PRODUCTION OF FATTY ACID ESTERS
Methods of producing fatty acid esters, such as fatty acid ethyl esters, from genetically engineered microorganisms are described.
1 . A method of producing a fatty acid ester, the method comprising culturing a genetically engineered microorganism in the absence of exogenous alcohol, wherein the microorganism is genetically engineered to produce an alcohol, a fatty acid, and at least one ester synthase.
2 . The method of claim 1 , further comprising the step of isolating the fatty acid ester.
3 . The method of claim 1 , wherein the microorganism is cultured in a culture medium comprising an initial concentration of about 2 g/L to about 50 g/L of glucose.
4 . The method of claim 1 , wherein the alcohol is ethanol.
5 . The method of claim 4 , wherein the fatty acid ester is a fatty acid ethyl ester.
6 . The method of claim 4 , wherein the microorganism is genetically engineered to overexpress at least one gene selected from the group consisting of pdc, adh, adhA, adhB, pdh, and casAB, relative to a corresponding wild type microorganism.
7 . The method of claim 4 , wherein the microorganism is genetically engineered to have reduced expression of at least one gene selected from the group consisting of frd, ldhA, pflA, pflB, adhE, ackA, and focA, relative to a corresponding wild type organism.
8 . The method of claim 1 , wherein the microorganism is a recombinant Escherichia coli cell.
9 . A fatty acid ester produced by the method of claim 1 .
10 . The fatty acid ester of claim 9 , wherein the fatty acid ester is a fatty acid ethyl ester.
11 . A method of producing a fatty acid ethyl ester, the method comprising culturing a genetically engineered microorganism in the absence of exogenous alcohol, wherein the microorganism is genetically engineered to produce a fatty acid and at least one ester synthase.
12 . The method of claim 11 , wherein the microorganism is genetically engineered to produce ethanol.
13 . The method of claim 12 , wherein the microorganism is genetically engineered to overexpress of at least one gene selected from the group consisting of pdc, adh, adhA, adhB, pdh, and casAB, relative to a wild type microorganism.
14 . The method of claim 12 , wherein the microorganism is genetically engineered to have reduced expression of at least one gene selected from the group consisting of frd, ldhA, pflA, pflB, adhE, ackA, and focA, relative to a wild type microorganism.
15 . The method of claim 3 , wherein the fatty acid ester is produced at a yield of about 10% to about 95% by mass of carbon in the glucose in the fermentation medium.
16 . The method of claim 3 , wherein the fatty acid ethyl ester is produced at a yield of about 0.5 g to about 50 g per 100 g of glucose in the fermentation medium.
17 . A genetically engineered microorganism comprising one or more of:
(a) a fatty acid synthesis regulator gene, wherein the fatty acid synthesis regulator gene has reduced expression relative to a wild type microorganism;
(b) a pyruvate oxidase gene, wherein the pyruvate oxidase gene has reduced expression relative to a wild type microorganism; and
(c) a lactate dehydrogenase gene, wherein the lactate dehydrogenase gene has reduced expression relative to a wild type microorganism.