Enhancing Fermentation of Starch- And Sugar-Based Feedstocks

Abstract

Provided are methods, systems, and compositions for increasing the rate and/or yield of fermentation processes using blended feedstocks. Also provided are methods, systems, and compositions for decreasing the yield of one or more undesirable products during fermentation.

1 .- 30 . (canceled) 
     
     
         31 . A system for producing one or more fermentation end-produces, the system comprising:
 (a) a fermentor;   (b) a blended feedstock comprising:
 (i) a liquid biomass composition comprising non-cellulosic saccharides; and 
 (ii) a C6-enriched cellulosic hydrolyzate comprising from about 10% to about 70% (w/v) C6 monosaccharides, wherein less than about 20% (w/w) of saccharides in the C6-enriched cellulosic hydrolyzate are C5 saccharides; 
   (c) one or more enzymes that hydrolyze starch; and   (d) one or more fermenting microorganisms.   
     
     
         32 . The system of  claim 31 , wherein the liquid biomass composition comprises the non-cellulosic saccharides at a monosaccharides equivalent concentration that differs from the C6-enriched cellulosic hydrolyzate by less than 50%. 
     
     
         33 . The system of  claim 31 , wherein the liquid biomass composition and the C6-enriched cellulosic hydrolyzate are present in the blended feedstock at from about a 50:50 to about a 99:1 (v/v) ratio. 
     
     
         34 . The system of  claim 31 , wherein the liquid biomass composition and the C6-enriched cellulosic hydrolyzate are present in the blended feedstock at from about a 80:20 to about a 90:10 (v/v) ratio. 
     
     
         35 . The system of  claim 31 , wherein less than about 10% (w/w) of saccharides in the C6-enriched cellulosic hydrolyzate are C5 saccharides. 
     
     
         36 . The system of  claim 31 , wherein the C6-enriched cellulosic hydrolyzate comprises one or more inhibitory compounds at less than about 1% w/v. 
     
     
         37 . The system of  claim 36 , wherein the one or more inhibitory compounds comprise acetic acid, lactic acid, formic acid, hydroxymethylfurfural, furfural, low molecular weight lignin, or a combination thereof. 
     
     
         38 . The system of  claim 31 , wherein the one or more fermenting microorganisms comprise a C6 fermenting microorganisms. 
     
     
         39 . The system of  claim 31 , wherein the one or more fermenting microorganisms comprise one or more yeast strains. 
     
     
         40 . The system of  claim 31 , wherein the one or more fermentation end-products comprise ethanol. 
     
     
         41 . The system of  claim 31 , wherein the system produces the one or more fermentation end-products at a rate that is faster than a system without the C6-enriched cellulosic hydrolyzate. 
     
     
         42 . The system of  claim 31 , wherein the system produces a yield of the one or more fermentation end-products that is higher than a system without the C6-enriched cellulosic hydrolyzate. 
     
     
         43 . The system of  claim 31 , wherein one or more enzymes that hydrolyze starch are selected from the list consisting of alpha-amylase, glucoamylase, beta-amylase, exo-alpha-1,4-glucanase, pullulanase, and combinations thereof. 
     
     
         44 . A method for producing one or more fermentation end-produces, the method comprising:
 (a) combining a liquid biomass composition comprising non-cellulosic saccharides and a C6-enriched cellulosic hydrolyzate comprising from about 10% to about 70% (w/v) C6 monosaccharides to produce a blended feedstock, wherein less than about 20% (w/w) of saccharides in the C6-enriched cellulosic hydrolyzate are C5 saccharides;   (b) contacting the liquid biomass composition with one or more enzymes that hydrolyze starch; and   (c) contacting the blended feedstock with one or more fermenting microorganisms for a time sufficient to produce the one or more fermentation end-products.   
     
     
         45 . The method of  claim 44 , wherein the liquid biomass composition comprises the non-cellulosic saccharides at a monosaccharides equivalent concentration that differs from the C6-enriched cellulosic hydrolyzate by less than 50%. 
     
     
         46 . The method of  claim 44 , wherein the liquid biomass composition and the C6-enriched cellulosic hydrolyzate are present in the blended feedstock at from about a 50:50 to about a 99:1 (v/v) ratio. 
     
     
         47 . The method of  claim 44 , wherein the liquid biomass composition and the C6-enriched cellulosic hydrolyzate are present in the blended feedstock at from about a 80:20 to about a 90:10 (v/v) ratio. 
     
     
         48 . The method of  claim 44 , wherein less than about 10% (w/w) of saccharides in the C6-enriched cellulosic hydrolyzate are C5 saccharides. 
     
     
         49 . The method of  claim 44 , wherein the C6-enriched cellulosic hydrolyzate comprises one or more inhibitory compounds at less than about 1% w/v. 
     
     
         50 . The method of  claim 49 , wherein the one or more inhibitory compounds comprise acetic acid, lactic acid, formic acid, hydroxymethylfurfural, furfural, low molecular weight lignin, or a combination thereof. 
     
     
         51 . The method of  claim 44 , wherein the one or more fermenting microorganisms comprise a C6 fermenting microorganisms. 
     
     
         52 . The method of  claim 44 , wherein the one or more fermenting microorganisms comprise one or more yeast strains. 
     
     
         53 . The method of  claim 44 , wherein the one or more fermentation end-products comprise ethanol. 
     
     
         54 . The method of  claim 44 , wherein the system produces the one or more fermentation end-products at a rate that is faster than a system without the C6-enriched cellulosic hydrolyzate. 
     
     
         55 . The method of  claim 44 , wherein the system produces a yield of the one or more fermentation end-products that is higher than a system without the C6-enriched cellulosic hydrolyzate. 
     
     
         56 . The method of  claim 44 , wherein one or more enzymes that hydrolyze starch are selected from the list consisting of alpha-amylase, glucoamylase, beta-amylase, exo-alpha-1,4-glucanase, pullulanase, and combinations thereof.