Production of fructose and ethanol from media with high sucrose concentrations by a mutant of Saccharomyces cerevisiae

Abstract The production of enriched fructose syrups and ethanol from a synthetic medium with high sucrose concentrations was studied in a batch process using Saccharomyces cerevisiae ATCC 36858. The results showed that the fructose yield was above 92% of theoretical values in synthetic media with sucrose concentrations between 180 g dm−3 and 726 g dm−3. Ethanol yield was about 82% in media with sucrose concentrations up to 451 g dm−3. A product containing 178 g dm−3 fructose, which represents 97% of the total sugar content, and 79 g dm−3 ethanol was obtained using a medium with 360 g dm−3 sucrose. The fructose fraction in the carbohydrates content in the produced syrups decreased with increases in the initial sucrose concentration. In a medium with initial sucrose concentration of 574 g dm−3, the fructose content in the produced broth was 59% of the total carbohydrates. Glycerol and fructo‐oligosaccharides were also produced in this process. The produced fructo‐oligosaccharides started to be consumed when the concentration of sucrose in the media was less than 30% of its initial value. Complete hydrolysis of these sugars was noticed in media with sucrose concentrations below 451 g dm−3. These findings will be useful in the production of ethanol and high fructose syrups using sucrose‐based raw materials with high concentrations of this carbohydrate. © 2001 Society of Chemical Industry