Screening of strains of Saccharomyces cerevisiae for ethanol fermentation of very-high-gravity subtrates

摘要

A strain usable for fermentation of highly concentrated substrates by very-high-gravity fermentation technology (VHG) was selected on the basis of fermentation activity of the strains at high initial substrate concentrations and in the presence ofexogenously added ethanol.The capacity of 35 distillery,baker's and wine strains of yeasts Saccharomyces cerevisiae to ferment high glucose concentrations was studied in a medium without ethanol addition and with addition of 10% ethanol by volume.Three strains were selected on the basis of biomass increments,degree of glucose utilization and concentration of produced ethanol.Maximum concentration of produced ethanol and ethanol productiovity expressed as the amount of produced ethanol in a given volumewithin a time interval were compared in media with increasing glucose concentrations (250,300,350 and 400g/l).The highese ethanol concentration (74.4g/l) and highest ethanol productivity (1.38g/l/h) was recorded in strain Pz 90 at a glucose concentrationof 400 g/l in medium.An increase in biomass concentration (up to 18 g/l)led to further increase in ethanol productivity (2.84g/l).