Production and Purification of Esters of Polyunsaturated Fatty Acids

Abstract

The present invention includes methods for producing and purifying esters of polyunsaturated fatty acids that include reacting a composition having triglycerides with polyunsaturated fatty acid residues in the presence of an alcohol and a base to produce an ester of a polyunsaturated fatty acid from the triglycerides. The composition can be a polyunsaturated fatty acid-containing composition that has not been conventionally processed. The reacted composition can be further processed by distillation.

1 . A method for purifying a composition comprising triglycerides having polyunsaturated fatty acid residues comprising:
 a) reacting the composition in the presence of an alcohol and a base to produce an ester of a polyunsaturated fatty acid from the triglycerides; and   b) distilling the composition to recover a fraction comprising the ester of the polyunsaturated fatty acid.   
   
   
       2 . The method of  claim 1 , wherein the step of reacting the composition in the presence of an alcohol and a base is performed at a temperature from about 60° C. to about 120° C. 
   
   
       3 . The method of  claim 1 , wherein the step of reacting the composition in the presence of an alcohol and a base is performed for a time from about 2 hours to about 12 hours. 
   
   
       4 . The method of  claim 1 , wherein the composition comprising triglycerides having polyunsaturated fatty acid residues has not been subjected to one or more treatments selected from the group consisting of refining, desolventization, deodorization, winterization, chill filtration, and bleaching. 
   
   
       5 . The method of  claim 1 , wherein the composition comprising triglycerides having polyunsaturated fatty acid residues has not been subjected to refining, desolventization, deodorization, winterization, chill filtration, and bleaching. 
   
   
       6 . The method of  claim 1 , wherein the composition comprising triglycerides having polyunsaturated fatty acid residues is from a source selected from the group consisting of a plant, a microorganism, an animal, and mixtures of the foregoing. 
   
   
       7 . The method of  claim 6 , wherein the source is a microorganism selected from the group consisting of algae, bacteria, fungi and protists. 
   
   
       8 . The method of  claim 6 , wherein the source is selected from the group consisting of plants selected from the group consisting of soybean, corn, rice, safflower, sunflower, canola, flax, peanut, mustard, rapeseed, chickpea, cotton, lentil, white clover, olive, palm, borage, evening primrose, linseed and tobacco and mixtures thereof. 
   
   
       9 . The method of  claim 6 , wherein the source is selected from the group consisting of a genetically modified plant and a genetically modified microorganism, wherein the genetic modification comprises the introduction of polyketide synthase genes. 
   
   
       10 . The method of  claim 6 , wherein the source is a microorganism selected from the group consisting of Thraustochytriales, dinoflagellates, and  Mortierella.    
   
   
       11 . The method of  claim 10 , wherein the microorganism is Thraustochytriales. 
   
   
       12 . The method of  claim 11 , wherein the microorganism is  Schizochytrium.    
   
   
       13 . The method of  claim 11 , wherein the microorganism is  Thraustochytrium.    
   
   
       14 . The method of  claim 10 , wherein the microorganism is a dinoflagellate of the genus  Crypthecodinium.    
   
   
       15 . The method of  claim 6 , wherein the source is an animal selected from aquatic animals. 
   
   
       16 . The method of  claim 1 , wherein the polyunsaturated fatty acid is a polyunsaturated fatty acid having a chain length of at least 18 carbons. 
   
   
       17 . The method of  claim 1 , wherein the polyunsaturated fatty acid is a polyunsaturated fatty acid selected from the group consisting of docosahexaenoic acid, docosapentaenoic acid, arachidonic acid, eicosapentaenoic acid, stearidonic acid, linolenic acid, alpha linolenic acid, gamma linolenic acid, conjugated linolenic acid and mixtures thereof. 
   
   
       18 . The method of  claim 17 , wherein the polyunsaturated fatty acid is docosahexaenoic acid. 
   
   
       19 . The method of  claim 17 , wherein the polyunsaturated fatty acid is arachadonic acid. 
   
   
       20 . The method of  claim 1 , wherein the base is a base of the formula RO-M, wherein M is a monovalent cation and RO is an alkoxide of a C 1-6  alkyl alcohol. 
   
   
       21 . The method of  claim 1 , wherein the base is sodium ethoxide. 
   
   
       22 . The method of  claim 1 , wherein the alcohol is a C 1-6  alkyl alcohol. 
   
   
       23 . The method of  claim 1 , wherein the alcohol is ethanol and the ester is an ethyl ester of the polyunsaturated fatty acid. 
   
   
       24 . The method of  claim 1 , wherein the step of distilling the composition to recover a fraction comprising the ester of the polyunsaturated fatty acid is performed under vacuum. 
   
   
       25 . The method of  claim 24 , wherein the step of distilling the composition to recover a fraction comprising the ester of the polyunsaturated fatty acid is performed at a temperature of less than about 170° C. 
   
   
       26 . The method of  claim 1 , wherein the fraction recovered comprises at least about 50 wt. % ester of the polyunsaturated fatty acid. 
   
   
       27 . The method of  claim 1 , wherein the fraction recovered comprises at least about 75 wt. % ester of the polyunsaturated fatty acid. 
   
   
       28 . The method of  claim 1 , wherein the fraction recovered comprises at least about 90 wt. % ester of the polyunsaturated fatty acid. 
   
   
       29 . The method of  claim 1 , wherein the fraction recovered comprises at least about 95 wt. % ester of the polyunsaturated fatty acid. 
   
   
       30 . The method of  claim 1 , wherein the step of reacting the composition in the presence of an alcohol and a base produces an ester of a polyunsaturated fatty acid from the triglycerides by direct transesterification. 
   
   
       31 . The method of  claim 1 , further comprising:
 a) combining the fraction comprising the ester of the polyunsaturated fatty acid with urea in a medium;   b) cooling or concentrating the medium to form a urea-containing precipitate and a liquid fraction; and   c) separating the precipitate from the liquid fraction.   
   
   
       32 . The method of  claim 31 , wherein the medium further comprises an organic solvent that can solubilize the ester of the polyunsaturated fatty acid. 
   
   
       33 . The method of  claim 32 , wherein the organic solvent comprises an alkyl alcohol comprising from 1 to 4 carbon atoms. 
   
   
       34 . The method of  claim 33 , wherein the organic solvent comprises ethanol. 
   
   
       35 . The method of  claim 31 , wherein the medium is cooled to a temperature of from about 0° C. to about 25° C. to form the urea-containing precipitate. 
   
   
       36 . The method of  claim 31 , wherein at least a portion of the urea-containing precipitate is formed under a non-oxidizing atmosphere. 
   
   
       37 . A method for producing an ester of a polyunsaturated fatty acid from a composition comprising triglycerides having polyunsaturated fatty acid residues comprising:
 a) transesterifying the composition in the presence of an alcohol and a base to produce an ester of the polyunsaturated fatty acid from the triglycerides; and   b) distilling the composition to recover a fraction comprising the ester of the polyunsaturated fatty acid.   
   
   
       38 . (canceled) 
   
   
       39 . A method for preparing a composition comprising an ester of a polyunsaturated fatty acid comprising:
 reacting a composition comprising triglycerides having polyunsaturated fatty acid residues in the presence of an alcohol and a base to produce an ester of a polyunsaturated fatty acid from the triglycerides,   wherein the composition comprising triglycerides having polyunsaturated fatty acid residues has not been subjected to one or more treatments selected from the group consisting of refining, desolventization, deodorization, winterization, chill filtration, and bleaching.   
   
   
       40 - 67 . (canceled) 
   
   
       68 . A composition comprising at least about 90 wt. % ethyl ester of docosahexaenoic acid, wherein the composition further comprises at least about 0.1 wt. % of 4,7,10,13,16,19,22,25 octacosaoctaenoic acid (C28:8) or an ester thereof. 
   
   
       69 . The composition of  claim 68 , wherein the composition comprises at least about 0.5 wt. % of 4,7,10,13,16,19,22,25 octacosaoctaenoic acid (C28:8) or an ester thereof. 
   
   
       70 . The composition of  claim 68 , wherein the composition comprises at least about 1.0 wt. % of 4,7,10,13,16,19,22,25 octacosaoctaenoic acid (C28:8) or an ester thereof. 
   
   
       71 . The composition of  claim 68 , wherein the composition comprises at least about 1.2 wt. % of 4,7,10,13,16,19,22,25 octacosaoctaenoic acid (C28:8) or an ester thereof. 
   
   
       72 . The composition of  claim 68 , wherein the composition further comprises at least about 0.1 wt. % of docosapentaenoic acid (n-3) or an ester thereof. 
   
   
       73 . The composition of  claim 68 , wherein the composition further comprises at least about 0.3 wt. % of docosapentaenoic acid (n-3) or an ester thereof. 
   
   
       74 . The composition of  claim 68 , wherein the composition further comprises at least about 0.4 wt. % of docosapentaenoic acid (n-3) or an ester thereof. 
   
   
       75 . The composition of  claim 68 , wherein the composition further comprises at least about 0.5 wt. % of docosapentaenoic acid (n-3) or an ester thereof. 
   
   
       76 . The composition of  claim 68 , wherein the composition comprises at least about 92 wt. % ethyl ester of docosahexaenoic acid. 
   
   
       77 . The composition of  claim 68 , wherein the composition comprises at least about 95 wt. % ethyl ester of docosahexaenoic acid. 
   
   
       78 . The composition of  claim 68 , wherein the composition further comprises less than about 1 wt. % eicosapentaenoic acid or an ester thereof. 
   
   
       79 . The composition of  claim 68 , wherein the composition further comprises less than about 0.5 wt. % eicosapentaenoic acid or an ester thereof. 
   
   
       80 . The composition of  claim 68 , wherein the composition further comprises less than about 0.25 wt. % eicosapentaenoic acid or an ester thereof. 
   
   
       81 . A composition comprising at least about 90 wt. % ethyl ester of docosahexaenoic acid, wherein the composition further comprises at least about 0.1 wt. % of docosapentaenoic acid (n-3) or an ester thereof. 
   
   
       82 . The composition of  claim 81 , wherein the composition comprises at least about 0.3 wt. % of docosapentaenoic acid (n-3) or an ester thereof. 
   
   
       83 . The composition of  claim 81 , wherein the composition comprises at least about 0.4 wt. % of docosapentaenoic acid (n-3) or an ester thereof. 
   
   
       84 . The composition of  claim 81 , wherein the composition comprises at least about 0.5 wt. % of docosapentaenoic acid (n-3) or an ester thereof. 
   
   
       85 . The composition of  claim 81 , wherein the composition further comprises at least about 0.5 wt. % of 4,7,10,13,16,19,22,25 octacosaoctaenoic acid (C28:8) or an ester thereof. 
   
   
       86 . The composition of  claim 81 , wherein the composition further comprises at least about 0.75 wt. % of 4,7,10,13,16,19,22,25 octacosaoctaenoic acid (C28:8) or an ester thereof. 
   
   
       87 . The composition of  claim 81 , wherein the composition further comprises at least about 1.0 wt. % of 4,7,10,13,16,19,22,25 octacosaoctaenoic acid (C28:8) or an ester thereof. 
   
   
       88 . The composition of  claim 81 , wherein the composition further comprises at least about 1.2 wt. % of 4,7,10,13,16,19,22,25 octacosaoctaenoic acid (C28:8) or an ester thereof. 
   
   
       89 . The composition of  claim 81 , wherein the composition comprises at least about 92 wt. % ethyl ester of docosahexaenoic acid. 
   
   
       90 . The composition of  claim 81 , wherein the composition comprises at least about 95 wt. % ethyl ester of docosahexaenoic acid. 
   
   
       91 . The composition of  claim 81 , wherein the composition further comprises less than about 1 wt. % eicosapentaenoic acid or an ester thereof. 
   
   
       92 . The composition of  claim 81 , wherein the composition further comprises less than about 0.5 wt. % eicosapentaenoic acid or an ester thereof. 
   
   
       93 . The composition of  claim 81 , wherein the composition further comprises less than about 0.25 wt. % eicosapentaenoic acid or an ester thereof. 
   
   
       94 . A composition comprising at least about 90 wt. % ethyl ester of docosahexaenoic acid, wherein the composition further comprises at least one additional fatty acid or an ester thereof with a boiling point of about 150-170° C. at a pressure of 0.8 mm Hg. 
   
   
       95 - 98 . (canceled) 
   
   
       99 . A composition comprising at least about 90 wt. % of a combination of ethyl ester of docosahexaenoic acid and ethyl ester of docosapentaenoic acid (n-6). 
   
   
       100 - 109 . (canceled) 
   
   
       110 . A method of treating a subject with high levels of triglycerides comprising administering a composition according to  claim 68 ,  81 ,  94 , or  99  to the subject. 
   
   
       111 . A method of treating a subject with a neurological disorder, dementia or a pre-dementia related condition comprising administering a composition according to  claim 68 ,  81 ,  94 , or  99  to the subject.