Synthesis of long-chain polyunsaturated fatty acids by recombinant cell

Abstract

The present invention relates to methods of synthesizing long-chain polyunsaturated fatty acids, especially eicosapentaenoic acid, docosapentaenoic acid and docosahexaenoic acid, in recombinant cells such as yeast or plant cells. Also provided are recombinant cells or plants which produce long-chain polyunsaturated fatty acids. Furthermore, the present invention relates to a group of new enzymes which possess desatorase or elongase activity that can be used in methods of synthesizing long-chain polyunsaturated fatty acids.

1 - 221 . (canceled) 
     
     
         222 . A process for producing oil comprising docosahexanoic acid (DHA), comprising extracting oil from a recombinant cell which is capable of synthesizing DHA, and which comprises one or more polynucleotides which encode:
 a) a Δ5/Δ6 bifunctional desaturase, a Δ5/Δ6 bifunctional elongase, and a Δ4 desaturase,   b) a Δ5/Δ6 bifunctional desaturase, a Δ5 elongase, a Δ6 elongase, and a Δ4 desaturase, or   c) a Δ5 desaturase, a Δ6 desaturase, a Δ5/Δ6 bifunctional elongase, and a Δ4 desaturase.   
     
     
         223 . The process of  claim 222 , wherein the recombinant cell is a recombinant  Arabidopsis thaliana  or  Brassica napus  cell. 
     
     
         224 . The process of  claim 222 , wherein the recombinant cell comprises one or more polynucleotides which encode a Δ5 desaturase, a Δ6 desaturase, a Δ5/Δ6 bifunctional elongase, and a Δ4 desaturase. 
     
     
         225 . The process of  claim 224 , wherein the Δ5/Δ6 bifunctional elongase comprises an amino acid sequence as provided in SEQ ID NO:2 or SEQ ID NO:14. 
     
     
         226 . The process of  claim 222 , wherein the recombinant cell comprises one or more polynucleotides which encode:
 a) a Δ5/Δ6 bifunctional desaturase, a Δ5/Δ6 bifunctional elongase, and a Δ4 desaturase, or   b) a Δ5/Δ6 bifunctional desaturase, a Δ5 elongase, a Δ6 elongase, and a Δ4 desaturase.   
     
     
         227 . The process of  claim 226 , wherein the Δ5/Δ6 bifunctional desaturase comprises an amino acid sequence as provided in SEQ ID NO:15. 
     
     
         228 . The process of  claim 222 , wherein the recombinant cell comprises at least one C20 LC-PUFA which is synthesized in the cell, and wherein the total fatty acid of the cell comprises at least 2%, at least 4.7%, or at least 7.9% C20 LC-PUFA. 
     
     
         229 . The process of  claim 222 , wherein the recombinant cell comprises at least one C20 LC-PUFA which is synthesized in the cell, and wherein the total fatty acid of the cell comprises between 2% and 10.2% C20 LC-PUFA. 
     
     
         230 . The process of  claim 222 , wherein the recombinant cell comprises at least one ω3 C20 LC-PUFA which is synthesized in the cell and wherein the total fatty acid of the cell comprises at least 2.5%, or at least 4.1% C20 LC-PUFA. 
     
     
         231 . The process of  claim 222 , wherein the recombinant cell comprises at least one ω3 C20 LC-PUFA which is synthesized in the cell and wherein the total fatty acid of the cell comprises between 2.5% and 5.0% ω3 C20 LC-PUFA. 
     
     
         232 . The process of  claim 222 , wherein the recombinant cell comprises ω3 polyunsaturated fatty acids that are the products of Δ6-desaturation of α-linoleic acid (ALA), which products are synthesized in the cell, and wherein the efficiency of conversion of ALA to said products in the cells is at least 22% or at least 24%. 
     
     
         233 . A method of treating or preventing a condition which would benefit from a LC-PUFA, the method comprising administering to a subject oil comprising docosahexanoic acid (DHA) produced according to the method of  claim 222 .