TECHNOLOGY FOCUS - BIOLOGY - Preferred Components: The cellulase enzymes are produced by microorganisms consisting of mushrooms belonging to Trichoderma, Aspergillus, Penicillium or Schizophyllum or anaerobic bacteria belonging to Clostridium. The alcohol microorganism consists of Saccharomyces, Saccharomyces cerevisiae, Schizosaccharomyces pombe, Saccharomyces uvarum, Saccharomyces diastaticus, Kluyveromyces fragilis, Candida shehatae, Pichia stipitis, Pachysolen tannophilis, Zymomonas mobilis, Clostridium, and Escherichia coli.    TECHNOLOGY FOCUS - ORGANIC CHEMISTRY - Preferred Method: The method comprises contacting the stream enriched in solid material with the liquid stream, and then separating the liquid stream of the solid material. The step (b) is performed in a first reactor, and the step (c) is performed in a second reactor that is different from the first reactor. The step (b) and the step (c) are simultaneously performed in the same reactor. The method comprises performing a steam explosion of biomass by compressing, and performing relaxation of the biomass in mixture with water and an acid compound. Preferred Components: The liquid stream of step (e) consists of fresh water, and comprises a part of vinasse stream. The liquid stream enriched in fermentation product is present at a flow rate of 50-1500 wt.% to the flow rate of the pretreated substrate. The stream enriched in solid material comprises 15-55 wt.% of solid material. The fermentation wine depleted of solid material comprises 15 wt.% of the solid material. EXAMPLE - 89.80 tone/hour of Wheat straw was milled on a grid (50 mm) and impregnated with 0.7 g/l diluted sulfuric acid. A solid/liquid separation was performed to recycle impregnation liquor. The pretreatment step by steam explosion was carried out at 200 degrees C in a continuous configuration using a short residence time. The medium was suddenly expanded to an atmospheric pressure of 1.3. The pretreated substrate was fed to the enzymatic hydrolysis reactor. 114.3 tones/hour of Water was mixed with pretreated substrate. After 10 hours operation, the liquefied mixture is fed to an enzymatic hydrolysis unit. The enzymatic hydrolysis and conversion was performed using cellulase enzymes and the fermentation was performed using Saccharomyces cerevisiae. The wine was sent to a decanter, and the solid material such as lignin was separated from the wine before the recovering of ethanol. The resultant product was extracted and worked up to give 74890 tones of ethanol.