Method for production of fermentable sugars from biomass

A process of production of fermentable sugars from biomass using multi-step multi-enzyme system, the process comprising:

• a. mixing biomass with 5% to 10% w/v alkali having pH in the range of 12-14 at a temperature ranging from 50° C. to 200° C. under 1.0 to 20 bar pressure for a time of 5 minutes to 2 hrs to obtain a biomass slurry;
• b. filtering said biomass slurry to obtain filtrate comprising hemicellulose;
• and residue comprising cellulose;
• c. treating the filtrate with alcohol to obtain a precipitate containing hemicelluloses;
• d. washing the residue from step (b) with water to remove residual alkali to obtain cellulose;
• e. washing the precipitate to obtain hemicelluloses;
• f. treating the hemicellulose from step (e) and the cellulose from step (d) with endo-glucanases, exo-glucanases, endo-xylanases, exo-xylanases, mannanases and galactanases at a temperature of 50° C. and pH 5 to obtain a hydrolysate;
• g. separating the hydrolysate from the enzymes used in step (f) to obtain a solution comprising oligosaccharides, disaccharides and monosugars;
• and
• h. treating the solution with xylosidases, mannosidases and glucosidases to obtain the fermentable sugars.