NOVELTY - Hydrolyzing pretreated densified biomass particulates, comprises hydrolyzing at least one hydrolyzable densified biomass particulate (706) to produce a convertible sugar-containing stream. The densified biomass particulates are produced by: subjecting a plant biomass fibers to a pretreatment to cause at least a portion of lignin and/or hemicellulose contained within each fiber to move to an outer surface of the fiber to produce a pretreated tacky plant biomass fibers; and densifying the pretreated tacky plant biomass fibers to produce the hydrolyzable densified biomass particulates.    USE - The method is useful for hydrolyzing pretreated densified biomass particulates, which are useful: for producing a bioproduct that is biofuel (all claimed), and animal feed; and as components in solid materials, such as fiberboards and extruded fibrous building materials.    ADVANTAGE - The method: densifies the biomass fibers without using added binder; provides improved fermentation rates, as compared to fermentation rates achieved using non-densified plant biomass (all claimed); provides the hydrolyzable densified biomass particulate, which exhibits a smooth, non-flakey outer surface, increased resistance to deformation or degradation, an increased hardness and flowability, and an improved shelf life, and provides the animal feed having improved digestibility; prevents the lignin and/or sugars from being converted into furfural, hydroxymethyl furfural, and organic acids that could negatively affect microbial activity; and minimizes the energy consumption, hence it is cost effective.    DETAILED DESCRIPTION - Hydrolyzing pretreated densified biomass particulates, comprises hydrolyzing at least one hydrolyzable densified biomass particulate (706) to produce a convertible sugar-containing stream. The densified biomass particulates are produced by: subjecting a plant biomass fibers to a pretreatment to cause at least a portion of lignin and/or hemicellulose contained within each fiber to move to an outer surface of the fiber to produce a pretreated tacky plant biomass fibers; and densifying the pretreated tacky plant biomass fibers to produce the hydrolyzable densified biomass particulates, where the biomass fibers are densified without using added binder. INDEPENDENT CLAIMS are also included for:    (1) a product produced by the method; and    (2) a system comprising a hydrolyzing facility for hydrolyzing the hydrolyzable densified biomass particulates to produce the convertible sugar-containing stream.    DESCRIPTION OF DRAWING(S) - The figure shows a schematic view of a hydrolysis process using hydrolyzable densified particulates.    Container (702)    Water line (704A)    Hydrolyzable densified biomass particulate (706)    Suspension (708A)    Particles of suspension (709)