TECHNOLOGY FOCUS - BIOTECHNOLOGY - Preferred Method: In fermenting sugars derived from plant material into the fermentation product in the fermentation medium using the fermenting organism, the constituents are added to the fermentation medium before or during fermentation. The transketolase enzyme is present or added in an amount of 0.001-1000 U/ml of fermentation medium. The thiaminepyrophosphate is present or added in an amount of 0.001-1000 mM, preferably 10 mM of fermentation medium. Preferred Process: In producing the fermentation product from starch-containing material, (b) and (c) are carried out simultaneously or sequentially. The process further comprises, prior to (a), the steps of: reducing the particle size of starch-containing material; preferably by milling; and forming a slurry comprising the starch-containing material and water. Alternatively, producing the fermentation product from starch-containing material, comprises: (a) saccharifying starch-containing material at a temperature below the initial gelatinization temperature of the starch-containing material, and (b) fermenting using a fermenting organism, where one or more constituents comprising transketolase enzyme, thiaminepyrophosphate, or combinations are added to the fermentation medium. The starch-containing material comprises tubers, roots, stems, whole grains, corn, cobs, wheat, barley, rye, millet, milo, sago, cassava, tapioca, sorghum, rice, peas, beans, potatoes, yams, cereals, or mixtures. In producing the fermentation product from lignocellulose-containing material, the lignocellulose-containing material originates from materials selected from: corn stover, corn cobs, corn fiber, hardwoods, softwoods, cereal straw, switchgrass, bagasse, rice hulls, municipal solid waste, industrial organic waste, office paper, or mixtures. The fermenting organism is a yeast, preferably a strain of the genus Saccharomyces, especially Saccharomyces cerevisiae, or a strain of Pichia, preferably a strain of Pichia stipitis or Pichia pastoris. The fermentation product is an alcohol, preferably ethanol or butanol, where the fermentation product is recovered after fermentation. Preferred Organism: The fermenting organism is a microbial organism such as yeast or filamentous fungus, or a bacterium. EXAMPLE - No suitable example given.