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

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 574g 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. (C) 2001 Society of Chemical Industry.