Methods for degrading or converting plant cell wall polysaccharides

Abstract

The present invention relates to methods for converting plant cell wall polysaccharides into one or more products, comprising: treating the plant cell wall polysaccharides with an effective amount of a spent whole fermentation broth of a recombinant microorganism, wherein the recombinant microorganism expresses one or more heterologous genes encoding enzymes which degrade or convert the plant cell wall polysaccharides into the one or more products. The present invention also relates to methods for producing an organic substance, comprising: (a) saccharifying plant cell wall polysaccharides with an effective amount of a spent whole fermentation broth of a recombinant microorganism, wherein the recombinant microorganism expresses one or more heterologous genes encoding enzymes which degrade or convert the plant cell wall polysaccharides into saccharified material; (b) fermenting the saccharified material of step (a) with one or more fermenting microoganisms; and (c) recovering the organic substance from the fermentation.

1 . A method for producing one or more organic substances, comprising:
 (a) saccharifying plant cell wall polysaccharides with an effective amount of a spent whole fermentation broth of a recombinant microorganism, wherein the recombinant microorganism expresses one or more heterologous genes encoding enzymes which degrade or convert the plant cell wall polysaccharides into saccharified material;   (b) fermenting the saccharified material of step (a) with one or more fermenting microoganisms; and   (c) recovering the one or more organic substances from the fermentation.   
     
     
         2 . The method of  claim 1 , wherein the plant cell wall polysaccharides are obtained from a source selected from the group consisting of herbaceous material, agricultural residue, forestry residue, municipal solid waste, waste paper, and pulp and paper mill residue. 
     
     
         3 . The method of  claim 1 , wherein the plant cell wall polysaccharide source is corn stover. 
     
     
         4 . The method of  claim 1 , wherein the one or more heterologous genes encode enzymes selected from the group consisting of a cellulase, endoglucanase, cellobiohydrolase, and beta-glucosidase. 
     
     
         5 . The method of  claim 1 , wherein the heterologous gene encodes a cellulase. 
     
     
         6 . The method of  claim 1 , wherein the heterologous gene encodes an endoglucanase. 
     
     
         7 . The method of  claim 1 , wherein the heterologous gene encodes a cellobiohydrolase. 
     
     
         8 . The method of  claim 1 , wherein the heterologous gene encodes a beta-glucosidase. 
     
     
         9 . The method of  claim 1 , wherein the one or more heterologous genes encode enzymes further selected from the group consisting of a glucohydrolase, xyloglucanase, xylanase, xylosidase, alpha-arabinofuranosidase, alpha-glucuronidase, acetyl xylan esterase, mannanase, mannosidase, alpha-galactosidase, mannan acetyl esterase, galactanase, arabinanase, pectate lyase, pectin lyase, pectate lyase, polygalacturonase, pectin acetyl esterase, pectin methyl esterase, alpha-arabinofuranosidase, beta-galactosidase, galactanase, arabinanase, alpha-arabinofuranosidase, rhamnogalacturonase, rhamnogalacturonan lyase, rhamnogalacturonan acetyl esterase, xylogalacturonosidase, xylogalacturonase, rhamnogalacturonan lyase, lignin peroxidase, manganese-dependent peroxidase, hybrid peroxidase, and laccase. 
     
     
         10 . The method of  claim 1 , wherein the one or more heterologous genes encode enzymes even further selected from the group consisting of an esterase, lipase, oxidase, phospholipase, phytase, protease, and peroxidase. 
     
     
         11 . The method of  claim 1 , wherein the spent whole fermentation broth of the recombinant microorganism is supplemented by the addition of one or more enzymes selected from the group consisting of a cellulase, endoglucanase, cellobiohydrolase, and beta-glucosidase. 
     
     
         12 . The method of  claim 1 , wherein the spent whole fermentation broth of the recombinant microorganism is supplemented by the further addition of one or more enzymes selected from the group consisting of a xyloglucanase, xylanase, xylosidase, alpha-arabinofuranosidase, alpha-glucuronidase, acetyl xylan esterase, mannanase, mannosidase, alpha-galactosidase, mannan acetyl esterase, galactanase, arabinanase, pectate lyase, pectin lyase, pectate lyase, polygalacturonase, pectin acetyl esterase, pectin methyl esterase, alpha-arabinofuranosidase, beta-galactosidase, galactanase, arabinanase, alpha-arabinofuranosidase, rhamnogalacturonase, rhamnogalacturonan lyase, rhamnogalacturonan, acetyl esterase, xylogalacturonosidase, xylogalacturonase, rhamnogalacturonan lyase, lignin peroxidase, manganese-dependent peroxidase, hybrid peroxidase, and laccase. 
     
     
         13 . The method of  claim 1 , wherein the spent whole fermentation broth of the recombinant microorganism is supplemented by the even further addition of one or more enzymes selected from the group consisting of an esterase, lipase, oxidase, phospholipase, phytase, protease, and peroxidase. 
     
     
         14 . The method of  claim 1 , wherein steps (a) and (b) are performed simultaneously in a simultaneous saccharification and fermentation. 
     
     
         15 . The method of  claim 1 , wherein the one or more organic substances are selected from the group consisting of an alcohol, organic acid, ketone, aldehyde, amino acid, gas, and a combination thereof. 
     
     
         16 . The method of  claim 15 , wherein the alcohol is arabinitol, butanol, ethanol, glycerol, methanol, 1,3-propanediol, sorbitol, or xylitol. 
     
     
         17 . The method of  claim 15 , wherein the organic acid is acetic acid, adipic acid, ascorbic acid, citric acid, 2,5-diketo-D-gluconic acid, formic acid, fumaric acid, glucaric acid, gluconic acid, glucuronic acid, glutaric acid, 3-hydroxypropionic acid, itaconic acid, lactic acid, malic acid, malonic acid, oxalic acid, propionic acid, succinic acid, or xylonic acid. 
     
     
         18 . The method of  claim 15 , wherein the ketone is acetone. 
     
     
         19 . The method of  claim 15 , wherein the aldehyde is furfural. 
     
     
         20 . The method of  claim 15 , wherein the amino acid is aspartic acid, alanine, arginine, asparagine, glutamine, glutamic acid, glycine, histidine, isoleucine, leucine, lysine, methionine, phenylalanine, proline, serine, threonine, tryptophan, tyrosine, or valine. 
     
     
         21 . The method of  claim 15 , wherein the gas is methane, hydrogen, carbon dioxide, and carbon monoxide.