Glycolic acid production by fermentation from renewable resources
First Claim
1. A method for the fermentative production of glycolic acid (glycolate), the method comprising:
- culturing a strain of Escherichia coli (E. coli) in an appropriate culture medium comprising a fermentable source of carbon, the culturing comprising;
a) fermenting the strain of E. coli to produce glycolic acid by converting the fermentable source of carbon into glycolic acid,b) concentrating the glycolic acid in the strain of E. coli or in the medium, andc) recovering the glycolic acid from the culture medium;
wherein the fermentable source of carbon is glucose; and
wherein the strain of E. coli comprises;
a modification that attenuates the expression of at least one gene selected from the group consisting of;
aceB encoding malate synthase,glcB encoding the second malate synthase, andgcl encoding glyoxylate carboligase; and
a modification that increases the expression of a ycdW or a yiaE gene encoding a polypeptide with NADPH dependent glyoxylate reductase activity that catalyzes the conversion of glyoxylate to glycolate.
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Abstract
The present invention provides a method for the biological production of glycolic acid from a fermentable carbon source in a microorganism. In one aspect of the present invention, a process for the conversion of glucose to glycolic acid is achieved by the use of a recombinant organism comprising a host E. coli transformed i) to attenuate the glyoxylate consuming pathways to other compounds than glycolate ii) to use an NADPH glyoxylate reductase to convert glyoxylate to glycolate iii) to attenuate the level of all the glycolate metabolizing enzymes and iv) increase the flux in the glyoxylate pathway. In another aspect of the present invention, the process for the production of glycolic acid from a fermentable carbon source, using a recombinant E. coli, is improved by increasing the NADPH availability in the cells. Optionally the glycolic acid produced can be purified through a step of polymerization to at least glycolic acid dimers and recovered by depolymerization from glycolic acid dimers, oligomers and/or polymers.
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Citations
33 Claims
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1. A method for the fermentative production of glycolic acid (glycolate), the method comprising:
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culturing a strain of Escherichia coli (E. coli) in an appropriate culture medium comprising a fermentable source of carbon, the culturing comprising; a) fermenting the strain of E. coli to produce glycolic acid by converting the fermentable source of carbon into glycolic acid, b) concentrating the glycolic acid in the strain of E. coli or in the medium, and c) recovering the glycolic acid from the culture medium; wherein the fermentable source of carbon is glucose; and wherein the strain of E. coli comprises; a modification that attenuates the expression of at least one gene selected from the group consisting of; aceB encoding malate synthase, glcB encoding the second malate synthase, and gcl encoding glyoxylate carboligase; and a modification that increases the expression of a ycdW or a yiaE gene encoding a polypeptide with NADPH dependent glyoxylate reductase activity that catalyzes the conversion of glyoxylate to glycolate. - View Dependent Claims (2, 3, 4, 5, 6, 7, 8, 9, 10, 11, 12, 13, 14, 15, 16, 17, 18, 19, 20, 21, 22, 23, 24, 25, 26, 27, 28, 29, 30, 31, 32, 33)
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Specification