Fermentation process for producing itaconic acid under nitrogen free conditions
First Claim
1. A method for the production of itaconic acid, which method comprises fermenting a recombinant cell selected from a bacterial cell or a yeast cell capable of producing itaconic acid in a suitable fermentation medium, thereby to produce itaconic acid, wherein:
- (a) the recombinant cell;
(i) overexpresses cis-aconitate decarboxylase; and
(ii) overexpresses a part of the citric acid cycle and/or has reduced activity of a native metabolic route to acetate and/or lactate, wherein overexpression of a part of the citric acid cycle is overexpression of a citrate synthase and/or overexpression of an aconitase and wherein reduced activity of a native metabolic route to acetate is reduced activity of a phosphate acetyltransferase by deleting, disrupting or inactivating the pta gene in the recombinant cell and/or wherein reduced activity of a native metabolic route to lactate is reduced activity of a lactate dehydrogenase by deleting, disrupting or inactivating the ldhA gene in the recombinant cell; and
,(b) the fermentation is carried out under anaerobic conditions, wherein fermentation carried out under anaerobic conditions means a fermentation process run in the absence of oxygen or in which substantially no oxygen is consumed or a fermentation process run under oxygen limited, or micro-aerobical, conditions; and
(c) wherein glutamate production is repressed by carrying out the fermentation under nitrogen free conditions.
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Abstract
The present invention relates to a method for the production of itaconic acid, which method comprises fermenting a recombinant cell capable of producing itaconic acid in a suitable fermentation medium, thereby to produce itaconic acid, wherein: (a) the recombinant cell: (i) overexpresses cis-aconitate decarboxylase; and (ii) overexpresses a part of the citric acid cycle and/or has reduced activity of a native metabolic route to acetate and/or lactate; and, optionally, (b) the fermentation is carried out under anaerobic conditions.
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Citations
10 Claims
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1. A method for the production of itaconic acid, which method comprises fermenting a recombinant cell selected from a bacterial cell or a yeast cell capable of producing itaconic acid in a suitable fermentation medium, thereby to produce itaconic acid, wherein:
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(a) the recombinant cell;
(i) overexpresses cis-aconitate decarboxylase; and
(ii) overexpresses a part of the citric acid cycle and/or has reduced activity of a native metabolic route to acetate and/or lactate, wherein overexpression of a part of the citric acid cycle is overexpression of a citrate synthase and/or overexpression of an aconitase and wherein reduced activity of a native metabolic route to acetate is reduced activity of a phosphate acetyltransferase by deleting, disrupting or inactivating the pta gene in the recombinant cell and/or wherein reduced activity of a native metabolic route to lactate is reduced activity of a lactate dehydrogenase by deleting, disrupting or inactivating the ldhA gene in the recombinant cell; and
,(b) the fermentation is carried out under anaerobic conditions, wherein fermentation carried out under anaerobic conditions means a fermentation process run in the absence of oxygen or in which substantially no oxygen is consumed or a fermentation process run under oxygen limited, or micro-aerobical, conditions; and (c) wherein glutamate production is repressed by carrying out the fermentation under nitrogen free conditions. - View Dependent Claims (2, 3, 4, 5)
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6. A method for the production of itaconic acid, which method comprises fermenting a recombinant bacterial cell capable of producing itaconic acid in a suitable fermentation medium, thereby to produce itaconic acid, wherein:
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(a) the recombinant cell;
(i) overexpresses Aspergillus terreus cis-aconitate decarboxylase; and
(ii) overexpresses a part of the citric acid cycle and has reduced activity of a native metabolic route to acetate and lactate, wherein overexpression of a part of the citric acid cycle is overexpression of the gltA gene coding for citrate synthase and overexpression of the acnA gene coding for aconitase and wherein reduced activity of a native metabolic route to acetate is reduced activity of a phosphate acetyltransferase by deleting, disrupting or inactivating the pta gene in the recombinant cell and wherein reduced activity of a native metabolic route to lactate is reduced activity of a lactate dehydrogenase by deleting, disrupting or inactivating the ldhA gene in the recombinant cell; and
,(b) the fermentation is carried out under anaerobic conditions, wherein fermentation carried out under anaerobic conditions means a fermentation process run in the absence of oxygen or in which substantially no oxygen is consumed or a fermentation process run under oxygen limited, or micro-aerobical, conditions; and
,(c) wherein glutamate production is repressed by carrying out the fermentation under nitrogen free conditions. - View Dependent Claims (7, 8, 9, 10)
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Specification