Biosynthesis of 1-Alkenes in Engineered Microorganisms

Abstract

Various 1-alkenes, including 1-nonadecene and 1-octadecene, are synthesized by the engineered microorganisms and methods of the invention. In certain embodiments, the microorganisms comprise recombinant 1-alkene synthases. The engineered microorganisms may be photosynthetic microorganisms such as cyanobacteria.

What is claimed is: 
     
         1 . A method for the biosynthetic production of 1-alkenes, comprising:
 culturing an engineered microorganism in a culture medium, wherein said engineered microorganism comprises a recombinant 1-alkene synthase, wherein said 1-alkene synthase is at least 95% identical to SEQ ID NO: 2, and wherein the amount of said 1-alkenes produced by said engineered microorganism is greater than the amount that would be produced by an otherwise identical microorganism, cultured under identical conditions, but lacking said recombinant 1-alkene synthase.   
     
     
         2 . The method of  claim 1 , wherein said recombinant 1-alkene synthase is an endogenous 1-alkene synthase expressed, at least in part, from a promoter other than its native promoter. 
     
     
         3 . The method of  claim 1 , wherein said recombinant 1-alkene synthase is a heterologous 1-alkene synthase. 
     
     
         4 . The method of  claim 1 , wherein said recombinant 1-alkene synthase is expressed from a heterologous promoter. 
     
     
         5 . The method of  claim 4 , wherein said 1-alkene synthase is endogenous to said microorganism. 
     
     
         6 . The method of  claim 1 , wherein said engineered microorganism is a photosynthetic microorganism, and wherein exposing said engineered microorganism to light and carbon dioxide results in the production of alkenes by said microorganism. 
     
     
         7 . The method of  claim 6 , wherein said engineered microorganism is a  cyanobacterium.    
     
     
         8 . The method of  claim 1  or  6 , wherein said 1-alkenes are selected from the group consisting of 1-nonadecene and 1-octadecene. 
     
     
         9 . The method of  claim 1  or  6 , further comprising isolating said 1-alkenes from said  cyanobacterium  or said culture medium. 
     
     
         10 . A method for the biosynthetic production of an olefin, comprising
 (1) culturing a  cyanobacterium  in a culture medium, wherein said  cyanobacterium  comprises a 1-alkene synthase activity, wherein said 1-alkene synthase is at least 95% identical to SEQ ID NO: 2, and wherein said culture medium comprises an exogenous fatty acid;   (2) exposing said engineered  cyanobacterium  to light and carbon dioxide, wherein said exposure results in the production of an olefin by said  cyanobacterium , and wherein the amount of said olefin produced is greater than the amount that would be produced by an otherwise identical  cyanobacterium , cultured under identical conditions but in the absence of said exogenous fatty acid.   
     
     
         11 . The method of  claim 10 , wherein said concentration of said fatty acid in said culture medium is at least 1 μg/ml. 
     
     
         12 . The method of  claim 11 , wherein said fatty acid is an odd-chain fatty acid. 
     
     
         13 . The method of  claim 12 , wherein said odd-chain fatty acid is tridecanoic acid and said olefin is 1-octadecene. 
     
     
         14 . The method of  claim 13 , wherein the amount of said 1-octadecene produced is at least 0.039% dry cell weight. 
     
     
         15 . The method of  claim 10 , further comprising isolating said olefin from said  cyanobacterium  or said culture medium. 
     
     
         16 . A method for the biosynthetic production of alkenes, comprising
 (1) culturing an engineered microorganism in a culture medium, wherein said engineered microorganism comprises a modification, wherein said modification reduces the activity of a hydrolase having an amino acid sequence that has at least 95% sequence identity to SEQ ID NO:4; and   (2) exposing said engineered microorganism to light and carbon dioxide, wherein said exposure results in the production of alkenes by said engineered microogransims, wherein said alkenes comprise 1-alkenes, and wherein the amount of 1-alkenes produced is greater than the amount that would be produced by an otherwise identical microorganism, cultured under identical conditions, but lacking said modification.   
     
     
         17 . The method of  claim 16 , wherein said 1-alkenes include 1-nonadecene. 
     
     
         18 . The method of  claim 16 , wherein said microorganism is a cyanobacteria.