Fungal xylanases and xylosidases

Abstract

The present invention provides fungal xylanase and/or xylosidase enzymes suitable for use in saccharification reactions. The present invention provides xylanase and xylosidase enzymes suitable for use in saccharification reactions. The present application further provides genetically modified fungal organisms that produce xylanase(s) and/or xylosidase(s), as well as enzyme mixtures exhibiting enhanced hydrolysis of cellulosic material to fermentable sugars, enzyme mixtures produced by the genetically modified fungal organisms, and methods for producing fermentable sugars from cellulose using such enzyme mixtures. In some embodiments, the xylanase and xylosidase enzyme(s) are M. thermophila enzymes.

We claim: 
     
         1 . A method for producing at least one fermentable sugar from a feedstock, comprising contacting the feedstock with an enzyme composition comprising a xylosidase enzyme having at least 90% identity to SEQ ID NO:8, under culture conditions whereby fermentable sugars are produced. 
     
     
         2 . The method of  claim 1 , wherein the enzyme composition further comprises at least one enzyme selected from endoglucanases (EG), β-glucosidases (BGL), Type 1 cellobiohydrolases (CBH1), Type 2 cellobiohydrolases (CBH2), and GH61 enzymes. 
     
     
         3 . The method of  claim 1 , wherein the feedstock comprises wheat grass, wheat straw, barley straw, sorghum, rice grass, sugarcane, sugar beet, bagasse, switchgrass, corn stover, corn fiber, grains, or a combination thereof. 
     
     
         4 . The method of  claim 1 , wherein the fermentable sugar comprises glucose and/or xylose. 
     
     
         5 . The method of  claim 1 , further comprising contacting the at least one fermentable sugar with a microorganism under conditions such that said microorganism produces at least one fermentation end product. 
     
     
         6 . The method of  claim 5 , wherein said fermentation end product is selected from alcohols, fatty acids, lactic acid, acetic acid, 3-hydroxypropionic acid, acrylic acid, succinic acid, citric acid, malic acid, fumaric acid, succinic acid, amino acids, 1,3-propanediol, ethylene, glycerol, and β-lactams. 
     
     
         7 . A method of producing an end product from a feedstock, comprising:
 a) contacting the feedstock with at least one enzyme composition comprising a xylosidase enzyme having at least 90% identity to SEQ ID NO:8, under conditions whereby at least one fermentable sugar is produced from the substrate; and   b) contacting the fermentable sugar with a microorganism under conditions such that the microorganism uses the fermentable sugar to produce an end-product.   
     
     
         8 . The method of  claim 7 , wherein the method comprises simultaneous saccharification and fermentation reactions (SSF) or wherein said method comprises separate saccharification and fermentation reactions (SHF). 
     
     
         9 . The method of  claim 7 , wherein the enzyme composition further comprises at least one enzyme selected from endoglucanases (EG), β-glucosidases (BGL), Type 1 cellobiohydrolases (CBH1), Type 2 cellobiohydrolases (CBH2), and/or GH61 enzymes. 
     
     
         10 . The method of  claim 7 , wherein the feedstock comprises wheat grass, wheat straw, barley straw, sorghum, rice grass, sugarcane, sugar beet, bagasse, switchgrass, corn stover, corn fiber, grains, or a combination thereof. 
     
     
         11 . The method of  claim 7 , further comprising recovering at least one fermentable sugar. 
     
     
         12 . The method of  claim 7 , further comprising the step of contacting the at least one fermentable sugar with a microorganism under conditions such that said microorganism produces at least one fermentation end product. 
     
     
         13 . The method of  claim 12 , wherein said fermentation end product is selected from alcohols, fatty acids, lactic acid, acetic acid, 3-hydroxypropionic acid, acrylic acid, succinic acid, citric acid, malic acid, fumaric acid, succinic acid, amino acids, 1,3-propanediol, ethylene, glycerol, and β-lactams.