Study of the production of fructose and ethanol from sucrose media by Saccharomyces cerevisiae.
The production of ethanol and enriched fructose syrups from a synthetic medium with various sucrose concentrations using the mutant Saccharomyces cerevisiae ATCC 36858 was investigated. In batch tests, fructose yields were above 90% of theoretical values for the sucrose concentrations between 35 g/l and 257 g/l. The specific growth rates and biomass yields were from 0.218 to 0.128 h(-1) and from 0.160 to 0.075 g biomass/g of glucose and fructose consumed, respectively. Ethanol yields were in the range of 72 to 85% of theoretical value when sucrose concentrations were above 81 g/l. The volumetric ethanol productivity was 2.23 g ethanol/(l h) in a medium containing 216 g/l sucrose. Fructo-oligosaccharides and glycerol were also produced in the process. A maximum fructo-oligosaccharides concentration (up to 9 g/l) was attained in the 257 g/l sucrose medium in the first 7 h of the fermentation. These sugars started to be consumed when the concentrations of sucrose in the media were less than 30% of its initial values. The fructo-oligosaccharides mixture was composed of 6-kestose (61.5%), neokestose (29.7%) and 1-kestose (8.8%). The concentration of glycerol produced in the process was less than 9 g/l. These results will be useful in the production of enriched fructose syrups and ethanol using sucrose-based raw materials.
Atiyeh
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Department of Chemical Engineering, University of Ottawa, Canada. duvnjak@eng.uottawa.ca
Duvnjak
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D002851:Chromatography, High Pressure Liquid; D000431:Ethanol / Q000032:analysis / Q000378:metabolism*; D005632:Fructose / Q000032:analysis / Q000096:biosynthesis*; D005990:Glycerol / Q000032:analysis / Q000378:metabolism; D007700:Kinetics; D012441:Saccharomyces cerevisiae / Q000254:growth & development / Q000378:metabolism*; D013395:Sucrose / Q000378:metabolism*; D014312:Trisaccharides / Q000032:analysis / Q000096:biosynthesis
D014312:Trisaccharides; D005632:Fructose; D000431:Ethanol; C073432:6-kestose; D013395:Sucrose; D005990:Glycerol