41. BIOTSKA RAZNOVRSTNOST KVASOVK POVEZANIH S PROIZVODNJO JABOLČNEGA VINAEivind Vangdal, Melita Sternad Lemut, Branka Mozetič Vodopivec, Lorena Butinar, 2017, published scientific conference contribution abstract Abstract: Na območju fjorda Hardanger, del zahodne Norveške, ima proizvodnja jabolčnega vina dolgo tradicijo in sicer sega v 12. stoletje, ko so menihi na tem območju začeli uvajati sadjarstvo. Danes je to glavno območje pridelovanja sadja na Norveškem. Kljub strogi regulativi proizvodnje alkoholnih pijač, pa se je na tem območju na nekaterih kmetijah ohranila tradicionalna proizvodnja jabolčnega vina. Namen naše študije je bil predvsem preučiti ekologijo in biotsko raznovrstnost kvasovk, ki so povezane s proizvodnjo tradicionalnega jabolčnega vina na območju Hardanger. Na tem območju smo tekom dveh zaporednih let vzorčili na 11-ih različnih lokacijah, kjer smo pri proizvajalcih vzorčili jabolčno vino, tla in različne dele jablan v sadovnjakih. Tako smo s pomočjo bogatitve v gojišču s povišanim sladkorjem in etanolom osamili približno 1300 izolatov kvasovk. Kvasovke smo s pomočjo multipleks PCR testa ločili na skupino kompleksa Saccharomyces sensu stricto in ne-Saccharomyces kvasovke. Nadalje smo izolate določili do nivoja vrste z izvedbo restrikcijske analize ITS PCR produktov, v nekaterih primerih smo za potrditev identifikacij opravili še določitev nukleotidnih zaporedij D1/D2 domene 26S rDNA. Kot pričakovano smo ugotovili, da sadovnjake naseljujejo predvsem ne-Saccharomyces kvasovke iz rodov Metschnikowia in Hanseniaspora, v tem okolju so bile Saccharomyces izolirane iz tal in jabolk. V jabolčnem vinu pa je bila pretežno izolirana vrsta S. uvarum, občasno pa tudi S. cerevisiae, Torulaspora delbrueckii in P. membranifacies.
Keywords: kvasovke, biotska raznovrstnost, jabolčno vino
Published in RUNG: 09.11.2017; Views: 5164; Downloads: 0
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42. Biodiversity of cider yeasts and their cider-making potentialEivind Vangdal, Melita Sternad Lemut, Branka Mozetič Vodopivec, Lorena Butinar, 2017, published scientific conference contribution abstract Abstract: In the area of Hardanger, a part of the fjord region in Western Norway, the production of apple wine (cider) has a long tradition that goes back to the 12th century, when monks introduced apple growing in this area. Nowadays, this is also the main area of fruit production in Norway. Despite the strict regulation of the alcoholic beverage production in Norway, traditional cider is still produced on some farms in this area. By tradition cider is produced by a spontaneous fermentation process of apple juice, performed by naturally occurring indigenous yeasts that originate from the fruit or the surfaces of the processing equipment. Therefore, our aim was primarily to study the ecology and biodiversity of the yeasts associated with the production of traditional cider in the Hardanger area. For two consecutive years, we sampled at 11 different locations in the observed region, where we collected cider samples and surface swabs of processing facilities from the cideries, and also soil and various parts of apple trees in orchards owned by the same producers. Thus, by enriching collected samples with the selective medium with high sugar and ethanol concentration, we managed to isolate about 1,300 yeasts. Based on the multiplex PCR results the yeasts were grouped into the Saccharomyces sensu stricto complex and non-Saccharomyces yeasts. The isolates were determined to the species level by performing the restriction analysis of ITS PCR products, and in some cases identifications were confirmed by sequencing of the D1/D2 domain of the 26S rDNA and/ or ITS region. As expected, non-Saccharomyces yeasts from the genus Metschnikowia and Hanseniaspora mainly populated the orchards, while the Saccharomyces yeasts were isolated in the orchards from the soil and fruits. In contrast, in ciders the species S. uvarum was predominantly found, occasionally also S. cerevisiae, Torulaspora delbrueckii and P. membranifacies. Indigenous cider yeasts were further on characterized in micro-plate format for the most important cider-making technological parameters (tolerance to ethanol, SO2, growth at low pH), for the presence of glucoside hydrolase activity, H2S production ability, and assimilation of malic acid. Based on this screenings the micro-scale fermentations of apple juice were performed with 13 different indigenous cider yeasts as monocultures. The most promising indigenous yeasts, T. delbrueckii and S. uvarum, were also tested as mixed cultures in sequential fermentations. Since the tested strain of T. delbrueckii as monoculture was not able to complete the alcoholic fermentation, better results were obtained in sequential fermentation with the mixed culture in combination with S. uvarum.
Keywords: indigenous yeasts, biodiversity, spontaneous fermentation, cider-making
Published in RUNG: 08.11.2017; Views: 6103; Downloads: 0
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43. Study of yeast biodiversity potential in the development of biological control agents against phytopathogenic fungi in viticultureMelita Sternad Lemut, Adesida Rowland, Urban Česnik, Lorena Butinar, 2017, published scientific conference contribution abstract Abstract: Despite public’s growing concerns for human health and environmental pollution, synthetic fungicides are still preferred and massively used for the protection of agricultural crop plants against fungal diseases. However, more and more research is focused on finding potential alternatives in the form of effective biological control agents. Although there are reports of yeast’s biocontrol activity, they are up to date poorly commercialized for such purposes.
As the yeasts represent an important part of the grape microflora, competing with other microorganisms (including pathogens) for nutrients and space, we decided to examine the potential of autochthonous yeasts as "green" alternatives in fighting against phytopathogens such as Botrytis cinerea in viticulture. With this aim we tested biocontrol activity of various strains / species of indigenous wine yeasts that were isolated from the vineyard environment in Slovenia and cross-border Italy. The yeasts were tested for the presence of siderophores, hydrolytic enzymes (chitinase, β-glucosidase and β-glucanase) and sensitivity to fungicides (copper, iprodion, cyprodinil + fludioxonil combination). The tests of phytopathogenic fungi growth inhibition in the presence of antagonistic yeast were also performed. The double Petri dish test was used to verify the inhibition of conidia germination by the formation of antifungal volatile organic compounds (VOC), synthetized by the antagonistic yeasts. The presence of hydrolytic enzymes was confirmed in many wine yeasts, particularly in the strains of Hanseniaspora uvarum and Metschnikowia pulcherrima species and in some strains of the Pichia genus. Using a medium, based on natural diluted grape juice in a double Petri dish test, we found that yeasts of the Debaryomyces hansenii, Lachancea thermotolerans, P. kudriavzevii, Saccharomyces kudriavzevii, S. cerevisiae and Torulaspora delbrueckii species were able to inhibit the germination of fungal conidia at the expense of the VOC formation. However, none of the up to date tested yeasts formed siderophores. On the other hand, the yeasts were generally resistant to the tested fungicide concentrations, thus they could be used as potential biofungicides in the combination with chemical fungicides.
Keywords: yeasts, biocontrol, Botrytis cinerea, viticulture
Published in RUNG: 08.11.2017; Views: 4511; Downloads: 0
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44. Preučevanje potenciala biotske raznovrstnosti kvasovk za razvoj alternativnih biofungicidov v vinogradništvuMelita Sternad Lemut, Adesida Rowland, Ajda Lemut, Urban Česnik, Lorena Butinar, 2017, published scientific conference contribution abstract Keywords: biotska raznovrstnost, kvasovke, biokontrolna aktivnost, biofungicid, Botrytis cinerea, trajnostno vinogradništvo
Published in RUNG: 28.09.2017; Views: 5010; Downloads: 0
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45. Study of grapevine early leaf removal sustainability potential by means of targeted metabolomic approachMelita Sternad Lemut, Paolo Sivilotti, Lorena Butinar, Ajda Lemut, Urška Vrhovšek, 2017, published scientific conference contribution abstract Keywords: Pinot gris, early leaf removal, sustainable viticulture, grape compactness, targeted metabolomics, phenolic compounds
Published in RUNG: 21.09.2017; Views: 5111; Downloads: 0
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46. Combined effects of early season leaf removal and climatic conditions on aroma precursors in ‘Sauvignon blanc’ grapesPaolo Sivilotti, Rachele FALCHI, Jose Carlos Herrera, Branka Škvarč, Lorena Butinar, Melita Sternad Lemut, Marijan Bubola, Paolo SABBATINI, Klemen Lisjak, Andreja Vanzo, 2017, original scientific article Abstract: Early leaf removal around the cluster zone is a common technique applied in cool climate viticulture, to regulate yield components and improve fruit quality. Despite the increasing amount of information on early leaf removal and its impact on total soluble solids, anthocyanins and polyphenols, less is known regarding aroma compounds. In order to verify the hypothesis that defoliation, applied before or after flowering, could impact the biosynthesis of thiol precursors, we performed a two year (2013 and 2014) experiment on Sauvignon blanc. We provided evidence that differential accumulation of thiols precursors in berries is affected by the timing of defoliation and this impact was related to modifications in biosynthetic pathway. Furthermore, the possible interaction between leaf removal treatment and seasonal weather conditions, and its effect on the biosynthesis of volatile precursors are discussed. Our results suggested that in Sauvignon blanc the relative proportion of 4-S-glutathionyl-4-methylpentan-2-one (G-4MSP) and 3-S-glutathionylhexan-1-ol (G-3SH) precursors can be affected by defoliation, and this could be related to the induction of two specific genes encoding glutathione-S-transferases (VvGST3 and VvGST5), while no significant effects on basic fruit chemical parameters, polyphenols and methoxypyrazines were ascertained under our experimental conditions.
Keywords: early leaf removal, cluster exposure, thiol precursors, methoxypyrazines, glutathione S-transferase, Vitis vinifera
Published in RUNG: 31.08.2017; Views: 4299; Downloads: 0
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48. Isolation and selection wild yeasts for winemakingNatalia Mikhaylina, 2017, undergraduate thesis Abstract: The aim of this study was to explore the diversity of fermentative yeast species in a non-vineyard and vineyard environment, and exploit their oenological potential. For this purpose we collected plant and soil material in the vineyard (located in Črniče in Vipava Valley) planted with Vitis vinifera L. and in the forest (forest in Vipava Old Castle), and by using a selective medium with high ethanol and sugar content we managed to obtain 35 isolates. By sequencing the D1/D2 domain of the 26S rDNA we identified nine different yeast species. The oenological potential of identified yeasts was further investigated by employing a series of tests, such as growth at low pH values, tolerance to ethanol and sulfur, and H2S production ability. Based on the results of these tests we selected four different yeast species for the microvinification of Vitis vinifera L. cv. ‘Pinot Noir’ grape juice. A commercial strain Saccharomyces cerevisiae Lalvin D47 was also included as a control in the fermentation experiment. Fermentation monitoring was done by measuring daily weight loss and microbiological analysis in the middle of fermentation. For the final wines, sugars were determined and sensorial evaluation performed. Among four tested yeasts, S. paradoxus IVV 32 and Torulaspora delbrueckii IVV 36 appeared to be the most promising for winemaking, but further studies should be carried out.
Keywords: wine, Vitis vinifera L. cv. ‘Pinot Noir’, biodiversity, yeasts, fermentation
Published in RUNG: 10.07.2017; Views: 5834; Downloads: 283
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49. Alternativne vinogradniške in vinarske tehnologije: kakovostni, trajnostni in senzorični potencial : /Melita Sternad Lemut, Paolo Sivilotti, Lorena Butinar, Jana Laganis, Urška Vrhovšek, 2017, published scientific conference contribution abstract (invited lecture) Keywords: odstajevanju listov v predelu grozdov, trajnostno vinogradništvo, Botrytis cinerea, mikrobna ekologija vinske trte, alternativne vinarske tehnologije, senzorika vina.
Published in RUNG: 29.06.2017; Views: 5043; Downloads: 252
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