Lactic acid processing; methods; arrangements; and, product
AssigneeCargill, Incorporated
InventorsAharon M. Eyal, John N. Starr, Rod Fisher, Betty Hazan, Riki Canari, David R. Witzke, Patrick R. Gruber, Jeffrey J. Kolstad
Life of this patent
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Abstract
The techniques for processing lactic acid/lactate salt mixtures are provided. Preferred mixtures for processing are obtained from fermentation broths, preferably from fermentation processes conducted at a pH of 4.8 or lower. The techniques generally concern the provision of separated lactic acid and lactate streams, from the mixtures. Preferred techniques of separation and processing of each of the streams are provided.
Claims20
A process for the production of lactic acid products from a mixture containing free lactic acid and dissolved lactate salt;
- said process comprising the steps of:
- (a) providing an aqueous mixture of free lactic acid and dissolved lactate salt produced by, and separated from, acid tolerant lactate-producing microorganisms at an average incubation pH of no greater than 4.2 and wherein the aqueous mixture has a final incubation pH between 3.0 to 4.2 and includes a concentration of at least 50 g/liter of a free lactic acid enantiomer selected from free L-lactic acid and free D-lactic acid when separated from the acid tolerant lactate-producing microorganisms;
- (b) preferentially separating free lactic acid from the aqueous mixture by selectively passing free lactic acid through a dense hydrophilic membrane into a second aqueous phase which includes a water miscible volatile amine weak base to provide a lactate salt of the volatile amine weak base, wherein the volatile amine weak base includes ammonia, trimethylamine, triethylamine or a mixture thereof;
- and
- (c) regenerating lactic acid from the lactate salt of the volatile amine weak base by selectively vaporizing the volatile amine weak base.
A process for the production of lactic acid products from a mixture containing free lactic acid and dissolved lactate salt;
- said process comprising the steps of:
- (a) providing an aqueous mixture of free lactic acid and dissolved lactate salt produced by, and separated from, acid tolerant lactate-producing microorganisms, wherein the mixture is produced by the acid tolerant lactate-producing microorganisms at an average incubation pH of no greater than 4.2;
- and, the mixture has a final incubation pH of no greater than 4.2 when separated from the acid tolerant lactate-producing microorganisms;
- (b) preferentially separating the free lactic acid and lactate salt in the mixture from one another to generate:
- a lactate salt containing stream;
- and, a lactic acid containing stream;
- wherein said step of preferentially separating includes selectively passing free lactic acid from the aqueous mixture through a dense hydrophilic membrane into a second aqueous phase which includes a water miscible volatile amine weak base to provide a lactate salt of the volatile amine weak base, wherein the volatile amine weak base includes ammonia, trimethylamine, triethylamine or a mixture thereof;
- and
- (c) regenerating lactic acid from the lactate salt of the volatile amine weak base by selectively vaporizing the volatile amine weak base.
A process for the production of lactic acid products from a mixture containing free lactic acid and dissolved lactate salt;
- said process comprising the steps of:
- (a) providing an aqueous mixture of free lactic acid and dissolved lactate salt produced from and separated from a culture of acid tolerant lactate-producing microorganisms;
- (i) the mixture being the result of production at an average incubation pH of no greater than 4.2;
- and, the mixture having a final incubation pH of no greater than 4.2 when separated from the culture;
- and,
- (ii) the mixture being separated from a culture acid tolerant lactate-producing microorganisms having a production rate sufficient to provide the mixture when produced from, and when separated from, the lactate-producing microoganisms at a concentration of at least 50 g/liter of a free lactic acid enantiomer selected from free L-lactic acid and free D-lactic acid;
- and
- (b) preferentially separating the lactic acid and lactate salt in the mixture from one another to generate;
- (i) a lactate salt stream;
- and,
- (ii) a lactic acid containing stream.
Dependencies are inferred from the claim text.