TECHNOLOGY FOCUS - ORGANIC CHEMISTRY - Preferred Method: The liquid extracting step is carried out by first separating fibrous solids from the reaction mixture. The eluent is used to increase the level of extraction of the inhibitory compounds. The extracting step is carried out under a pressure of up to 350 psi. The liquid extracting step is carried out within a sealed mechanical compression device. The liquid extracting step is carried out under a pressure of up to 350 psi within a sealed mechanical compression device using an eluent to improve removal of the inhibitory compounds. The extracting step is carried out after the explosive decomposition and with a screw press, a filter, a filter press, a belt press, a centrifuge or a drainer. The liquid extracting step is carried out after the explosive decomposition and with a screw press, a filter, a filter press, a belt press, a centrifuge or a drainer with the simultaneous addition of an eluent. The liquid extracting step is carried before and after the explosive decomposition. The liquid extracting step is carried out before the explosive decomposition under pressure and after the explosive decomposition with the simultaneous addition of an eluent. The liquid extracting step is carried out with water as the eluent, for the removal of water soluble hydrolyzed hemicellulose and hemicellulose hydrolysis and degradation components and water soluble or suspended degradation products of it. The other compounds inhibitory to downstream cellulose hydrolysis and fermentation processes are removed in the extracting steps. The soluble xylose oligomers created in the hemicellulose hydrolysis during pretreatment are 30-90% of the hydrolyzed xylan in the pretreated biomass. The lignocellulosic biomass is pretreated by auto-hydrolysis or dilute acid catalysis. The liquid extracting is carried out with counter current washing using water as an eluent. The eluent origins are from recycle streams or recycled eluent water. The xylose equivalent content in the solids fraction after the liquid extracting step is xylose (4-6, preferably 6 wt./wt.%), for minimizing an amount of cellulolytic enzymes required to hydrolyze the reactive cellulose obtained. Preferred Components: The water soluble hydrolyzed hemicellulose and hemicellulose hydrolysis and degradation products include xylo-oligosaccharides, xylose, mannose-, galactose-, rhamnose- and arabinose-based oligomer and monomer sugars, acetic acid and formic acid. The other compounds are fatty acids, sterols, esters, or ethers. EXAMPLE - No suitable example given.