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Survey of Hydrogen Sulphide Production by Wine Yeasts
Abstract
Twenty-one strains of commercial wine yeasts and 17 non-Saccharomyces species of different provenance were surveyed for their ability to produce hydrogen sulphide in synthetic grape juice medium indicator agar with different nitrogen sources, as well as in natural grape juice. Bacto Biggy agar, a commercially available bismuth-containing agar, was used to compare our results with others previously reported in the literature. Under identical physiological conditions, the strains used in this study displayed similar growth patterns but varied in colony color intensity in all media, suggesting significant differences in sulphite reductase activity. Sulphite reductase activity was absent for only one strain of Saccharomyces cerevisiae. All other strains produced an off-odor to different extents, depending significantly (P <0.05) on medium composition. Within the same species of some non-Saccharomyces yeasts, strain variation existed as it did for Saccharomyces. In natural musts, strains fell into three major groups: (i) nonproducers, (ii) must-composition-dependent producers, and (iii) invariable producers. In synthetic media, the formation of sulphide by strains of S. cerevisiae results from the reduction of sulphate. Therefore, this rapid screening methodology promises to be a very useful tool for winemakers for determining the risk of hydrogen sulphide formation by a given yeast strain in a specific grape juice.
... The yeast strains were spot-inoculated and incubated at 25 ± 1 • C for 48 h. H 2 S production was evaluated using an arbitrary scale from 1 (white color = no production) to 5 (dark brown = high production) [18]. Commercial yeast strain Vin 13 (Anchor Oenology ® , Cape Town, South Africa) was used as control. ...
... In the ethanol tolerance assay (14% v/v), it was observed that 50% of the Viognier yeast isolates started fermenting after 24 h, while Chardonnay grape must strains demonstrated [18], yeast strains in the present study exhibited low or medium (corresponding to levels 2 and 3 of the proposed scale) potential for H 2 S production, with low values of 84.61% and 83.33% for Viognier and Chardonnay, respectively. ...
... Evaluation of growth capacity at low temperature (15 °C) demonstrated that 30.77% of the Viognier isolates and 41.67% of the Chardonnay isolates began fermentation after 48 h. Finally, the H2S production assay revealed that, according to the scale proposed by [18], yeast strains in the present study exhibited low or medium (corresponding to levels 2 and 3 of the proposed scale) potential for H2S production, with low values of 84.61% and 83.33% for Viognier and Chardonnay, respectively. ...
Yeasts play a crucial role in the winemaking process contributing to the typicity and originality of wines in a region. Therefore, the aim of the present study was to isolate, characterize, and select yeasts from the Geographical Indication “Pozo de Los Algarrobos”, San Juan, Argentina. Yeasts were directly isolated from grapes and at different stages of spontaneous fermentations of Vitis vinifera Viognier and Chardonnay varieties. Molecular and intraspecific identification of Saccharomyces cerevisiae yeasts was conducted using the D1/D2 domain and interdelta, respectively, observing 13 different yeast strains from Viognier and 12 from Chardonnay vinifications. Based on the enological traits assayed, two strains, V22 (Viognier) and C14 (Chardonnay), were selected for further studies. Microvinifications with these yeasts were carried out with Viognier and Chardonnay grape must in 2 L flasks, and the resulting wines were analytically and sensorially evaluated. Overall, strain V22 produced wines with positive and particular sensory properties, associated with fruity and floral aromas, color intensity, sweetness, aromatic persistence, and varietal typicity. Consequently, biomass propagation of V22 was conducted to inoculate pilot- (100 L) and industrial (12,000 L)-scale fermentations. V22 resulted in a correct wine fermentation performance obtaining a final product with distinctive and genuine properties.
... The wine fermentation process is supported by wine yeast and involves changes in the composition of sulfur compounds that are connected with the biosynthesis of Scontaining amino acids cysteine and methionine through the sulfate assimilatory reduction pathway [16,18,[30][31][32][33]. ...
... According to several studies [32,36], the lack of nitrogenous substances in the must is considered the main reason for hydrogen sulfide formation. On the other hand, some experiments proved that H 2 S is also formed in conditions where assimilable nitrogen is present or supplemented [12,32,36]. ...
... According to several studies [32,36], the lack of nitrogenous substances in the must is considered the main reason for hydrogen sulfide formation. On the other hand, some experiments proved that H 2 S is also formed in conditions where assimilable nitrogen is present or supplemented [12,32,36]. Ugliano et al. [12] stated that nitrogen supplementation in wine to influence the formation of H 2 S stem is from the initial yeast assimilable nitrogen and yeast properties that produce H 2 S. The explanation of the excessive formation of H 2 S is based on the permanent exposition of vineyards to stress conditions (drought, malnutrition, overload). ...
The review summarizes the latest scientific findings and recommendations for the prevention of three very common wine faults of non-microbial origin. The first group, presented by the reductive aromas, is caused mainly by excessive H2S and other volatile sulfur compounds with a negative impact on wine quality. The most efficient prevention of undesirable reductive aromas in wine lies in creating optimal conditions for yeast and controlling the chemistry of sulfur compounds, and the pros and cons of correction methods are discussed. The second is browning which is associated especially with the enzymatic and non-enzymatic reaction of polyphenols and the prevention of this fault is connected with decreasing the polyphenol content in must, lowering oxygen access during handling, the use of antioxidants, and correction stands for the use of fining agents. The third fault, atypical aging, mostly occurs in the agrotechnics of the entire green land cover in the vineyard and the associated stress from lack of nutrients and moisture. Typical fox tones, naphthalene, or wet towel off-odors, especially in white wines are possible to prevent by proper moisture and grassland cover and alternating greenery combined with harmonious nutrition, while the correction is possible only partially with an application of fresh yeast. With the current knowledge, the mistakes in wines of non-microbial origin can be reliably prevented. Prevention is essential because corrective solutions for the faults are difficult and never perfect.
... thermotolerans, and M. pulcherrima, were observed for H2S production under the same condition [4,7,56]. ...
... On the other hand, however, contributions of other fermentation-related factors are also nonnegligible, among which, nitrogen has long been the top research interest. As a pilot study, Mendes-Ferreira and colleagues recorded no significant differences for the production of H2S under certain nitrogen sources (amino acids, DAP, and (NH4)2SO4) for several non-Saccharomyces strains, while cysteine was provided as the sole nitrogen source supported the highest sulphide production, as agreed with S. cerevisiae [56]. A few studies were conducted to investigate nitrogen influence on the production of other sulfur-containing volatile compounds ( Table 4). ...
... Non-producers remain white. Different rankings (0-4) were given according to the coloration of the colonies: 0, white; 1, light brown; 2, brown; 3, dark brown and 4, black [34]. ...
The growing customer demand for diversified brewery products is pushing the brewery industry to search for brewer’s yeasts. The aim of this study was to screen and evaluate the brewing potential of eight S. cerevisiae strains isolated from Ethiopian traditional fermented beverages. They were screened for potential brewer’s yeast characteristics, and then their brewing performance were evaluated on a laboratory scale. Screening data indicated that all strains demonstrated reasonable brewing characteristics. Brewing performances evaluation has shown that tested strains showed reasonable performance. They yield ethanol content ranging between 5.2 ± 0.2 and 5.5 ± 0.2 (v/v%) with degree of attenuation varying between 64.1 ± 6.8 and 72.6 ± 2.0%. Compared to the investigated strains, the commercial strain showed remarkable performance with ethanol production (6.1 ± 0.2, v/v%) and attenuation degree (82.2 ± 2.0%). Produced beers were analyzed for sensorial attributes, and they were not statistically significant in all tested sensorial profiles, except beers produced by MABD1 and Sc. JD9, which were recognized as extremely bitter by two tasters. FT-IR spectra matching of experimental and reference beers revealed that beer samples exhibited the same spectral pattern, implying they have a similar chemical profile. Studies focused on the understanding of the determinant abiotic factors for an acceptable performance of the investigated S. cerevisiae strains at the simulated industrial-scale brewing condition is recommended. Moreover, adaptation to maltose and malto-dextrin assimilation at low temperature condition is recommended.
... Yeast strains vary greatly in their production of H 2 S with some yeasts, such as S. cerevisiae UCD522 (Montrachet), that are reported as high producers of H 2 S [9,10] whereas other strains such as EC1118 are noted as low producers [11]. Recently, strains have been developed that purportedly produce no H 2 S due to allele differences in the MET10 gene which encodes for catalytic subunits in sulfite reductase, a key enzyme in the SRS [9]. ...
The influence of yeast assimilable nitrogen (YAN) and elemental sulfur (S0) on the formation of volatile sulfur compounds (VSCs) during fermentation was investigated. Pinot noir fermentations were performed using Saccharomyces cerevisiae strain UCD522 or P1Y2 with an addition of 0, 5, or 15 µg/g elemental sulfur. H2S production during fermentation was measured using lead acetate tubes and additional VSCs measured by GC-PFPD. The addition of S0 resulted in H2S formation during alcoholic fermentation regardless of which yeast strain was used. H2S production was greater in fermentations performed by UCD522 with increasing amounts of S0 resulting in increased production of H2S. Higher S0 resulted in wines containing higher concentrations of methyl thioacetate and glutathione disulfide. Additional experiments examined the impact of nitrogen composition and S0. The addition of diammonium phosphate (DAP) resulted in an increase in H2S formation during fermentation whereas the addition of amino acids did not, whether S0 was added or not. Fermentations where DAP and S0 were both added produced a higher concentration of H2S compared to fermentations where S0 or DAP additions were made individually. VSCs in the wine were also impacted by the addition of nitrogen and/or S0 with the addition of S0 and nitrogen (DAP or amino acids) resulting in elevated concentrations of methyl thioacetate in the wines.
... [31] These characteristics were used in this study to exclude yeasts that did not show the ability to ferment sugars present in the wort, such as glucose, sucrose, and maltose, and yeasts with a medium or high production of hydrogen sulfide. Marongiu et al. [32] obtained 9 out of 12 isolates able to ferment maltose from sourdough and Hayford and Jespersen [33] reported 47 out of 48 from fermented maize dough, while our tests demonstrated that only 12 out of 92 isolates were able to ferment glucose, sucrose, and maltose, probably because fruits are not a source of maltose and maltose fermentation is species or yeast strain dependent. [8] Brewer's yeasts can produce around 500 different aromas and aromatic compounds. ...
Ninety-two wild yeasts were isolated from different fruits, for possible use in brewing, using the technological traits of carbohydrate fermentation and hydrogen sulfide production. Twelve yeasts were selected for identification by sequencing (D1/D2 domain or ITS1-5.8S-ITS2 region) and their volatile compounds production analyzed using gas chromatography. From these analyses, three yeasts were chosen for further characterization and beer production. Strains were characterized by their tolerance to osmotic and ethanol stress, their flocculation profile, growth at different temperatures, apparent attenuation (percentage of sugars converted into alcohol), estimated ABV (alcohol by volume) and reducing sugar profile. Beers were analyzed for alcohol content and sensorial analysis. The isolates CL011 and PB111 (Saccharomyces cerevisiae) and CB341 (Wickerhamomyces anomalus) showed promising properties for brewing, which included high production of interesting volatile compounds (esters, terpenes, lactones, and C13-norisoprenoids) by CL011, a neutral profile by PB111, and the production of non-classic beer volatile compounds by CB341 in a mixed culture.
Supplemental data for this article is available online at https://doi.org/10.1080/03610470.2022.2031777 .
... During wine fermentation, the assimilatory reduction of sulphate by wine yeast (to biosynthesise cysteine and methionine) can lead to the excessive production of the HS − ion, which leads to the formation of H 2 S in wine [25,[86][87][88]. This is probably one of the most common problems in a winery, and if not treated, the resulting wine will be tainted leading to a loss in quality and the possibility of rejection by consumers. ...
A wine’s aroma profile is an important part of the criteria affecting wine acceptability by consumers. Its characterisation is complex because volatile molecules usually belong to different classes such as alcohols, esters, aldehydes, acids, terpenes, phenols and lactones with a wide range of polarity, concentrations and undesirable off-aromas. This review focused on mechanisms and conditions of the formation of individual aroma compounds in wine such as esters and higher alcohols by yeast during fermentation. Additionally, aroma losses during fermentation are currently the subject of many studies because they can lead to a reduction in wine quality. Principles of aroma losses, their prevention and recovery techniques are described in this review.
... To assess hydrogen sulphide production, 10 µL of each strain from the previously prepared YPD liquid were inoculated on the BIGGY medium and kept for 2-3 days at 24 • C, respectively. Visual scale was used as a function of the increasing level of H 2 S produced [10,29,36,37]. ...
Yeasts undergo intensive metabolic changes during the early stages of fermentation. Previous reports suggest the early production of hydrogen sulfide (H2S) is associated with the release of a range of volatile sulfur compounds (VSCs), as well as the production of varietal thiol compounds 3-sulfanylhexan-1-ol (3SH) and 3-sulfanylhexyl acetate (3SHA) from six-carbon precursors including (E)-hex-2-enal. In this study, we investigated the early H2S potential, VSCs/thiol output, and precursor metabolism of 11 commonly used laboratory and commercial Saccharomyces cerevisiae strains in chemically defined synthetic grape medium (SGM) within 12 hours after inoculation. Considerable variability in early H2S potential was observed among the strains surveyed. Chemical profiling suggested that early H2S production correlates with the production of dimethyl disulfide, 2-mercaptoethanol, and diethyl sulfide, but not with 3SH or 3SHA. All strains were capable of metabolizing (E)-hex-2-enal while the F15 strain showed significantly higher residue at 12 h. Early production of 3SH, but not 3SHA, can be detected in the presence of exogenous (E)-hex-2-enal and H2S. Therefore, the natural variability of early yeast H2S production contributes to the early output of selected VSCs, but the threshold of which is likely not high enough to contribute substantially to free varietal thiols in SGM.
Yeast is a leavening agent used to aid the fermentation process in bread making, by producing ethanol, as well as carbon dioxide, to improve the aroma, and increase the dough's volume, respectively. In Indonesia, the yeast used in bread making is imported. Thus, there is a need for homegrown alternatives. This study, therefore, aims to obtain yeast isolates with the capacity to act as bread leavening agents from the skin and flesh of Mangifera indica var. Podang. In this study, a total of three endophytic isolates, YDM-1, and YDM-3, from the fruit's flesh, as well as YKM-1 from the skin, were obtained. YDM-1 and YKM-1 were identified macroscopically and microscopically as Ascomycota class and Hemiascomycetes sub-class. In comparison, YDM-3 was identified as Ascomycota class and Archiascomycetes sub-class. Subsequently, the isolates were subjected to carbohydrate fermentation, 50% glucose tolerance, flocculation, hydrogen sulfide compound, temperature tolerance, and ethanol tolerance analyses. The three isolates have met the criteria for leavening yeast. YDM-3 and YKM-1 are able to produce a similar increase in the volume of bread dough commercial yeast, with an incubation period of 12 hours. Meanwhile, YKM-1 produced the best aroma as well as the best potential in developing bread and is, therefore, suitable to be used as commercial yeast.
Five indicators of vine nitrogen status were compared for their accuracy to differentiate two levels of nitrogen fertilization (0 and 45 kg N/ha): petiole total nitrogen content, leaf blade color intensity measured by a device called "N-tester", grape juice total nitrogen content, grape juice assimilable nitrogen content and grape juice ammonium content. Differences in must total nitrogen content and must assimilable nitrogen content were highly significant between fertilization levels. They can be considered as two powerful tools to assess vine nitrogen status. Levels of must total nitrogen content and must assimilable nitrogen content were highly correlated. Mineralizing must in order to measure its total nitrogen content is difficult, mainly because of the presence of large amounts of sugar. This operation can take more than 12 hours and it can fail because of caramelization and the appearance of foam. We propose mineralizing must by means of microwave. Complete mineralization was obtained in only one hour. No foam or caramelization was observed on any of the samples mineralized. Vine nitrogen uptake is likely to vary to a considerable extend with soil parameters, even if no nitrogen fertilization is applied. Figuring among those parameters are: soil organic matter content, organic matter C/N ratio and soil organic matter turnover. The latter depends mainly on soil temperature, soil aeration, soil pH and soil moisture content. Differences in vine nitrogen status depending on the soil type were clearly evidenced by measuring must total nitrogen and must assimilable nitrogen at ripeness. Limited nitrogen uptake, as a result of particular soil conditions, can limit vine vigor and be a quality enhancing factor in red grape production. This emphasizes the role of moderate environmental stress in the production of high quality potential grapes.
Volatile sulfur compounds (VSCs) and nonvolatile thiol-containing compounds (NVTCs), which are potential precursors of VSCs, were monitored by gas chromatography during fermentation of eight white grape musts: one Thompson Seedless, one Palomino, one Chenin blanc, two Sauvignon blancs, and three Chardonnays. The assimilable amino acid (EAA) concentration of the musts ranged from 480 mg/L to 2022 mg/L (mean = 1131 mg/L). Using a GC-flame photometric detector, three sulfur containing peaks were tentatively identified based on their retention times: hydrogen sulfide (H2S), ethylmercaptan, dimethylsulfide, and one unknown peak (RT, 9.7 min) was detected. The predominant VSC, H2S, was continuously produced throughout fermentation and was highest during rapid growth phase of yeast. All juices produced H2S most rapidly during rapid yeast growth, but musts with low EAA generally produced higher levels of H2S throughout the fermentation. Total H2S, which ranged from 112 to 516 mg/L, was inversely correlated with concentration of assimilable amino acids (p < 0.01) and with total nitrogen content (p < 0.10). H2S at the end of fermentation was negatively correlated with EAA (p < 0.01) and positively with days to dryness (p < 0.05). For all musts, concentration of NVTCs, primarily glutathione (GSH), steadily increased towards the end of fermentation. Final wine concentration of GSH (0.1 to 5.1 mg/L) was correlated with both total N (p < 0.01) and EAA (p < 0.05).
Hydrogen sulfide production was investigated in 29 strains of Saccharomyces cerevisiae - two commercial and 27 natural isolates. Sulfide formation was evaluated under two synthetic juice conditions: one leading to full expression of the sulfate reduction sequence and the other to maximal repression of this pathway. Strains could be categorized as high, medium, low, or non-producers under each of these conditions. There was no correlation between category of production in these two media for the strains evaluated, but for each strain, production under repressing conditions was much less. Under repressing conditions, H2S production decreased from 4- to 560-fold depending upon the strain, with the majority of strains displaying a 200-fold or greater reduction in production. Hydrogen sulfide formation was also evaluated in natural and synthetic juices that establish conditions intermediate between full repression and induction of the sulfate reduction sequence, and with sulfur dioxide or with limitation for other components. Yeast variability in H2S formation was greatest under conditions of marginal nitrogen content of the medium, but there was not a simple correlation of amount of H2S formed and total nitrogen content, fermentation rate, or time of formation during fermentation. The effectiveness of nitrogen (diammonium phosphate) addition in commercial isolate UCD522 was found to be dependent upon the concentration of methionine in the medium. The effectiveness of methionine addition at suppression of hydrogen sulfide formation was similarly dependent upon the ammonium (or total nitrogen) content. At low methionine concentrations, DAP impact on H2S was minimal, and at low ammonium concentrations the effect of methionine addition was likewise minimal. Genetic analysis of one strain revealed that hydrogen sulfide formation is under the control of several genes, consistent with what is known about the complex regulation of the sulfate reduction pathway.
