Intracellular glycerol influences resistance to freeze stress in Saccharomyces cerevisiae: analysis of a quadruple mutant in glycerol dehydrogenase genes and glycerol-enriched cells

Abstract

Glycerol is well known as a cryoprotectant similar to trehalose. However, there is little information about the effects of intracellular glycerol on the freeze-thaw stress tolerance of yeast. Through analysis of a quadruple-knockout mutant of glycerol dehydrogenase genes (ara1 Delta gcy1 Delta gre3 Delta ypr1 Delta) in Saccharomyces cerevisiae, we revealed that the decrease in glycerol dehydrogenase activity led to increased levels of intracellular glycerol. We also found that this mutant showed higher tolerance to freeze stress than wild type strain W303-1A. Furthermore, we demonstrated that intracellular-glycerol-enriched cells cultured in glycerol medium acquire tolerance to freeze stress and retain high leavening ability in dough even after frozen storage for 7 days. These results suggest the possibility of using intracellular-glycerol-enriched cells to develop better frozen dough.

Effect of Fermentation Temperature and Culture Medium on Glycerol and Ethanol during Wine Fermentation

“…These results are in accord with the requirement for glycerol production to counteract the hyperosmotic stress imposed by the high levels of sugar present at the IF stage (Van Dijck et al 2000). Glycerol production was much higher at 25°C than at 13°C in both culture media but was slightly higher at 13°C than at 25°C in the IF stage, which could be related to cold stress (Izawa et al 2004). Glycerol accumulation could induce yeast cells to adapt their physiology to lower than optimal temperatures.…”

“…Ethanol production was higher in grape must than in the synthetic medium at both temperatures. 2000a, Izawa et al 2004, Pérez-Torrado et al 2002. Little effort has been invested in understanding the links between ethanol and glycerol metabolism in grape must.…”

“…The production of glycerol balances the NADH/NAD intracellular ratio (Albers et al 1998), and glycerol, like trehalose, can act as a cryoprotectant (Izawa et al 2004). Glycerol is nonvolatile and therefore does not contribute to the aroma of wine, but it makes a significant contribution to the sweetness of wine, with a threshold taste level of 5.2 g/L in dry white wine, and can contribute to the body and fullness of wines (Noble and Bursick 1984).…”

“…There are many studies on the effects of environmental variables on glycerol and ethanol in synthetic media (Remize et al 2000a, Izawa et al 2004, Pérez-Torrado et al 2002. However, few studies on metabolism of glycerol and ethanol were analyzed in the different culture media.…”

Quality of Rapeseed Bio-Fuel Waste: Optical Properties

“…It is becoming more important for biodiesel producers to increase revenues by selling by-product of glycerol as well as finding use for other by-products. Purified glycerol has found many applications such as a substrate for chemical synthesis (Alavi Nijke, 2007;Aresta et al, 2009;Kim et al, 2007 Wolfson andDlugy, 2007), bioconversion (Chen et al, 2002;Kim et al, 2007;Nicol et al, 2012), substrate for food and cosmetic industry, production of surfactants (Jurado et al, 2012;Urata and Takaishi, 2002;Xu et al, 2011), production of biodegradable packaging (Liu et al, 2001), application in freezing (Izawa et al, 2004) or as a medium in medical care Nho et al, 2009). Other by-products such as crude glycerine or MONG fraction are not frequently reported in literature, their basic physicochemical properties are not described, there is no data on their possible application.…”