeast strain with common alcohol yield were assed for their suitability in sparkling wine production according to the traditional bottle fermentation. The different yeast strains were applied for the first fermentation. As expected the base wine differed in terms alcohol. Furthermore the yeast with lower alcohol content showed higher values of glycerol, higher arginine content and in the same time reduced levels of proline after fermentation. However those samples showed increased volatile acidity values, compared to the control wines. The later bottle fermentation with a uniform yeast strain showed similar fermentation kinetics for all four lots. Sensory evaluation showed no clear differences between the sparkling wines that were stored 9 months on the lees. The base wines nevertheless clearly differed from each other. Besides the increased production of volatile acidity, the tested yeast strains with lower alcohol production appear very promising for the sparkling wine industry to face the generally rising alcohol contents worldwide.

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Engineered Polyploid Yeast Strains Enable Efficient Xylose Utilization and Ethanol Production in Corn Hydrolysates

Frontiers in Bioengineering and Biotechnology ◽

10.3389/fbioe.2021.655272 ◽

2021 ◽

Vol 9 ◽

Author(s):

Lulu Liu ◽

Mingjie Jin ◽

Mingtao Huang ◽

Yixuan Zhu ◽

Wenjie Yuan ◽

...

Keyword(s):

Ethanol Production ◽

Comprehensive Evaluation ◽

Ethanol Yield ◽

Xylose Utilization ◽

Acid Pretreatment ◽

Experimental Conditions ◽

Total Sugars ◽

Yeast Strains ◽

Ethanol Yields ◽

Substrate Concentrations

The reported haploid Saccharomyces cerevisiae strain F106 can utilize xylose for ethanol production. After a series of XR and/or XDH mutations were introduced into F106, the XR-K270R mutant was found to outperform others. The corresponding haploid, diploid, and triploid strains were then constructed and their fermentation performance was compared. Strains F106-KR and the diploid produced an ethanol yield of 0.45 and 0.48 g/g total sugars, respectively, in simulated corn hydrolysates within 36 h. Using non-detoxicated corncob hydrolysate as the substrate, the ethanol yield with the triploid was approximately sevenfold than that of the diploid at 40°C. After a comprehensive evaluation of growth on corn stover hydrolysates pretreated with diluted acid or alkali and different substrate concentrations, ethanol yields of the triploid strain were consistently higher than those of the diploid using acid-pretreatment. These results demonstrate that the yeast chromosomal copy number is positively correlated with increased ethanol production under our experimental conditions.

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Yeast Cell Wall Chitin Reduces Wine Haze Formation

Applied and Environmental Microbiology ◽

10.1128/aem.00668-18 ◽

2018 ◽

Vol 84 (13) ◽

Cited By ~ 4

Author(s):

Thulile Ndlovu ◽

Benoit Divol ◽

Florian F. Bauer

Keyword(s):

Cell Wall ◽

Yeast Cell ◽

Wine Yeast ◽

Wine Industry ◽

Yeast Cell Wall ◽

Dependent Manner ◽

Concentration Dependent Manner ◽

Yeast Strains ◽

Protein Haze ◽

Haze Formation

ABSTRACT Protein haze formation in bottled wines is a significant concern for the global wine industry, and wine clarification before bottling is therefore a common but expensive practice. Previous studies have shown that wine yeast strains can reduce haze formation through the secretion of certain mannoproteins, but it has been suggested that other yeast-dependent haze protective mechanisms exist. On the other hand, the addition of chitin has been shown to reduce haze formation, likely because grape chitinases have been shown to be the major contributors to haze. In this study, Chardonnay grape must fermented by various yeast strains resulted in wines with different protein haze levels, indicating differences in haze-protective capacities of the strains. The cell wall chitin levels of these strains were determined, and a strong correlation between cell wall chitin levels and haze protection capability was observed. To further evaluate the mechanism of haze protection, Escherichia coli -produced green fluorescent protein (GFP)-tagged grape chitinase was shown to bind efficiently to yeast cell walls in a cell wall chitin concentration-dependent manner, while commercial chitinase was removed from synthetic wine in quantities that also correlated with the cell wall chitin levels of the strains. Our findings suggest a new mechanism of reducing wine haze, and we propose a strategy for optimizing wine yeast strains to improve wine clarification. IMPORTANCE In this study, we establish a new mechanism by which wine yeast strains can impact the protein haze formation of wines, and we demonstrate that yeast cell wall chitin binds grape chitinase in a chitin concentration-dependent manner. We also show that yeast can remove this haze-forming protein from wine. Chitin has in the past been shown to efficiently reduce wine haze formation when added to the wine in high concentration as a clarifying agent. Our data suggest that the selection of yeast strains with high levels of cell wall chitin can reduce protein haze. We also investigate how yeast cell wall chitin levels are affected by environmental conditions.

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Glycerol Overproduction by Engineered Saccharomyces cerevisiae Wine Yeast Strains Leads to Substantial Changes in By-Product Formation and to a Stimulation of Fermentation Rate in Stationary Phase

Applied and Environmental Microbiology ◽

10.1128/aem.65.1.143-149.1999 ◽

1999 ◽

Vol 65 (1) ◽

pp. 143-149 ◽

Cited By ~ 168

Author(s):

F. Remize ◽

J. L. Roustan ◽

J. M. Sablayrolles ◽

P. Barre ◽

S. Dequin

Keyword(s):

Stationary Phase ◽

Ethanol Yield ◽

Biomass Concentration ◽

Fold Increase ◽

Wine Yeast ◽

Product Formation ◽

Gene Encoding ◽

Haploid Strain ◽

Fermentation Rate ◽

Yeast Strains

ABSTRACT Six commercial wine yeast strains and three nonindustrial strains (two laboratory strains and one haploid strain derived from a wine yeast strain) were engineered to produce large amounts of glycerol with a lower ethanol yield. Overexpression of the GPD1 gene, encoding a glycerol-3-phosphate dehydrogenase, resulted in a 1.5- to 2.5-fold increase in glycerol production and a slight decrease in ethanol formation under conditions simulating wine fermentation. All the strains overexpressing GPD1 produced a larger amount of succinate and acetate, with marked differences in the level of these compounds between industrial and nonindustrial engineered strains. Acetoin and 2,3-butanediol formation was enhanced with significant variation between strains and in relation to the level of glycerol produced. Wine strains overproducing glycerol at moderate levels (12 to 18 g/liter) reduced acetoin almost completely to 2,3-butanediol. A lower biomass concentration was attained byGPD1-overexpressing strains, probably due to high acetaldehyde production during the growth phase. Despite the reduction in cell numbers, complete sugar exhaustion was achieved during fermentation in a sugar-rich medium. Surprisingly, the engineered wine yeast strains exhibited a significant increase in the fermentation rate in the stationary phase, which reduced the time of fermentation.

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An Overview of CRISPR-Based Technologies in Wine Yeasts to Improve Wine Flavor and Safety

Fermentation ◽

10.3390/fermentation7010005 ◽

2021 ◽

Vol 7 (1) ◽

pp. 5

Author(s):

Alice Vilela

Keyword(s):

Genetic Engineering ◽

Wine Yeast ◽

Wine Yeasts ◽

Wine Quality ◽

Yeast Strains ◽

Off Flavors ◽

Natural Isolates ◽

The Stability ◽

Wine Flavor ◽

New Yeast

Modern industrial winemaking is based on the use of specific starters of wine strains. Commercial wine strains present several advantages over natural isolates, and it is their use that guarantees the stability and reproducibility of industrial winemaking technologies. For the highly competitive wine market with new demands for improved wine quality and wine safety, it has become increasingly critical to develop new yeast strains. In the last decades, new possibilities arose for creating upgraded wine yeasts in the laboratory, resulting in the development of strains with better fermentation abilities, able to improve the sensory quality of wines and produce wines targeted to specific consumers, considering their health and nutrition requirements. However, only two genetically modified (GM) wine yeast strains are officially registered and approved for commercial use. Compared with traditional genetic engineering methods, CRISPR/Cas9 is described as efficient, versatile, cheap, easy-to-use, and able to target multiple sites. This genetic engineering technique has been applied to Saccharomyces cerevisiae since 2013. In this review, we aimed to overview the use of CRISPR/Cas9 editing technique in wine yeasts to combine develop phenotypes able to increase flavor compounds in wine without the development of off-flavors and aiding in the creation of “safer wines.”

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Selection and Adaptation of Saccharomyces cerevisae to Increased Ethanol Tolerance and Production

Polish Journal of Microbiology ◽

10.33073/pjm-2011-007 ◽

2011 ◽

Vol 60 (1) ◽

pp. 51-58 ◽

Cited By ~ 11

Author(s):

JAN FIEDUREK ◽

MARCIN SKOWRONEK ◽

ANNA GROMADA

Keyword(s):

Parent Strain ◽

Ethanol Concentration ◽

Ethanol Yield ◽

Sucrose Concentration ◽

Basal Medium ◽

Ethanol Stress ◽

Mineral Salts ◽

Yeast Strains ◽

Ethanol Yields ◽

Selection Of

A total of 24 yeast strains were tested for their capacity to produce ethanol, and of these, 8 were characterized by the best ethanol yields (73.11-8 1.78%). The most active mutant Saccharomyce s cerevisiae ER-A, resistant to ethanol stress, was characterized by high resistance to acidic (pH 1.0 and 2.0), oxidative (1 and 2% of H2O2), and high temperature (45 and 52 degrees C) stresses. During cultivation under all stress conditions, the mutants showed a considerably increased viability ranging widely from about 1.04 to 3.94-fold in comparison with the parent strain S. cerevisiae ER. At an initial sucrose concentration of 150 g/l in basal medium A containing yeast extract and mineral salts, at 300C and within 72 h, the most active strain, S. cerevisiae ER-A, reached an ethanol concentration of 80 g/1, ethanol productivity of 1.1 g/Il/h, and an ethanol yield (% of theoretical) of 99.13. Those values were significantly higher in comparison with parent strain (ethanol concentration 71 g/1 and productivity of 0,99 g/l/h). The present study seems to confirm the high effectiveness of selection of ethanol-resistant yeast strains by adaptation to high ethanol concentrations, for increased ethanol production.

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Reduction of Ethanol Yield and Improvement of Glycerol Formation by Adaptive Evolution of the Wine Yeast Saccharomyces cerevisiae under Hyperosmotic Conditions

Applied and Environmental Microbiology ◽

10.1128/aem.03710-13 ◽

2014 ◽

Vol 80 (8) ◽

pp. 2623-2632 ◽

Cited By ~ 89

Author(s):

Valentin Tilloy ◽

Anne Ortiz-Julien ◽

Sylvie Dequin

Keyword(s):

Saccharomyces Cerevisiae ◽

Adaptive Evolution ◽

Rational Design ◽

Ethanol Yield ◽

Wine Yeast ◽

Wine Industry ◽

Carbon Limitation ◽

Adaptive Laboratory Evolution ◽

Yeast Saccharomyces Cerevisiae ◽

Ancestral Strain

ABSTRACTThere is a strong demand from the wine industry for methodologies to reduce the alcohol content of wine without compromising wine's sensory characteristics. We assessed the potential of adaptive laboratory evolution strategies under hyperosmotic stress for generation ofSaccharomyces cerevisiaewine yeast strains with enhanced glycerol and reduced ethanol yields. Experimental evolution on KCl resulted, after 200 generations, in strains that had higher glycerol and lower ethanol production than the ancestral strain. This major metabolic shift was accompanied by reduced fermentative capacities, suggesting a trade-off between high glycerol production and fermentation rate. Several evolved strains retaining good fermentation performance were selected. These strains produced more succinate and 2,3-butanediol than the ancestral strain and did not accumulate undesirable organoleptic compounds, such as acetate, acetaldehyde, or acetoin. They survived better under osmotic stress and glucose starvation conditions than the ancestral strain, suggesting that the forces that drove the redirection of carbon fluxes involved a combination of osmotic and salt stresses and carbon limitation. To further decrease the ethanol yield, a breeding strategy was used, generating intrastrain hybrids that produced more glycerol than the evolved strain. Pilot-scale fermentation on Syrah using evolved and hybrid strains produced wine with 0.6% (vol/vol) and 1.3% (vol/vol) less ethanol, more glycerol and 2,3-butanediol, and less acetate than the ancestral strain. This work demonstrates that the combination of adaptive evolution and breeding is a valuable alternative to rational design for remodeling the yeast metabolic network.

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