TECHNOLOGY FOCUS - BIOLOGY - Preferred Components: The enzymes used in (B) and (C) have a broad spectrum of cellulases; are active at 30 - 90 degreesC; and have at least two activities selected from cellobiohydrolase, endoglucanase, beta-glucosidase activities and hemicellulase activities. The fermenting organism (preferably yeast) is able to produce ethanol from the major lignocellulose derived sugars at 30 - 70 degreesC. The fibrous lignocellulosic raw material contains carbohydrates; and originates from softwood, hardwood, dedicated crops, agricultural waste, waste paper or a side stream from the forest industry.    TECHNOLOGY FOCUS - ORGANIC CHEMISTRY - Preferred Process: The raw material is subjected to steam-explosion in step (A). The hydrolysis of step (B) is carried out at a consistency of 10 - 25 dry wt.%, pH 4 - 6, and temperature higher than that of the hydrolysis and fermentation of step (C) (preferably 40 - 90 degreesC for 0.5 - 24 hours). The hydrolysis in steps (B) and (C) is carried out with different cellulase preparations independently. (C) Is carried out at 30 - 70 degreesC. The enzyme used in (C) is capable of hydrolyzing the lignocellulosic material present in steps (C) - (E). The fermentation step is carried out in the presence of a fermenting organism, capable of fermenting major lignocellulose derived sugars (preferably hexoses and pentoses). The fermentation is carried out at 30 - 70 degreesC, and hydrolysis is continued with a second enzyme, which is active at this temperature for 6 - 96 hours. The liquid fraction containing dissolved hemicellulose is added to the fermentation mixture when at least 50 wt.% of the available hexoses and pentoses has been fermented to ethanol. The concentration of the liquid fraction is increased after (A) and before step (D). The hemicellulose fraction is added at a dry weight concentration of 5 - 60%. The liquid fraction is subjected to a detoxification operation to free the hemicellulose fraction from substances that may inhibit fermentation. The inhibitors are removed by stripping, evaporation, ion exclusion, resin, or the charcoal treatment method. The concentrated hemicellulose fraction is added during 10 minutes - 48 hours, after which fermentation is continued for further 6 - 72 hours at 30 - 70 degreesC and pH 4 - 6. The cellulases used for in both hydrolysis steps are of the same origin and designed for efficient hydrolysis of the lignocellulosic material in the whole process. The process involves hydrolyzing the fibrous lignocellulosic material at a consistency of 10 - 40 dry wt.% with cellulase to hydrolyze 20 - 80% of the carbohydrates to provide the modified lignocellulosic material having increased flowability; simultaneously subjecting the modified lignocellulosic material to continued hydrolysis with cellulase and to ethanol fermentation; adding the liquid fraction to the fermentation mixture when at least 50 wt.% of the available hexoses and pentoses have been fermented to ethanol, and continuing fermentation; and recovering ethanol from the fermentation mixture. EXAMPLE - Softwood was steam pre-treated and divided into two fractions: a solid fraction containing mainly cellulose, and a soluble fraction containing mainly the hemicellulose sugars. The solid fraction was filtrated, washed and suspended to form a fiber suspension with 18% of dry matter. The fiber was pre-hydrolyzed with commercial enzyme preparations at 50 degreesC. The hydrolysis conditions were: 16.2 dry wt.% solids in acetate buffer, pH 5, and the enzyme preparations used were Celluclast 1,5 L FG, 20 FPU/g dry weight, and Novozym 188, with beta-glucosidase dosage 200 nkat/g dry weight. After pre-hydrolysis, approximately 20% of the cellulose in fiber fraction had been hydrolyzed to glucose. After 20 hours, the pre-hydrolyzate was tempered to 30 degreesC and inoculated with Saccharomyces cerevisiae (strain VTT-B-03339). The hemicellulose filtrate containing inhibitors and toxic compounds for yeast was added either:    (a1) in the beginning of the hydrolysis (resulting in 13.3 wt.% solids in hydrolysis);    (b1) in the beginning of the fermentation at the same time as the yeast; or    (c1) by two consequent additions after the beginning of the fermentation.    A control treatment was carried out similarly using the unwashed steam pre-treated material containing the hemicellulose fraction, i.e. the material with no separation of hemicellulose fraction, and with no washing. The ethanol concentrations (%) produced in the yeast fermentation were 0.2, 2.6, and 3.2 under conditions (a1), (b1) and (c1) respectively; and 0.15 in the control treatment method. The results showed that the gradual addition of the toxic filtrate at the latter stage of the fermentation improved the yield and production rate.