Search results for "botany"
showing 10 items of 4586 documents
Wickerhamomyces sylviae f.a., sp. nov., an ascomycetous yeast species isolated from migratory birds.
2013
In the present work, we investigated the phylogenetic position and phenotypic characteristics of eight yeast isolates collected from migratory birds on the island of Ustica, Italy. A phylogenetic analysis based on the D1/D2 region of the large-subunit rRNA gene showed that all isolates clustered as a single separate lineage within the Wickerhamomyces clade. They exhibited distinct morphological and physiological characteristics and were clearly separated from their closest relatives, Wickerhamomyces lynferdii, Wickerhamomyces anomalus and Wickerhamomyces subpelliculosus, in blastn searches. On the basis of the isolation source, physiological features and molecular strain typing carried out …
Exploring the yeast biodiversity of green table olive industrial fermentations for technological applications
2011
In recent years, there has been an increasing interest in identifying and characterizing the yeast populations associated with diverse types of table olive elaborations because of the many desirable technological properties of these microorganisms. In this work, a total of 199 yeast isolates were directly obtained from industrial green table olive fermentations and genetically identified by means of a RFLP analysis of the 5.8S-ITS region and sequencing of the D1/D2 domains of the 26S rDNA gene. Candida diddensiae, Saccharomyces cerevisiae and Pichia membranifaciens were the most abundant yeast species isolated from directly brined Aloreña olives, while for Gordal and Manzanilla cultivars th…
Sampling procedure in a willow plantation for estimation of moisture content
2015
Abstract Heating value and fuel quality of wood is closely connected to moisture content. In this work the variation of moisture content (MC) of short rotation coppice (SRC) willow shoots is described for five clones during one harvesting season. Subsequently an appropriate sampling procedure minimising labour costs and sampling uncertainty is proposed, where the MC of a single stem section with the length of 10–50 cm corresponds to the mean shoot moisture content (MSMC) with a bias of maximum 11 g kg −1 . This bias can be reduced by selecting the stem section according to the particular clone. The average difference in MSMC between the largest and smallest shoot in a stump was 31 g kg −1 .…
Varietal and geographic classification of french red wines in terms of major acids
1989
Concentrations of acids other than malic and lactic appeared to be related more to area of production than to grape variety. These variables (2- hydroxyglutaric, butyric and isovaleric acid concentrations) were attributed to differences in the technological process used for vinification in the various areas. Shikimic and galacturonic acids were helpful for classifying and discriminating wine varieties. Principal component analysis characterised Cabernet Franc, Grenache and Carignan wines well by their acid content but failed to discriminate Merlot from Cabernet Sauvignon and Cinsault. Stepwise discriminant analysis allowed a clear separation of all wines according to the different varieties…
Analysis of non-Saccharomyces yeast populations isolated from grape musts from Sicily (Italy).
2008
Aims The aim of this study was to identify the non-Saccharomyces yeast populations present in the grape must microflora from wineries from different areas around the island of Sicily. Methods and results Yeasts identification was conducted on 2575 colonies isolated from six musts, characterized using Wallerstein Laboratory (WL) nutrient agar, restriction analysis of the amplified 5.8S-internal transcribed spacer region and restriction profiles of amplified 26S rDNA. In those colonies, we identified 11 different yeast species originating from wine musts from two different geographical areas of the island of Sicily. Conclusions We isolated non-Saccharomyces yeasts and described the microflora…
Fermentative stress adaptation of hybrids within the Saccharomyces sensu stricto complex.
2008
Along the fermentation process yeasts are affected by a succession of stress conditions that affect their viability and fermentation efficiency. Among the stress conditions the most relevant are high sugar concentration and low pH in musts, temperature and, as fermentation progresses, ethanol accumulation. Nowadays, due to the demanding nature of modern winemaking practices and sophisticated wine markets, there is an ever-growing search for particular wine yeast strains possessing a wide range of optimized, improved or novel enological characteristics. Traditionally, the species S. cerevisiae and S. bayanus within the Saccharomyces sensu stricto species are considered some of the most impor…
Selection and molecular characterization of wine yeasts isolated from the ‘El Penedès’ area (Spain)
2000
Abstract A study of the microbiota present during the wine fermentation of five grape varieties from the ‘El Penedes’ area (Spain) was carried out to select autochthonous yeast strains for industrial wine production. In this study we identified members of the genera Candida, Dekkera, Hanseniaspora, Kluyveromyces, Torulaspora, Zygosaccharomyces and Saccharomyces in wine fermentation microbiota. Strains of Saccharomyces cerevisiae, as responsible agents of the alcoholic fermentation, were considered for a selection protocol. In this work we applied different enological criteria for selection, but previously we have characterized and differentiated Saccharomyces isolates by molecular methods t…
Saccharomyces Yeasts I
2011
Publisher Summary This chapter discusses the microbiological aspects of saccharomyces yeasts in wine production. Yeasts, which play a central role in the winemaking process, are unicellular fungi that reproduce by budding. Most yeast belongs to the phylum Ascomycota on the basis of their sexual development. The selection of wine yeasts with specific genetic markers provides a system for the precise monitoring of the growth of particular strains during fermentation. Analyses of this type have shown that fermentation is driven mainly by inoculated yeasts, although these sometimes become only partially established. The growth of the natural flora is not completely suppressed during the initial…
Intraspecific biodiversity and 'spoilage potential' of Brettanomyces bruxellensis in Apulian wines
2015
Abstract The yeast Brettanomyces bruxellensis, generally considered the main oenological spoilage microbe, is able to survive during the winemaking process and it confers off-odors to wine, in reason of its ability to produce considerable amounts of volatile phenols. Forty-eight isolates of B. bruxellensis, obtained from several wines collected in Apulia (Southern Italy), were genetically characterized using an integrated approach, including a strain biodiversity analysis by Sau-PCR. Furthermore, the production of volatile phenols was assessed in wine and in synthetic medium, confirming the oenological spoilage potential of the analysed strains. Our findings indicate a remarkable genetic va…
Adaptive evolution of wine yeast.
2003
Abstract Alcoholic fermentation is one of the main phases in wine production. It is usually conducted by yeasts belonging to the species Saccharomyces cerevisiae. Industrial S. cerevisiae strains are highly specialized organisms, which have evolved to utilize to their full potential the different environments or ecological niches. So, during the alcoholic fermentation, the yeast has been adapted to different kinds of stress conditions; this adaptation is call “domestication”. In this review, we describe the different mechanisms involved in the adaptive evolution of wine yeast strains.