NOVELTY - Hydrolyzing lignocellulosic material comprises (a) pretreating lignocellulosic material in an aqueous medium for depolymerization of hemicellulose to produce a slurry, (b) optionally subjecting the pretreated lignocellulosic material to an enzyme hydrolysis step, (c) subjecting the slurry resulting from step (a) to a first separation process, (d) processing obtained aqueous phase to recover xylooligosaccharide, (e) subjecting the undissolved material resulting from step (c), and (f) subjecting the slurry resulting from step (e) to a second separation process to obtain an aqueous phase.    USE - The lignocellulosic material is useful for recovering fermentable sugars e.g. glucose and xylose to manufacture biofuels and renewable chemical feedstock in a biorefinery.    ADVANTAGE - The lignocellulosic material provides cost-effective process for pretreating lignocellulosic biomass in the recovery of fermentable sugars, exhibits mechanical milling operation to achieve a size reduction to increase the efficiency of infiltration of the chemical reagents used in the subsequent hydrolysis reactions, and efficiently recovers and uses six-carbon and five-carbon sugars along with value-added oligosaccharides such as xylooligosaccharides from lignocellulosic biomass so that the cost of manufacturing biofuels and renewable chemical feedstock is lowered, thus providing flexibility and robustness and maximizing the profitability in the operation of the biorefinery.    DETAILED DESCRIPTION - Hydrolyzing lignocellulosic material comprises either: (a) pretreating the lignocellulosic material in an aqueous medium at a temperature and pressure optimal for depolymerization of hemicellulose to produce a slurry without any noticeable impact on the cellulose and lignin components in the lignocellulosic material, (b) optionally subjecting the pretreated lignocellulosic material to an enzyme hydrolysis step, (c) subjecting the slurry resulting from step (a) to a first separation process to obtain an aqueous phase containing products resulting from the depolymerization of hemicellulose in step (a) and undissolved material containing cellulose and lignin, (d) processing the aqueous phase obtained in step (c) to recover xylooligosaccharide from xylose monomer, (e) subjecting the undissolved material resulting from step (c) to a second hydrolysis step under conditions that facilitates the depolymerization of cellulose to a slurry comprising glucose, and (f) subjecting the slurry resulting from step (e) to a second separation process to obtain an aqueous phase containing glucose and a solid fraction comprising primarily of lignin; or (a) providing cellulose pulp that has hemicellulose that is predominantly xylan, and a lignin content that is less that 1 wt.%, (b) extracting the hemicellulose from the pulp as in step (a) into caustic solution for forming hemi caustic solution and a washed pulp, (c) separating the hemi caustic solution into a concentrated hemicellulose solution and concentrated caustic solution, (d) acidifying concentrated hemicellulose solution and recovering hemicellulose in a concentrated form, (e) subjecting hemicellulose recovered in step (d) to enzymatic hydrolysis to produce xylooligosaccharides, and (f) subjecting the washed pulp obtained in step (b) to enzymatic hydrolysis to produce glucose.