Saccharomyces cerevisiae Inoculum Heat Shock Treatment – New Method for Enhanced Glycerol Production in Wine

The present research was focused on developing a new method to enhance glycerol production for the benefit of ethanol reduction in alcohol fermentation of grape must metabolism using thermal shocks on inoculum suspension of Saccharomyces cerevisiae yeast cells. The influence of applied heat shocks at intervals of 10, 20 and 30 minutes at 45 °C is presented. The significance of this method is in the homogenization of the quality and efficiency of the resistible cells that survived thermal shock. They represent a new active biomass that includes also a memory effect of heat exposure that enables increasing the production of glycerol from 6.3 to 8.4 g L–1 at 18 °C and 7.8 to 10.3 g L–1 at 22 °C. In the same experiments, the concentration of ethanol decreased from 89 to 81 g L–1 at 18 °C and from 104 to 97 g L–1 at 22 °C. These results represent a new and easily applicable method for high glycerol production at reduction of ethanol even in large scale

Submerged Cultivation of Ganoderma lucidum Biomass in Stirred Tank Reactor

European isolated strain Ganoderma lucidum, its biomass formation, intracellular and extracellular polysaccharide production in batch and repeated fedbatch cultivation, were studied. The best fed batch results were obtained in the first feeding at 141 h at productivity of biomass Px = 0.016 g g–1 h–1, intracellular Pi = 0.010 g g–1 h–1, extracellular polysaccharides Pe = 0.007 g g–1 h –1, and percent value of polysaccharides per cell dry weight Pi/x = 5.0 % and Pe/x = 3.0 %. Although four feedings increased the amount of fungal biomass by 42.66 %, productivities of fungal polysaccharides Pi = 0.010 g g–1 L–1 and Pe = 0.011 g g–1 L–1 showed that at the fourth feeding, the biomass was already exhausted and polysaccharide production was reduced. Therefore, 210 h batch cultivation with Px = 0.095 g g–1 L–1, Pi = 0.078 g g–1 L–1 at Pi/x = 33 % and extracellular polysaccharides Pe = 0.095 g g–1 L–1 at Pe/x = 6.8 %, was found to be the best mode for G. lucidum fungal biomass and polysaccharides production. Non-Newtonian cultivation broth rheology was found to be influenced entirely by the concentration and morphology of the biomass

The Role of Redox Potential Measurement in Oak Barrel Wine Maturation

Redox potential measurement was efficiently used for monitoring the two-year maturation process of cultivar Blau Fränkisch wine in 225-L oak barrels. Redox potential of maturing wine was measured at six levels from the top to the bottom of the barrel. During the process of wine maturation, the formation and heterogeneity of redox layers, as well as the formation of various oxidoreductive zones were indicated. The end of barrel maturation process was represented with homogeneity of all redox zones where no differences in all measured levels were indicated

Influence of temperature shock on the glycerol production in cv. Sauvignon blanc fermentation

Research NoteRepeating heat shocks applied during the exponential growth phase, led to high glycerol concentrations up to 10.0 g·l-1 or higher. Using one heat shock 8.2 g·l-1 or 2.2 g·l-1 more glycerol was produced, while with a double heat shock 10.0 g·l-1 or 4.0 g·l-1 more glycerol was produced. Using this procedure even higher amounts of glycerol could be produced. These results could be effectively applied in wine technology.

Saccharomyces cerevisiae Inoculum Heat Shock Treatment – New Method for Enhanced Glycerol Production in Wine

The present research was focused on developing a new method to enhance glycerol production for the benefit of ethanol reduction in alcohol fermentation of grape must metabolism using thermal shocks on inoculum suspension of Saccharomyces cerevisiae yeast cells. The influence of applied heat shocks at intervals of 10, 20 and 30 minutes at 45 °C is presented. The significance of this method is in the homogenization of the quality and efficiency of the resistible cells that survived thermal shock. They represent a new active biomass that includes also a memory effect of heat exposure that enables increasing the production of glycerol from 6.3 to 8.4 g L–1 at 18 °C and 7.8 to 10.3 g L–1 at 22 °C. In the same experiments, the concentration of ethanol decreased from 89 to 81 g L–1 at 18 °C and from 104 to 97 g L–1 at 22 °C. These results represent a new and easily applicable method for high glycerol production at reduction of ethanol even in large scale