A process for production of C5 and C6 sugar enriched syrups from lignocellulosic biomass and fermentation products therefrom is described. A lignocellulosic biomass is treated with a C.sub.1-C.sub.2 acid (e.g., acetic acid) with washing thereof with a C.sub.1-C.sub.2 acid miscible organic solvent, (e.g., ethyl acetate). A soluble hemicellulose and lignin enriched fraction is obtained separately from a cellulose pulp enriched fraction and lignin is removed from the soluble hemicellulose fraction. These fractions contain acylated (e.g., acetylated) cellulose and hemicellulose, which are deacylated by treatment with an alkali and/or with an acetyl esterase enzyme. The deacylated fractions are then digested with suitable cellulolytic and/or hemicellulolytic enzymes, preferably in the presence of non-ionic detergent to yield the C5 and C6 enriched syrups. Also described are method of fermentation of the syrups to make ethanol to at least 7% w/vol by separate hydrolysis and fermentation (SHF) or simultaneous hydrolysis and fermentation (SSF) methods.
STATEMENT OF FEDERAL SPONSORED RESEARCH
 This invention was made with government support under department of Energy Grant No: DE-EE0002870. The federal government has certain rights in this invention.