Microbial production of n-butyraldehyde

Abstract

Microorganisms and methods of producing n-butyraldehyde with enhanced yields are presented in which a microorganism is engineered to enhance the conversion of a carbon source into n-butyraldehyde. The n-butyraldehyde is recovered by way of a gas stripping process that occurs during the conversion process, providing significantly greater product yield than post-fermentation recovery of n-butyraldehyde alone.

What is claimed is: 
     
         1 . A genetically modified microorganism for producing n-butyraldehyde, comprising:
 (a) a recombinant nucleic acid comprising at least one expressible heterologous gene selected from the group consisting of an acetyl-CoA acetyltransferase, a 3-hydroxyacyl-CoA dehydrogenase, a crotonyl-CoA hydratase, a butyryl-CoA dehydrogenase, a trans-enoyl-CoA reductase, and a butanal dehydrogenase; or   (b) a recombinant nucleic acid comprising an artificial operon to allow for expression of atoB, crt, hbd, and bldh; and   
       wherein at least one native gene is deleted to reduce alcohol production by at least 50%; and 
       wherein the at least one heterologous gene or operon is expressed in an amount to allow for conversion of a carbon source into n-butyraldehyde. 
     
     
         2 . The microorganism of  claim 1 , wherein the acetyl-CoA acetyltransferase has an E.C. number of 2.3.1.9. 
     
     
         3 . The microorganism of  claim 1 , wherein the 3-hydroxyacyl-CoA dehydrogenase has an E.C. number of 1.1.1.157. 
     
     
         4 . The microorganism of  claim 1 , wherein the crotonyl-CoA hydratase has an E.C. number of 4.2.1.55. 
     
     
         5 . The microorganism of  claim 1 , wherein the butyryl-CoA dehydrogenase has an E.C. number of 1.3.99.2. 
     
     
         6 . The microorganism of  claim 1 , wherein the trans-enoyl-CoA reductase has an E.C. number of 1.3.1.38. 
     
     
         7 . The microorganism of  claim 1 , wherein the butanal dehydrogenase has an E.C. number of 1.2.1.57. 
     
     
         8 . The microorganism of  claim 1 , wherein the at least one native gene is selected from the group consisting of ldhA, adhE, frdBC, pta, and yqhD. 
     
     
         9 . The microorganism of  claim 1 , wherein the at least one native gene are ldhA, adhE, and frdBC. 
     
     
         10 . The microorganism of  claim 1 , wherein the at least one native gene are ldhA, adhE, frdBC, pta, and yqhD. 
     
     
         11 . The microorganism of  claim 1 , wherein at least one native gene is deleted to reduce alcohol production by at least 70%. 
     
     
         12 . The microorganism of  claim 1 , wherein at least one native gene is deleted to reduce alcohol production by at least 90%. 
     
     
         13 . The microorganism of  claim 1 , wherein the genetically modified microorganism produces a cumulative yield of 2.0 g/L n-butyraldehyde at or before 40 hours of culture time. 
     
     
         14 . The microorganism of  claim 1 , wherein the genetically modified microorganism produces 50% of a maximum cumulative yield at or before 24 hours culture time. 
     
     
         15 . The microorganism of  claim 1  wherein the microorganism belongs to a genus selected from the group consisting of  Escherichia, Corynebacterium, Clostridium, Zymonomas, Salmonella, Rhodococcus, Pseudomonas, Bacillus, Lactobacillus, Enterococcus, Alcaligenes, Klebsiella, Paenibacillus, Arthrobacter, Brevibacterium, Pichia, Candida, Hansenula, Synechococcus, Synechocystis, Anabaena, Ralstonia, Lactococcus  and  Saccharomyces.    
     
     
         16 . The microorganism of  claim 1 , wherein the microorganism is  E. coli.    
     
     
         17 . The microorganism of  claim 1 , wherein the carbon source is selected form the group consisting of a protein, a carbohydrate, a lipid, a cell extract, biomass, biosolids, or any mixture thereof. 
     
     
         18 . The microorganism of  claim 1 , wherein the at least one native gene is pta. 
     
     
         19 . The microorganism of  claim 1 , wherein the recombinant nucleic acid comprises an artificial operon to allow for expression of atoB, crt, hbd, and bldh. 
     
     
         20 . The microorganism of  claim 1 , wherein the recombinant nucleic acid comprises at least one expressible heterologous gene selected from the group consisting of a crotonyl-CoA hydratase, a trans-enoyl-CoA reductase, and a butanal dehydrogenase.