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1.
Changes in the relative abundance of two Saccharomyces species from oak forests to wine fermentations
Jure Piškur, Justin C. Fay, Lorena Butinar, Sofia Dashko, Helena Volk, Ping Liu, 2016, original scientific article

Abstract: Saccharomyces cerevisiae and its sibling species S. paradoxus are known to inhabit temperate arboreal habitats across the globe. Despite their sympatric distribution in the wild, S. cerevisiae is predominantly associated with human fermentations. The apparent ecological differentiation of these species is particularly striking in Europe where S. paradoxus is abundant in forests and S. cerevisiae is abundant in vineyards. However, ecological differences may be confounded with geographic differences in species abundance. To compare the distribution and abundance of these two species we isolated Saccharomyces strains from over 1,200 samples taken from vineyard and forest habitats in Slovenia. We isolated numerous strains of S. cerevisiae and S. paradoxus as well as small number of S. kudriavzevii strains from both vineyard and forest environments. We find S. cerevisiae less abundant than S. paradoxus on oak trees both within and outside the vineyard, but more abundant on grapevines and associated substrates. Analysis of the uncultured microbiome shows that both S. cerevisiae and S. paradoxus are rare species in soil and bark samples, but can be much more common in grape must. In contrast to S. paradoxus, European strains of S. cerevisiae have acquired multiple traits thought to be important for life in the vineyard and dominance of wine fermentations. We conclude that S. cerevisiae and S. paradoxus currently share both vineyard and non-vineyard habitats in Slovenia and we discuss factors relevant to their global distribution and relative abundance.
Found in: ključnih besedah
Summary of found: ...Wine, microbiome, yeast, Ecology, Fermentation...
Keywords: Wine, microbiome, yeast, Ecology, Fermentation
Published: 12.02.2016; Views: 1971; Downloads: 103
.pdf Fulltext (3,21 MB)

2.
Biogas production from brewery yeast in an EGSB reactor
Romana Marinšek-Logar, Matej Oset, Miran Klemenčič, Milenko Roš, Gregor Drago Zupančič, 2016, professional article

Abstract: Experience over a five-year period of full throughput using anaerobic co-digestion of brewery yeast for biogas production is described in this contribution. The brewery, with a total amount of available yeast (0.7 v/v %), had a 26.2 % increase in COD load and a 38.5 % increase in biogas production resulting in an increase in the biomethane/natural gas substitution ratio in the brewery from 10 % to 16 %.
Found in: ključnih besedah
Keywords: Anaerobic digestion, biogas production, brewery yeast, brewery wastewater, EGSB
Published: 21.04.2016; Views: 2279; Downloads: 0
.pdf Fulltext (267,88 KB)

3.
Introduction to carbon metabolism in yeast
Jure Piškur, Sofia Dashko, Concetta Compagno, 2014, independent scientific component part or a chapter in a monograph

Found in: ključnih besedah
Keywords: yeast, carbon metabolism, alcohilic fermentation
Published: 09.05.2017; Views: 1267; Downloads: 8
URL Fulltext (0,00 KB)

4.
Biogas Production from Brewer’s Yeast Using an Anaerobic Sequencing Batch Reactor
Gregor Drago Zupančič, Mario Panjicko, Bruno Zelić, 2017, original scientific article

Abstract: Renewable energy sources are becoming increasingly important in the beverage and food industries. In the brewing industry, a significant percentage of the used raw materials finishes the process as secondary resource or waste. The research on the anaerobic digestion of brewer’s yeast has been scarce until recent years. One of the reasons for this is its use as a secondary resource in the food industry and as cattle feed. Additionally, market value of brewer’s yeast is higher than its energy value. Due to the increase of energy prices, brewer’s yeast has become of interest as energy substrate despite its difficult degradability in anaerobic conditions. The anaerobic co-digestion of brewer’s yeast and anaerobically treated brewery wastewater was studied using a pilot-scale anaerobic sequencing batch reactor (ASBR) seeded with granular biomass. The experiments showed very good and stable operation with an organic loading rate of up to 8.0 kg/(m3·day), and with a maximum achieved organic loading rate of 13.6 kg/(m3·day) in a single cycle. A specific biogas productivity of over 0.430 m3/kg of the total chemical oxygen demand (COD) inserted, and total COD removal efficiencies of over 90 % were achieved. This study suggests that the brewer’s yeast can be successfully digested in an ASBR without adverse effects on the biogas production from brewer's yeast/wastewater mixtures of up to 8 % (by volume). By using the brewer's yeast in the ASBR process, the biogas production from brewery wastewater could be increased by 50 %.
Found in: ključnih besedah
Keywords: anaerobic digestion, ASBR, biogas, brewer’s yeast
Published: 15.06.2017; Views: 1373; Downloads: 0
.pdf Fulltext (728,20 KB)

5.
Simple and fast HPLC-DAD method for determination of HCDC activity and formation of vinylphenol in Saccharomyces and non-Saccharomyces yeast
Jelena Topič, Lorena Butinar, Dorota Korte, Branka Mozetič Vodopivec, published scientific conference contribution abstract

Abstract: Conventionally, alcoholic fermentation in the production of wine is performed by yeast species Saccharomyces cerevisiae. There are numerous starters available, however due to the growing demand for wines with specific characteristics, other Saccharomyces and non-Saccharomyces species are being investigated for potential use as starters. [1]. Yeast selection has involved the development of techniques for detecting strains that might improve wines in terms of aroma, structure, colour and other technological properties [2]. Colour of the wine can be affected as some metabolites produced by yeast during fermentation may react with grape anthocyanins to produce highly stable pyranoanthocyanins. For the facilitation of formation of vinylphenolic pyranoanthocyanins, yeast strains with high hydroxycinnamate decarboxylase activity are used (HCDC). The mechanism of reaction is decarboxylation of hydroxycinnamic acids and formation of vinylphenols that condense with grape anthocyanins and form stabile vinyphenolic pyranoanthocyanin adducts [3]. It has been demonstrated that some non-Saccharomyces strains (Pichia guillermondii, Schizosaccharomyces pombe) have positive HCDC activity and they can produce vinylphenolic pyranoanthocyanins in higher concentrations than S. cerevisiae. A simple way of determining whether the yeast strain has HCDC activity or not, is the use of fermentation media with the addition of hydroxycinnamic acids, such as p-coumaric acid. The degradation of p-coumaric acid and transformation into 4-vinylphenol (and possibly in 4-ethylphenol) can be checked by LC-DAD. Most of the published data has been done on smaller number of strains. The goal of our work was to develop simple method for the screening of Slovenian in-house yeast collection, comprising of native isolates that mostly originated from Vipava valley and Karst region, and therefore try to determine strains with high HCDC activity. These strains can be used for wine fermentations in order to produce more stable pyranoanthocyanins; which is especially important in wines that has less anthocyanin concentration already from the grape, such as Pinot Noir. 103 different yeast strains belonging to 28 species were selected for the assessment of HCDC activity. In some cases the difference in p-coumaric acid metabolism rate between two strains exceeded 90%. All tested S. paradoxus strains showed higher than 40% degradation rate of p-coumaric acid. HCDC activity of S. cerevisiae strains which is the species most commonly used in fermentation, varied between 5.1 and 66.1%. The commercial strains tested, FPC and EC118 showed 43.9 and 21.5% conversion rate, respectively. It was observed that some native strains had higher HCDC activity than commercial tested ones. Three strains produced vinylphenol in concentration higher than 50 ppm, two of them being P. guillermondii and another strain being S. paradoxus (Sut85). In general strain with high HCDC activity also produced high concentration of 4-vinylphenol. The results showed that HCDC activity is highly strain dependent, which correlates with the literature data available. The proposed method is very simple and does not require special sample preparation prior to HPLC analysis. Furthermore, the proposed fermentations in deep-well microtiter plates allow the screening of high number of strains. The method could be used for routine screening, to determine which strain has high HCDC activity and produces high concentration of vinylphenols and can therefore be used in future for determination of strains ability to synthesize vinylphenolic pyranoanthocyanins.
Found in: ključnih besedah
Keywords: yeast, hydroxycinnamate decarboxylase, 4-vinylphenol
Published: 18.06.2018; Views: 1071; Downloads: 0
.pdf Fulltext (4,46 MB)

6.
7.
Modulation of Pinot Noir wine colour by yeast selection
Dorota Korte, Lorena Butinar, Jelena Topić Božič, Branka Mozetič Vodopivec, 2019, published scientific conference contribution abstract

Found in: ključnih besedah
Keywords: yeast, HCDC activity, wine colour, Pinot Noir, pyranoanthocyanins
Published: 27.05.2019; Views: 327; Downloads: 0
.pdf Fulltext (157,36 KB)

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