Use of the yeast Kluyveromyces marxianus for the production of innovative wines and the improvement of their quality
Tuesday 16 May - National Hall
Module managed in collaboration with HTS Enologia
The speakers will be:
Daniele Oliva,
Dirigente U.O. Microbiologia applicata e Biotecnologie,
Istituto Regionale del Vino e dell’Olio, Regione Sicilia
Diego De Filippi,
Direttore Tecnico e R&D presso HTS
Use of the yeast Kluyveromyces marxianus for the production of innovative wines and the improvement of their quality
Daniele Oliva, biologist IRVO
From 2009 to 2012 IRVO isolated, identified and characterized yeast strains from grapes sampled on the small island of Linosa, where there are no wineries and therefore the possibility of territory contamination by industrial strains is minimal. By traditional microbiological methods, 3805 yeast colonies were isolated, then distinguished by molecular methods in 17 different species. 544 isolates were analyzed for the main oenological characteristics such as fermentation vigour with and without sulphites, sugar consumption and production of alcohol, volatile acidity, hydrogen sulphide, glycerol and beta-glucosidase. These analyses identified a strain of Kluyveromyces marxianus as the most interesting candidate for the production of innovative wines. Although this species was originally isolated from grapes and its enzymatic activities are used in winemaking, this yeast has rarely been used as a co-starter.
From 2012 to 2016, the K. marxianus Km L2009 strain was characterized and used both in laboratory-scale fermentations and in experimental winery. The Km L2009 strain showed growth ability even in the presence of 40 mg/L of sulphites and 6% ethanol. Gas chromatographic analysis demonstrates that wines, produced by mixed fermentation with Saccharomyces cerevisae, contain significantly higher quantities of free monoterpenes and aliphatic esters than wines produced only by commercial strains of Saccharomyces cerevisiae. Differences in the composition of volatile organic compounds resulted in sensorially distinct wines. With these results it is possible to state that even within the K. marxianus species it is possible to select strains able to improve the aromatic quality of wines.
A new non-Saccharomyces yeast for the production of highly aromatic white and rosé wines
The first strain of Kluyveromyces marxianus (Km L2009) for oenological use
Diego De Filippi, HTS Enologia
This research work evaluated the possibility of using in industrial conditions a non-Saccharomyces yeast strain belonging to a species not yet present on the oenological yeast market anywhere in the world: Kluyveromyces marxianus, named Km L2009.
The performance of this yeast strain, selected by IRVO on the island of Linosa in Sicily, had already been previously evaluated in sequential fermentations on an experimental scale and in microvinification. The results highlighted the potential of this strain to produce intensely aromatic white wines. It was therefore decided to evaluate this propensity on white grape varieties (Grillo and Moscato) in real vinification conditions managed both in the traditional way and with the use of automated fermentation management systems, also evaluating the compatibility of the Km L2009 strain with several strains of S. cerevisiae.
The possibility of reproducing the strain in question on an industrial scale was also evaluated.
All the wines obtained during the tests were evaluated through chemical-physical and sensorial analyzes which demonstrated how the wines produced with the Km L2009 strain were preferred by tasters for their aromatic intensity compared to wines produced with traditional commercial yeasts.
