NOVELTY - Method of liquefaction of solid lignocellulosic biomass, comprises: contacting the solid lignocellulosic biomass with a dicarboxylic acid to form an acidic mixture containing liquefied lignocellulosic biomass and unliquefied lignocellulosic biomass components; neutralizing the acidic mixture to form a neutralized mixture containing the liquefied lignocellulosic biomass and unliquefied lignocellulosic biomass components; and enzymatically hydrolyzing the unliquefied lignocellulosic biomass components in the presence of at least a portion of the liquefied lignocellulosic biomass components.    USE - The method is useful for liquefaction of lignocellulosic biomass under digestive action of dicarboxylic acids.    ADVANTAGE - The method is rapid and cost effective, and has improved flowability. The method reduces volume of biomass, and avoids excessive formation of degradation products.    DETAILED DESCRIPTION - INDEPENDENT CLAIMS are included for:    (1) a method-1 of liquefaction of wood biomass, comprising forming a mixture including an aqueous solution of a dicarboxylic acid and solid, particulate wood biomass, and incubating the mixture to cause hydrolysis of the wood biomass substantially by the dicarboxylic acid to form a flowable composition;    (2) a method-2 of liquefaction of lignocellulosic biomass, comprising forming a mixture including an aqueous solution of a dicarboxylic acid and solid, particulate lignocellulosic biomass, with the biomass solid present at a level of at least 10 wt.%, and incubating the mixture at a temperature and a flowable biomass composition in which at least 20% of the biomass solids have been converted to biomass components dissolved in the solution;    (3) a method-3 of treating lignocellulosic biomass, comprising contacting a mixture containing dicarboxylate anions, cations, liquefied lignocellulosic biomass components including xylose and glucose, and unliquefied lignocellulosic biomass components, with a cellulase enzyme to hydrolyze at least a portion of the unliquefied lignocellulosic biomass components; and    (4) a method-4 of manufacturing ethanol, comprising first contacting lignocellulosic biomass with a dicarboxylic acid to form an acidic mixture containing liquefied lignocellulosic biomass components, and unliquefied lignocellulosic biomass components, neutralizing the acidic mixture to form a neutralized mixture containing the liquefied lignocellulosic biomass components, contacting the neutralized mixture with a cellulase enzyme to liquefy at least a portion of the unliquefied lignocellulosic biomass and form an enzymatically-hydrolyzed mixture including glucose and xylose, and fermenting a medium containing the glucose and xylose from the enzymatically-hydrolyzed mixture to form ethanol.    DESCRIPTION OF DRAWING(S) - The figure shows a schematic view of method for liquefaction of solid lignocellulosic biomass.    Centrifuge (18)    Fermentor (19, 20)    Side stripper. (21)