Host Cells and Methods for Production of Isobutanol

Abstract

The invention relates to recombinant host cells having at least one integrated polynucleotide encoding a polypeptide that catalyzes a step in a pyruvate-utilizing biosynthetic pathway, e.g., pyruvate to acetolactate conversion. The invention also relates to methods of increasing the biosynthetic production of isobutanol, 2,3-butanediol, 2-butanol or 2-butanone using such host cells.

What is claimed is: 
     
         1 . A recombinant host cell comprising:
 (a) a polynucleotide encoding a polypeptide which catalyzes the substrate to product conversion of pyruvate to acetolactate wherein the polypeptide is an acetolactate synthase from  Bacillus subtilis, Klebsiella pneumonia, Lactococcus lactis, Staphylococcus aureus, Listeria monocytogenes, Streptococcus mutans, Streptococcus thermophiles, Vibrio angustum , or  Bacillus cereus;      (b) a polynucleotide encoding a polypeptide which catalyzes the substrate to product conversion of acetolactate to 2,3-dihydroxyisovalerate wherein the polypeptide is a ketol-acid reductoisomerase and the ketol-acid reductoisomerase has at least 95% identity to SEQ ID NO: 224;   (c) a polynucleotide encoding a polypeptide which catalyzes the substrate to product conversion of 2,3-dihydroxyisovalerate to α-ketoisovalerate wherein the polypeptide is a dihydroxyacid dehydratase from  Escherichia coli, Bacillus subtilis, Methanococcus maripaludis , or  Streptococcus mutans;      (d) a polynucleotide encoding a polypeptide which catalyzes the substrate to product conversion of α-ketoisovalerate to isobutyraldehyde wherein the polypeptide is a branched-chain α-keto acid decarboxylase and the branched-chain α-keto acid decarboxylase has at least 95% identity to SEQ ID NO: 48; and   (e) a polynucleotide encoding a polypeptide which catalyzes the substrate to product conversion isobutyraldehyde to isobutanol wherein the polypeptide is an alcohol dehydrogenase from  Achromobacter xylosoxidans  or  Beijerinkia indica,      wherein expression of pyruvate decarboxylase in the recombinant host cell is decreased or eliminated.   
     
     
         2 . The recombinant host cell of  claim 1 , wherein the acetolactate synthase has at least 95% identity to an amino acid sequence selected from SEQ ID NOs: 4 or 6. 
     
     
         3 . The recombinant host cell of  claim 1 , wherein the ketol-acid reductoisomerase has at least 97% identity to SEQ ID NO: 224. 
     
     
         4 . The recombinant host cell of  claim 1 , wherein the dihydroxyacid dehydratase has at least 95% identity to amino acid sequence of SEQ ID NO: 89. 
     
     
         5 . The recombinant host cell of  claim 1 , wherein the branched-chain α-keto acid decarboxylase has at least 97% identity to SEQ ID NO: 48. 
     
     
         6 . The recombinant host cell of  claim 1 , wherein the alcohol dehydrogenase has at least 95% identity to an amino acid sequence selected from SEQ ID NOs: 36 or 237. 
     
     
         7 . The recombinant host cell of  claim 1 , wherein the recombinant host cell comprises a deletion, mutation, and/or substitution in an endogenous polynucleotide encoding a polypeptide having pyruvate decarboxylase activity. 
     
     
         8 . The recombinant host cell of  claim 1 , wherein expression of glycerol-3-phosphate dehydrogenase in the recombinant host cell is decreased or eliminated compared to control host. 
     
     
         9 . The recombinant host cell of  claim 1 , wherein expression of Fra2 in the recombinant host cell is decreased or eliminated compared to control host. 
     
     
         10 . The recombinant host cell of  claim 1 , wherein expression of glycerol-3-phosphate dehydrogenase and Fra2 in the recombinant host cell is decreased or eliminated compared to control host. 
     
     
         11 . The recombinant host cell of  claim 1 , wherein the recombinant host cell is selected from bacterium, cyanobacterium, filamentous fungus, or yeast. 
     
     
         12 . The recombinant host cell of  claim 1 , wherein the recombinant host cell is selected from the group consisting of  Clostridium, Zymomonas, Escherichia, Salmonella, Rhodococcus, Pseudomonas, Bacillus, Lactobacillus, Enterococcus, Alcaligenes, Klebsiella, Paenibacillus, Arthrobacter, Corynebacterium, Brevibacterium, Pichia, Candida, Hansenula, Issatchenkia, Kluyveromyces , and  Saccharomyces.    
     
     
         13 . The recombinant host cell of  claim 1 , wherein the recombinant host cell is selected from the group consisting of  Saccharomyces cerevisiae, Schizosaccharomyces pombe, Kluyveromyces lactis, Kluyveromyces thermotolerans, Candida glabrata, Candida albicans, Pichia stipitis , and  Yarrowia lipolytica.    
     
     
         14 . A method comprising
 (a) providing the recombinant host cell of  claim 1 ; and   (b) contacting the recombinant host cell with a fermentable carbon substrate under conditions whereby a product is produced.   
     
     
         15 . The method of  claim 14 , wherein the product is isobutanol.