Ilaria Mannazzu

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Mixed fermentations using controlled inoculation of Saccharomyces cerevisiae starter cultures and non-Saccharomyces yeasts represent a feasible way towards improving the complexity and enhancing the particular and specific characteristics of wines. The profusion of selected starter cultures has allowed the more widespread use of inoculated fermentations,(More)
Non-Saccharomyces yeasts are metabolically active during spontaneous and inoculated must fermentations, and by producing a plethora of by-products, they can contribute to the definition of the wine aroma. Thus, use of Saccharomyces and non-Saccharomyces yeasts as mixed starter cultures for inoculation of wine fermentations is of increasing interest for(More)
In the last few years there is an increasing interest on the use of mixed fermentation of Saccharomyces and non-Saccharomyces wine yeasts for inoculation of wine fermentations to enhance the quality and improve complexity of wines. In the present work Lachancea (Kluyveromyces) thermotolerans and Saccharomyces cerevisiae were evaluated in simultaneous and(More)
The use of non-Saccharomyces yeasts that are generally considered as spoilage yeasts, in association with Saccharomyces cerevisiae for grape must fermentation was here evaluated. Analysis of the main oenological characteristics of pure cultures of 55 yeasts belonging to the genera Hanseniaspora, Pichia, Saccharomycodes and Zygosaccharomyces revealed wide(More)
To further elucidate the impact of fermentative stress on Saccharomyces cerevisiae wine strains, we have here evaluated markers of oxidative stress, oxidative damage and antioxidant response in four oenological strains of S. cerevisiae, relating these to membrane integrity, ethanol production and cell viability during fermentation in high-sugar-containing(More)
Two yeast killer toxins active on spoilage yeasts belonging to the genus Dekkera/Brettanomyces are here described for the first time. The two toxins produced by Pichia anomala (DBVPG 3003) and Kluyveromyces wickerhamii (DBVPG 6077), and named Pikt and Kwkt, respectively, differ for molecular weight and biochemical properties. Interestingly, the fungicidal(More)
With the aim of developing new tools for the characterisation of wine yeasts, by means of databases available on-line we scanned the genome of Saccharomyces cerevisiae in search of potentially polymorphic targets. As we have previously observed for SED1, we found that other genes coding for cell wall proteins contain minisatellite-like sequences. A(More)
The origin of the Saccharomyces cerevisiae strains that are responsible for spontaneous grape must fermentation was investigated in a long-established industrial winery by means of two different approaches. First, seven selected components of the analytical profiles of the wines produced by 58 strains of S. cerevisiae isolated from different sites and(More)
In this work eighteen red yeasts were screened for carotenoids production on glycerol containing medium. Strain C2.5t1 of Rhodotorula glutinis, that showed the highest productivity, was UV mutagenized. Mutant 400A15, that exhibited a 280 % increase in β-carotene production in respect to the parental strain, was selected. A central composite design was(More)
The killer toxin secreted by Kluyveromyces phaffii (KpKt) is active against spoilage yeast under winemaking conditions and thus has potential applications in the biocontrol of undesired micro-organisms in the wine industry. Biochemical characterization and N-terminal sequencing of the purified toxin show that KpKt is a glycosylated protein with a molecular(More)