NOVELTY - Production of ethanol from fibrous lignocellulosic raw material involves converting the raw material to solid fraction with an increased concentration of cellulose and liquid fraction containing solubilized hemicelluloses; hydrolyzing fibrous material with cellulase; simultaneously subjecting the modified material to hydrolysis with cellulase and ethanol fermentation; adding the liquid fraction to fermentation mixture; and recovering ethanol.    USE - The method is used for production of ethanol from fibrous lignocellulosic raw material (claimed), which is useful as biofuel.    ADVANTAGE - The method yields high concentration of ethanol at high fermentation rate and low production cost, thus economizes the ethanol production. The method provides high hydrolysis rate and high concentration by starting the hydrolysis at high raw material consistency at optimal conditions for the prehydrolyzing enzymes; avoids end product inhibition by continuing the main hydrolysis stage simultaneously with ethanol production from the hydrolyzed sugars by the yeast; and requires reduces amount of enzymes. Concentration and optional detoxification of the hemicellulose fraction improves the ethanol production rate and leads to high final ethanol concentration. Addition of the hemicellulose fraction at later phase reduces the inhibition of enzymes and organisms.    DETAILED DESCRIPTION - Production of ethanol from a fibrous lignocellulosic raw material involves:    (a) converting the raw material to a solid lignocellulosic fraction with an increased concentration of cellulose and a liquid fraction mainly containing solubilized hemicelluloses;    (b) hydrolyzing the fibrous lignocellulosic material at high consistency with a cellulase to provide a modified lignocellulosic material with increased flowability;    (c) simultaneously subjecting the modified lignocellulosic material to continued hydrolysis with cellulase and to ethanol fermentation in a fermentation mixture;    (d) continuing fermentation to convert an essential portion of the available carbohydrates into ethanol;    (e) adding the liquid fraction containing solubilized hemicelluloses to the fermentation mixture and continuing fermentation; and    (f) recovering ethanol from the fermentation mixture.