Kvasný průmysl (Mar 2000)
The inhibition of ethanol fermentation by high osmotic pressure.
Abstract
The work deals with investigation of the effect of high osmotic pressure on ethanol fermentation with yeast Saccharomyces cerevisiae. The inhibiting action of high osmotic pressure on the course of fermentation was investigated in media with the glucose content (100 g/l) as carbon source in the presence of sorbitol (0, 30, 60, 90, 120 and 150 g/l). The consequence of high osmotic pressure was the decrease of ethanol formation rate and glucose consumption, the increase both of biomass and produced ethanol. In the presence of a higher osmotic pressure the concentration of accumulated intracellular trehalose increased by 66% and the concentration of extracellular glycerol was 4,4 multiple. The combined influence of high osmotic pressure and externally added ethanol caused a further decrease of the fermentation rate and the amount of produced ethanol. The addition of glycine of cell walls during fermentation by increased osmotic pressure caused a moderate increase of fermentative activity of yeast, but a significant positive effect on obtained concentration of ethanol was not registered.The work deals with investigation of the effect of high osmotic pressure on ethanol fermentation with yeast Saccharomyces cerevisiae. The inhibiting action of high osmotic pressure on the course of fermentation was investigated in media with the glucose content (100 g/l) as carbon source in the presence of sorbitol (0, 30, 60, 90, 120 and 150 g/l). The consequence of high osmotic pressure was the decrease of ethanol formation rate and glucose consumption, the increase both of biomass and produced ethanol. In the presence of a higher osmotic pressure the concentration of accumulated intracellular trehalose increased by 66% and the concentration of extracellular glycerol was 4,4 multiple. The combined influence of high osmotic pressure and externally added ethanol caused a further decrease of the fermentation rate and the amount of produced ethanol. The addition of glycine of cell walls during fermentation by increased osmotic pressure caused a moderate increase of fermentative activity of yeast, but a significant positive effect on obtained concentration of ethanol was not registered.
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