COMPARATIVE ASSESSMENT OF THE LABORATORY SELECTED AND ACTIVE DRIED SACCHAROMYCES CEREVISIAE YEAST CULTURE IN BIOTECHNOLOGY OF THE BRANDY PRODUCTION
Authors: Bayraktar V. N. 
Published: March 2016

<p>Samples from different industrial grape cultivars were collected during the vintage season from the vineyard of the winery (the «Shabo» winery Company, located in the Odesa region, Ukraine). The following industrial cultivars of grapes were selected for the research: Chardonnay, Cabernet Sauvignon, Merlot, Sauvignon, Riesling Rhenish, Aligote, Rkatsiteli, Bastardo, Traminer, Telti Kuruk, Grinosh.</p> <p>The grape cultivars were cultivated on the sandy soils in the district located between the Black Sea and the Dnestrovsky estuary. Grape must derived from different grape cultivars was placed into sterile glass flasks to half of the 450ml flask volume. Each flask was carefully closed with a rubber stopper with an injection needle in it. During the fermentation process, it was necessary to remove carbon dioxide, which was present as a result of active anaerobic fermentation processes in the grape must. At the end of grape must fermentation, pure yeast cultures were isolated using traditional microbiological methods by consistent inoculation of a sample into a Petri dish with a few modifications of nutrient selective agar for yeast isolation and cultivation. Primary yeast isolation was carried out using Inhibitory Mold Agar medium (Becton Dickinson Company, USA).</p> <p>The yeast culture morphological properties were analyzed after the primary yeast culture isolation. Yeasts were identified by polymerase chain reaction (PCR) using universal yeast primers. After yeast culture identification, the next step in yeast cultivation was carried out on Wort Agar medium (Becton Dickinson Company, USA). Each isolated, and identified yeast culture was deposited in the Genebank of Japan, MAFF culture Collection, Tsukuba, Ibaraki, Japan and (NCYC) - Yeast Culture Collection (National Collection of Yeast Cultures, Institute of Food Research, Norwich, United Kingdom). Each yeast culture was tested for technological characteristics such as growth resistance to high temperature (+42°C) and low temperature (+6°C), growth at low pH 2.6–3.0 (acid resistance), growth in the presence of 5, 10, and 15% ethanol (ethanol resistance), and growth in the presence of high concentration potassium bisulfite (bisulfite resistance). Hydrosulfide synthesis (H<sub>2</sub>S gassing production) was studied in addition.</p> <p>Parameters of cellular metabolism in yeast suspension, such as concentration of nitrogen, protein, triglicerides, enzymatic activity and total sugar (which include glucose, fructose, and galactose) were determined. Macro- and micro-element concentrations in fermented grape must, which contained pure yeast culture was determined and included: potassium, sodium, calcium, phosphorus, magnesium, iron, chlorides. In addition to identifying parameters of macro- and micro- element concentration in grape must during and following fermentation based on a principle of photometric analysis, carried out using a biochemical analyser Respons-920 (DiaSys Diagnostic Systems GmbH, Germany).</p> <p>Laboratory selected <em>Saccharomyces cerevisiae </em>wine yeast showed high enzymatic activity with short lag phase. Since of fermentation started on third day concentration of Triglicerides, Protein (total), Potassium and Sodium increased and then level of Protein (total) on the 5th day of fermentation twice decreased. Trigliceride concentration on the 5th day of fermentation continued to increase. Concentration of Iron on the 5th day of fermentation increase in geometrical progression, concentration increase in 4-5 times. Contrary Chloride concentration on the 5th day of fermentation decreased in 3-4 times. Enzymatic activity on 3rd day of fermentation maximal for Lactate Dehydrogenase, Alanine aminotransferase, Aspartate aminotransferase, Phosphatase. Since of 5th day of fermentation Enzymatic activity for Lactate Dehydrogenase, Alanine aminotransferase, Aspartate aminotransferase 3-4 times. Especially level of Phosphatase activity very decreased in 6-7 times. Comparative assessment between our Laboratory selected <em>Saccharomyces cerevisiae</em> yeast culture and Dry active commercial <em>Saccharomyces cerevisiae</em> yeast culture did not showed any difference in enzymatic activity. Both groups showed high enzymatic activity on the third day from the start of fermentation and decreasing on the fifth day since of fermentation started.</p> <p><em> Key words: wine yeast, enzymatic activity, cellular metabolism</em><em>, </em><em>Saccharomyces cerevisiae</em><em>.</em><em></em></p>