Biomass liquefaction processes, and uses of same

Abstract

Described are processes for the liquefaction of lignocellulosic biomass under the digestive action of dicarboxylic acid(s). Such digests can exhibit enhanced flowability, reduced volume, and significant biomass conversion to dissolved components, and can in some embodiments be further liquefied by contact with an enzyme. Products resultant of these steps can be used for their sugar content to manufacture biofuels or other products.

1 - 9 . (canceled) 
     
     
         10 . A method for 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 for a period of time and under conditions effective to cause hydrolysis of the wood biomass substantially by the dicarboxylic acid to form a flowable composition.   
     
     
         11 . The method of  claim 10 , wherein the solid, particulate wood biomass comprises elongate fibrous particles having an average length of at least 1 mm. 
     
     
         12 . The method of  claim 10 , wherein the dicarboxylic acid is selected from maleic acid, succinnic acid, and oxalic acid. 
     
     
         13 . The method of  claim 12 , wherein the dicarboxylic acid is maleic acid. 
     
     
         14 . The method of claim  1 , wherein said adding is conducted so as to achieve an initial loading of the wood biomass of at least 15% w/w. 
     
     
         15 . The method of  claim 10 , wherein said incubating is conducted sufficiently to liquefy at least 10% by weight of the wood biomass dry matter. 
     
     
         16 . The method of  claim 10 , also comprising the step of neutralizing the flowable composition to form a neutralized composition. 
     
     
         17 . The method of  claim 10 , wherein the dicarboxylic acid constitutes greater than 50%, on a molar basis, of the organic protic species in the aqueous solution. 
     
     
         18 . The method of  claim 10 , wherein the aqueous solution is essentially free of organic protic species other than the dicarboxylic acid. 
     
     
         19 . A method for 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% by weight in the mixture; and   incubating the mixture at a temperature and for a period of time sufficient to form a flowable biomass composition in which at least about 20% of the biomass solids have been converted to biomass components dissolved in the solution.   
     
     
         20 . The method of  claim 19 , wherein the incubating is effective to increase the bulk density of the solids by at least about 15%. 
     
     
         21 . The method of  claim 19 , wherein the incubating is effective to convert at least 70% of the hemicellulose present in the biomass to monomeric xylose. 
     
     
         22 . The method of  claim 19 , wherein said incubating occurs in a first vessel, and also comprising the step of pumping the flowable biomass through a conduit to a second vessel. 
     
     
         23 . A method for 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 for a period of time and under conditions effective to hydrolyze at least a portion of the unliquefied lignocellulosic biomass components.   
     
     
         24 . The method of  claim 23 , wherein the dicarboxylate anions are maleate  5  anions. 
     
     
         25 . The method of  claim 23 , wherein the lignocellulosic biomass components are wood components. 
     
     
         26 . The method of  claim 23 , wherein said contacting is conducted with the cellulase enzyme at a loading less than about 2 milligrams per gram of the lignocellulosic biomass on a dry weight basis. 
     
     
         27 . The method of  claim 23 , also comprising isolating a solids-free liquid including the xylose and the glucose after said contacting. 
     
     
         28 . The method of  claim 23 , also comprising:
 forming said mixture by incubating particulate lignocellulosic biomass in contact with a liquid medium comprising a dicarboxylic acid.   
     
     
         29 . A method for manufacturing ethanol, comprising:
 first contacting lignocellulosic biomass with a dicarboxylic acid for a period of time and under conditions effective to form an acidic mixture containing liquefied lignocellulosic biomass components including glucose and xylose, and unliquefied lignocellulosic biomass components;   neutralizing the acidic mixture to form a neutralized mixture containing the liquefied lignocellulosic biomass components including glucose and xylose, and unliquefied lignocellulosic biomass components;   second contacting the neutralized mixture with a cellulase enzyme for a period of time and under conditions effective 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.   
     
     
         30 . The method of  claim 29 , wherein the dicarboxlic acid is maleic acid. 
     
     
         31 . The method of  claim 29 , wherein the lignocellulosic biomass comprises wood. 
     
     
         32 . The method of  claim 29 , wherein said second contacting and fermenting steps occur simultaneously in a single chamber.