TECHNOLOGY FOCUS - BIOTECHNOLOGY - Preferred Method: The enzymatic hydrolysis is performed under vacuum pressure less than 700 (preferably less than 50) mm Hg. The feedstock is subjected to activation, extraction, hydrolysis and physical modification prior to enzymatic hydrolysis. The activation, extraction, hydrolysis and physical modification is produced by autohydrolysis, acid hydrolysis, ammonia activation, disc refining, kraft pulping, organic solvent pulping, hot water pretreatment, ammonia percolation, lime pretreatment, caustic solvent pulping or alkali peroxide pretreatment (preferably autohydrolysis). After autohydrolysis, the feedstock is transferred to cyclone under vacuum and solid activated feedstock stream is obtained. The enzymatic hydrolysis involves first and second enzymatic hydrolysis processes and are performed under vacuum. The method further involves operating the first and second enzymatic hydrolysis processes under sufficient vacuum to reduce the level of inhibiting compound. The first enzymatic hydrolysis is operated under a vacuum of at least 700 mm Hg. The first enzymatic hydrolysis process uses first enzyme preparation and produces volatile component stream and low viscosity effluent stream which is subjected to second enzymatic hydrolysis using second enzyme preparation to produce sugar rich process stream. The beta -glucosidase and cellulase enzymes completely convert cellulose and oligosaccharides produced from the first enzymatic hydrolysis to monomeric sugars. Preferred Components: The first enzyme preparation has hemicellulase activity of 10-90% and cellulase activity of 90-10%. The first enzyme preparation acts upon the hemicellulose relative to cellulose in feedstock. The first enzyme preparation involves hemicellulase and cellulase enzymes, where hemicellulase enzymes act upon beta -1,4 linkage of xylose residue of xylan and beta -1,4 linkage of mannose residues of mannan. The second enzyme preparation acts on cellulose and cellobiose relative to xylan in feedstock. The second enzyme preparation involves beta -glucosidase and cellulase enzymes act upon beta -1,4 linkage of cellobiose and cellulose.    TECHNOLOGY FOCUS - ORGANIC CHEMISTRY - Preferred Components: The volatile components stream includes yeast, fungi, bacteria and enzyme inhibiting compound comprising furfural, hydroxymethylfurfural, organic acid, phenolic compound and other extractive. The concentration of furfural in sugar rich process stream is less than 0.2 (preferably less than 0.1, especially less than 0.05) wt./vol.%. The organic acid is acetic acid or formic acid. The concentration of acetic acid in sugar rich process stream is less than 0.4 (preferably less than 0.2, especially less than 0.1) wt./vol.%. EXAMPLE - No suitable example given.