TECHNOLOGY FOCUS - ORGANIC CHEMISTRY - Preferred Process: In producing fermentable sugars from whole biomass, the feedstock comprises sugarcane, bagasse, and straw. The feedstock comprises energy cane, and corn and corn stover. The non-lignocellulosic sugars comprise starch, sucrose, glucose, fructose, and/or sucrose which forms glucose and fructose during the process, and where the glucose is substantially recovered in step (f). The acid catalyst includes a sulfur-containing acid, where the sulfur-containing acid is selected from sulfur dioxide, sulfurous acid, sulfur trioxide, sulfuric acid, lignosulfonic acid, and combinations. The acid catalyst does not include a sulfur-containing acid. The solvent for lignin is selected from linear alcohols, cyclic alcohols, aromatic alcohols, polyols, ketones, ethers, ionic liquids, and combinations. The effective hydrolysis conditions in step (d) include hydrolysis catalyzed by lignosulfonic acids derived from step (b). The effective hydrolysis conditions in step (d) include hydrolysis catalyzed by enzymes. The cellulose-rich solids are recovered as a cellulose material or precursor. The cellulose-rich solids are hydrolyzed to glucose. Alternatively, producing fermentable sugars from whole sugarcane or energy cane involves: (a) providing whole sugarcane or energy cane as feedstock; (b) in a digestor, fractionating the feedstock under effective fractionation conditions in the presence of sulfur dioxide, a solvent for lignin, and water, to produce a liquor containing cellulose-rich solids, dissolved lignin, dissolved hemicellulose, and dissolved sucrose; (c) substantially removing the cellulose-rich solids from the liquor; (d) hydrolyzing the dissolved hemicellulose contained in the liquor, under effective hydrolysis conditions, to produce a hydrolyzed liquor comprising hemicellulosic monomers and the sucrose, and/or glucose and fructose derived from the sucrose; (e) hydrolyzing the cellulose-rich solids to produce glucose; and (f) recovering the hydrolyzed liquor and the glucose as fermentable sugars. In a second alternative case, producing fermentable sugars from whole corn involves: (a) providing whole corn as feedstock; (b) in a digestor, fractionating the feedstock under effective fractionation conditions in the presence of sulfur dioxide, a solvent for lignin, and water, to produce a liquor containing cellulose-rich solids, starch, dissolved lignin, and dissolved hemicellulose; (c) substantially removing the cellulose-rich solids from the liquor; (d) hydrolyzing the dissolved hemicellulose and the starch contained in the liquor, under effective hydrolysis conditions, to produce a hydrolyzed liquor comprising hemicellulosic monomers and starch-derived glucose; (e) hydrolyzing the cellulose-rich solids to produce cellulose-derived glucose; and (f) recovering the hemicellulosic monomers, the starch-derived glucose, and the cellulose-derived glucose as fermentable sugars. EXAMPLE - No suitable example given.