TECHNOLOGY FOCUS - INORGANIC CHEMISTRY - Preferred Components: The catalyst comprises an enzyme and/or a non-enzymatic catalyst.    TECHNOLOGY FOCUS - INSTRUMENTATION AND TESTING - Preferred Method: The mixture is separated using a mechanical device, a filter, a membrane, or a tangential flow filtration device. The conditions of high shear agitation comprise treating the biomass with a high shear/milling mixing device comprising a rotor and a stator, where the gap setting between the rotor and stator is 0.1-2.2 ml. Preferred Components: The mechanical device is a centrifuge, a press, or a screen.    TECHNOLOGY FOCUS - ORGANIC CHEMISTRY - Preferred Components: The biomass comprises glucan and at least 80% of the glucan in the biomass is hydrolyzed to glucose in 6-24 hours. The biomass comprises at least 10 wt.% solids prior to the contacting step. Preferred Method: The conditions in the step (a) produce a biomass particle size where at least 80% of the particles have a particle size of 2-200 mu m. The amount of glucan converted is at least 10% greater than the amount of glucan converted when compared to a method that does not comprise the separating step. The separating step is carried out: at 2-4 hours or 4-6 hours after the contacting step; and when 30-60% of the glucan is converted. The incubating step is carried out for 8-20 hours under conditions of high shear agitation. The method further comprises contacting the solids from step (c) with additional biomass in a batch, semi-batch, or continuous process. The sugars from the liquid stream in step (b) and/or the additional sugars from step (c) are processed into ethanol, biofuels, biochemicals, or other chemical products. The hydrolyzed components from the step (c) contain decreased concentrations of contaminants compared to biomass that is not treated under the conditions as in step (a). The step of contacting the biomass with a catalyst to hydrolyze components of the biomass to sugars is carried out after the application of high shear. The method further comprises (d) separating the liquid stream produced in (b) into a second liquid stream comprising sugars and a second solid stream comprising solids and (e) incubating the second solids under conditions suitable to hydrolyze components of the solids to sugars to produce additional sugars. In the method, prior to the pretreatment step (a), the biomass is mixed with water to provide a biomass/water mixture. EXAMPLE - No suitable example given.