NOVELTY - Producing a composition comprising 5-6C saccharides from a biomass composition including cellulose, hemicellulose and/or lignocellulose, comprises (a) pretreating the biomass composition to produce a pretreated biomass composition by (i) hydrating the biomass composition in a non-neutral pH aqueous medium, (ii) performing mechanical size reduction of the hydrated biomass composition and (iii) heating the hydrated biomass composition for a time sufficient, and (b) hydrolyzing the pretreated biomass composition with one or more enzymes for a time sufficient.    USE - The method is useful for producing a composition comprising 5-6C-saccharides to produce fermentation and saccharification end-products and first and second population of saccharide polymers from a biomass (all claimed), which is used to extract carbohydrates, proteins and fats, where the end-products are biofuels, chemicals, liquid fuels, gaseous fuels, triacylglycerols, reagents, chemical feedstocks, chemical additives, processing aids, food additives, bioplastics, precursors, alcohol (e.g. ethanol, propanol, methanol and butanol), and carbonyl compound such as an aldehyde or ketone (e.g. acetone, formaldehyde and 1-propanal).    ADVANTAGE - The method produces high yield of fermentation and saccharification end-products using reduced enzyme loads in saccharification and fermentation processes, increase the efficiency of enzymes and provides effective enzymatic hydrolysis without the formation or release of large volumes of inhibitors.    DETAILED DESCRIPTION - Producing a composition comprising 5-6C saccharides from a biomass composition including cellulose, hemicellulose and/or lignocellulose, comprises: either (a) pretreating the biomass composition to produce a pretreated biomass composition comprising solid particles that are less than 10 mm in one or more size dimensions and a yield of 5C-monosaccharides and/or disaccharides that is at least 50% of a theoretical maximum by (i) hydrating the biomass composition in a non-neutral pH aqueous medium to produce a hydrated biomass composition, (ii) performing mechanical size reduction of the hydrated biomass composition to produce the solid particles and (iii) heating the hydrated biomass composition for a time sufficient to produce the pretreated biomass composition, and (b) hydrolyzing the pretreated biomass composition with one or more enzymes for a time sufficient; or (a1) processing the biomass composition to produce a pretreated biomass composition having solid particles, where the process comprises (i) hydrating and cutting the biomass composition by feeding the biomass composition to a vortex mixer, which comprises (1) an aqueous medium containing the acid, (2) one or more rotating cutters generating a vortex in the aqueous medium that mixes the biomass composition and the aqueous medium and pulls the biomass composition into the blades to produce a first cut biomass composition, (ii) dewatering the first cut biomass composition to produce a solids plug comprising 30 wt.% of solids, (iii) simultaneously heating and fine-cutting the solids plug by feeding the solids plug to a rotating cutter comprising a set of blades to fine cut the biomass plug to produce a second cut biomass composition comprising solid particles and a set of microholes, where steam is injected into the second cut biomass composition through the microholes to maintain a temperature at 160-180 degrees C and a pressure of 135 psig, (iv) heating the second-cut biomass composition for a time sufficient to produce at least an 80% yield of monomer and dimer 5C-saccharides, and (v) subjecting the solids plug to steam explosion to produce the first pretreated biomass composition having solid particles, (b1) optionally separating the soluble 5C-saccharides from the solids, (c1) adding water to the solids to from 5-25% solids by dry weight, (d1) adding 0.5-20 kg/kg enzymes and hydrolyzing the biomass for a time sufficient, and (e1) hydrolyzing the biomass for a time sufficient to produce the composition comprising 5-6C saccharides. INDEPENDENT CLAIMS are included for:    (1) a method-I for producing one or more fermentation end-products from the biomass, comprising the step (a) as above per se to produce a first population of saccharide polymers, and hydrolyzing and fermenting the pretreated biomass composition with one or more microorganisms for a time sufficient;    (2) a method-II for producing a first and second population of saccharide polymers from a biomass composition, comprising the step (a) as above per se and (b) as above per se to produce a second population of saccharide polymers;    (3) a system-I for producing the composition comprising 5-6C-saccharides, comprising (a) a pretreatment vessel for pretreating the biomass composition, where the vessel comprises (i) a hydration unit for hydration of the biomass composition in the aqueous medium, (ii) a size reduction unit for mechanical size reduction of the hydrated biomass composition to produce the solid particles, and (iii) a heating unit for heating the hydrated biomass composition, and (b) a hydrolysis unit for hydrolyzing the pretreated biomass composition with one or more enzymes;    (4) a system-II for producing one or more fermentation end-products from and the first and second population of saccharide polymers from biomass composition, comprising the steps (a) and (b) as above per se; and    (5) a system-III for producing saccharide polymers from the biomass composition, comprising (a) a first hydration unit for hydrating the biomass composition in the aqueous medium, (b) a first size reduction unit for reducing the biomass composition by a first mechanical size reduction, (c) a channel for dewatering the biomass composition, (d) a second size reduction unit for reducing the biomass composition, (e) a second hydration unit for hydrating the biomass composition in a non-neutral aqueous medium, and (f) a hydrolyzation unit for hydrolyzing the biomass composition by heating the biomass composition for a time sufficient to produce the saccharide polymers.